Why Don't We All Use Solar Water Heaters?
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- čas přidán 9. 06. 2024
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If you look at the rooftops of buildings in Israel, you’ll notice something. All of them have solar water heaters. In Greece and Cyprus you'll see the same thing.
But in the United States, less than 1% of homes use the sun to heat their water, even in sunny states like California, Texas, and Arizona. Why?
That's a question I've been wondering for a while. So this week, I decided to find the answer.
#climatechange #solarenergy #sustainability - Věda a technologie
I am Greek.
I have solar water heater, and I use for:
- 1 sink
- 2 wash basins
- 1 bathtub
- 1 shower cabin
- 1 washing machine (has dual water input hot-cold)
- 1 dishwasher (through a thermostatic valve)
Solar heater can be used to warm your home too. Is called heliothermy.
I have
- 2 sinks
- 1 bathtub
- 1 shower cabin
- washing machine
- wash basin
- dishwasher
----
i come home at the time or after sunset. All members of our house (4) use shower and bathtub at night before sleep and early in the morning before work/school. Approximately we use 4-600liters of hot water (depends on bath usage, amount of clothes, if there are guests, etc etc...). So we would need 600l water tank to fulfill our needs.
And just to mention, our input water from city during the winter is around 37F or 3C which mixes with hot water and cools it rapidly
Only works in southern Europe
@@digo8167 In southern Europe solar systems work excellently!
However last decade solar collectors has improved enormously. Can work even under cloudy weather!
Politics are more important than the weather. A photovoltaic system in Belgium (North) pay off the same time like Greece (South)!
@@digo8167 Nonsense. We live in central British Columbia, Canada, and we've had solar hot water for the last six years. it works down to about minus 25-30C. Below that, hoar frost buildup impairs its performance. It was a no-brainer and many of our friends are thinking about doing the same.
I live in northern europe in cloudy Ireland & it still works very well. We get free water for about 6-7 months of the year@@digo8167
Our tank is 300Litres but its often heated to a very high temperature > 70C so we get a lot more than 300 L of hot water out of it if it is mixed with water coming in at 10C. @beastlysun
I put solar hot water on my home in Florida almost 20 years ago and took advantage of the 30% tax credit. Took me 4 years to recover the capital outlay through reduced electricity bills - after that hot water has been free. In 20 years I have replaced the solar power pump just the once - it cost a mere $80. I, too, cannot understand why solar hot water is not mandated on all new construction here in the sunshine state. It would create a local thriving industry in making them and they would get cheaper as the economies of scale kick in.
The answer is simple: When you buy gas or electricity to heat the water the state gets the taxes on them, every year. With solar on your roof they would get less taxes....
@@thesolderman861The money does does evaporate, they are put somewhere else in the economy.
The fossil fuel industry does not want to lose profits. They release propaganda regularly among other tactics to malign all solar and renewable forms of energy so they can stay in business. This wont work forever but it will be a while until consumers choose renewables en masse because they are cheaper. Affordability is always the key factor.
More likely the energy companies and rich class political donations and sponsorship dries up, when strategic self sufficient solar and renewable systems are advocated for the public. Private monopoly needs the public dependent on thier energy for thier profits and public enslavement.
wonder what that does to insurance? they will find any reason to jack up insurance now
My wife's Grandfather built himself a solar hot water heater setup here in Victoria, Australia, in the early 1960s, and maintained it rather cheaply until recently. Never paid for electricity or gas to heat his hot water, for about 60 years.
At my home, we have a SolarHart Solar hot water service, thermosiphon type, electric boosted when required. It's a huge 300L system, saves us heaps on our electric bill. I would never go back to just a straight electric or gas hot water service ever again.
Solarhart solar hot water, thermosiphon
Got my Heat pump water heater installed in Maine for $800~ after instant rebates and now eyeing rooftop solar. Basically the same solar water heater my family had in Israel but with more steps .
Nice!
What do you mean more steps?
PV solar, more flexible but less efficient, I had a home with a solar water heater problem was when it needed to be replaced all the companies that used to install had all switched to PV only.
@@ian54589 yes, PV is _much_ less efficient at heating water - even gluing a water tank on the back of a PV panel will heat water better than the panel ever would using its electricity & a properly-designed water heater is obviously better still.
@@MatanMazursky a PV panel will collect at most a fifth of the energy that hits it & a heat pump will magnify the electricity 3x to 5x - more steps than letting the sun heat the water directly (& a lot more expensive).
We added solar hot water in 2019. We were strongly discouraged and told that photovoltaic was the way to go. But we've really enjoyed it. Not only is it satisfactory to have lower bills but also we're paying close attention to the weather, making decisions about when to use hot water depending on when we have it, rather than mindlessly just using it. If we're ever going to learn how to live lightly on the earth we may need to limit how we're consuming energy. We run the dishwasher as much as we want to, but not always as soon as it's full and that's fine. Long showers on sunny days, short ones when it's been cloudy three days in a row. That's real wealth, not spending the capital, but having enough sometimes and more than enough sometimes, if you pay attention.
I priced it up a few years ago. PV was easily the way to go. I could get a 6kW array plus an electric water heater for the cost of a solar water heater. That means I now have hot water for the same price, plus cheap electricity for other uses, plus a cheap water heater replacement when it fails.
I think the only time solar water makes financial sense is replacing an existing unit. That means install is much cheaper as the plumbing is already there. Very very few are buying solar heater new.
You make a really critically important point: people want the _ability_ to live in excess. They don't want to have to limit their consumption, regardless of how much it may benefit them. I think if people understood how little it takes to minimize consumption and how much they will benefit from that, it could make a big difference. A lot of people use "think of the environment!" as a motivator but that just doesn't work on most people, unfortunately.
Most dishwashers draw water from the hot water pipe, but heat it further anyway. Yes, hotter I put will help, but I’m not sure how much.
(We once had a dishwasher that had only a cold input and then heated the water internally. Took forever.)
@@shawnbrennan7526 Dishwashers actually _need_ the water to be extra hot because they don't use abrasion, so, they have to compensate by intensifying the heat.
@@Toastmaster_5000
Correct. My point is that most dishwaters will do that heating internally no matter what input temperature you have in the pipes.
Living in Pakistan, have a 20kilowatt solar system on my roof, then a solar water heater, problem is in winters when you really need it, it doesnot work here, but still i give its output to my instant electric water heater which has to work less now because 10 or 20% or 30% based on sun intensity that day is already taken care of by solar heater and rest will be handled by my electric heater.
So combining electric+sun gives me the high temp water I am used to. Luckily, the time i take shower which is around 9am here my solar PV array is generating enough electricity that my electric heater is also essentially running on solar so at the end I am using solar to heat water.
the total cost of solar heater here is around 400USD
and the solar system to make around 20kilowatt is 15thousand USD
Its a lot but it pays off in 10years.
You got a good price on that Solar PV system.
Dude this portrait of Clarence Kemp is almost assuredly Albert Einstein.
Thank goodness. I thought I was the only one.
That picture of Clarence Kemp is actually a photo of a young Albert Einstein
😂
I fitted one to my roof in the South of Vietnam 12 years ago the model I chose has a solar panel on the roof and the tanks in the roof space underneath, so it looks a lot neater than those you showed at the beginning of the video. The tank is also fitted with an emersion heater so on high consumption or a run of cloudy day we can heat water. We rarely do this as cold showers are most welcoming in 32 deg heat.
I was pleasantly surprised to find that the vacation house I stayed at in Barbados had a hot water tank on the roof. During the three months I was there, I didn’t see a difference in the temperature or the amount of hot water I consumed on a daily basis. It was a satisfying experience.
My mother in law has a solar heater on her roof here in Jamaica. She had to install a special drain to run water from the pressure release valve to the ground so that the extremely hot water water from the valve doesn’t burn anyone walking underneath…
Well in general you have backup electrical or gas heating, so no you wouldn't see a difference.
@@ianchandley sounds like a bad install lol
@@dailyrider2975 You'd have to turn on the backup as they're not automatic generally speaking. They're very efficient even on cloudy days.
Solar water heater we have is electrical, so it just turns on when it gets cold enough. Really old, so no programming to stop it from turning on either. We also have solar electric, so gets heated by sun one way or the other.@@jockspringer9457
The price of solar cells has declined rapidly in the last 15 years. They basically need no maintenance. The price of solar-thermal (water in tubes) has stayed constant and the system DOES need maintenance. If anything goes wrong you have leakage, thermal inconsistency and rapid system degradation. If you are thinking about solar-hot water then it is worth checking which one is really worthwhile for the whole life-cycle of the installation.
The lifespan of a solar water heater is 7-10 years.
That's in Israel where everyone uses one.
If you have a hot water cylinder heated with electricity the solar panels can give you 'free' hot water for much of the year. We're stuck with a gas combi boiler unfortunately.
Yes, heat pumps plus renewable energy is the solution most of the market will go to. But that solar water heater can feed the heat pump and reduce electricity demand and potentially the size of the heat pump. Whether it will make more financial sense to fill your roof with photovoltaic or also use part of it for a solar water heater, I don’t know.
And a solar water heater from the limited experience I had doesn’t need more maintenance than radiator-based heating systems that dominate the market in Europe.
Yes, with installation and maintenance costs in the US, even if you live in a hot area you'll probably never break even with solar-thermal hot water unless you live in an area with very high energy costs.
@@jmodified I cannot see a path to net zero carbon emissions that doesn’t involve making fossil fuels significantly more expensive. Yes, in principle you could use a purely carrot-based approach of subsidising renewable energy to such an extent that it becomes cheaper than fossil fuel-based technologies in every application.
Either way, solar thermal (or renewable electricity + heat pump) will be cheaper than using fossil fuel, be it via higher costs for the latter or subsidies for the former.
As someone that grew up in Australia where solar hot water is common, but now lives in the US, I've often wondered about this, particularly when there is discussion about installing photovoltaic panels and batteries to store the power for later use - it is much cheaper to store heat than to store electricity. If the end result you want is low-temperature heating, then capturing the sun's energy directly makes so much more sense than converting it electricity, storing it and then converting it back to heat later. The problem is that homeowners with PV panels are normally grid-connected and have net-metering so the expense of time-shifting (needing to heat water at night and in the early morning when PV panels are producing no power) is borne by someone else and usually by fossil fuel generators.
A heat pump takes the ambient heat and puts it into the water which is at least 200% efficient, sometimes as high as 400%+ efficient (COP 4). You can get far more heat per square meter of roof space by running a heat pump and a solar PV panel than using solar thermal, especially in cold climates. For resistive heating, you're correct but not with a heat pump.
@@imzjustplayin There is no world in which PV is more efficient than solar water heating, simply because of the huge discrepancy in initial energy capture. You'd have to fill that gap with magic.
SUggest learning basic physics. Heat pumps to be allowed to be installed MUST have a COP(COefficient of performance) over 3. Which means for 1 watt input you get 3 Watt output even in unfavorable conditions as proscribed by code. So yes, PV(20%) + Heat pump is MORE efficient than Solar Thermal(75%). You might do the simple math and say 60% >> 75% except the big problem that one uses about 5% of power in Hot water but 95% in electricity... and any Solar Thermal quickly tops itself off in a sunny location and collects no more power while PV keeps collecting. So, unless you can incorporate Solar Thermal into household heat, it is ultimately a waste of money + cost of making it not FREEZE. Exception is very cloudy places such as NE USA/Maine/Eastern Canada, Pacific Northwest if we are talking about North America @@Eagle3302PL
@@Eagle3302PL Thats just not true. PV is 15-20% efficient that translates to 60-80% thermal heat through from a heat pump. Compared to 65-80% from solar hot water.
Except solar hot water is always oversized to account for less ssunny days. So you might heat your water in 2h and waste the next 8h of energy. PV also heats water in 2h then lest you use the other 8h of electricity somewhere else.
@@Eagle3302PL You are wrong. HP takes the heat from around it and applies it to the local area. Meaning you recycle the same heat without having to heat more air up.
I'm from Turkey, and this is very common there. There are two significant issues with this system. One is that it deteriorates in just 10 years, and sometimes leaks from the roof can cause significant damage to your neighbors. The second issue is that if you live in a large apartment building, it places additional stress on the structure from above, which can lead to increased momentum in the event of an earthquake
My dear friend, solar heaters need maintenance. If you conduct maintenance annually or every two years, your solar heater will probably last twice than what you mention. By maintenance, I mean hiring qualified technicians to conduct it which includes cleaning the water tank and piping with running water and replacing missing parts (tubing, insulation etc.). Also, it is possible that your initial equipment misses some parts (like expansion tank) that will protect it from leaks or fractures from overpressure. If you ask someone to come and perform maintenance, ask them if your equipment needs to have any additional parts installed or replaced with suitable ones.
Greetings from your Greek neighbours
hello from Greece, of course we all have solar water heaters.
Hello!
Total cost is around 700-1000 euros
@@distilled-earth Γεια σου
Τι λέει 😎
The US is simple. There is an active effort by the utilities and those that profit from it to keep Americans from self sustainability. The more self sufficient we are the less money they make.
There's more to it than that. Many of the forces you speak off are fossil fuel companies who produce their oil, coal and gas in the US. The US is more or less self-sufficient in energy production thanks to fracking. Some would argue that going for solar would be going backwards in terms of self-sufficiency as other countries would contribute in its production.
Not that I'm against solar or heat pumps. I just think the self-sufficiency angle is weak.
I built a solar water heater for under $100 that heats 70% of our hot water. It is VERY easy to do. Basically just get a used water heater (FREE, it does not even have to work), strip the insulation off it and set it out in the sun. Then pipe the cold water supply into the free tank in the sun as a pre-heater to your regular water heater. It helps if you put the free tank in a insulated box with a window to form a greenhouse. That's basically it. There is no need to spend more than $100 on anything fancy. Let the sun do the work. :)
Make a video on it
Good history lesson. We are in southern NH. During the summer we use a batch solar heater in our greenhouse and in winter a heat exchanger in our cordwood stove. Both feed an electric water heater that makes up any short fall. I realize we are not typical but our DIY solution works well for us. The wood stove is fired up as I write this post.
My parents installed a solar water heater in the Chicago area and had constant problems with it so it never was as successful as it should have been.
Here in S. Florida, when I was a kid, most of the older houses from the 1920s and 30s had simple solar heaters comprised of flat metal boxes with a labyrinth of copper pipes and black paint inside with plate glass over the top surface. Nearby was usually a small electric booster tank in another insulated metal box to help on shady days. Sometimes kids (never us!...) would throw rocks and see who could hit the glass and break it. My grandmother's house, from circa the early 1930s, had this and I once helped change the electric tank heater by schlepping it up a ladder as a strapping, fit, teenager. Do you have any link to a modern-day self-contained solar unit?
They aren't generally self-contained, they're usually a rooftop panel & an indoor tank with pumps & control gear.
A rooftop panel feeding a shower or tap is very possible (a friend of mine has this in the garden) but it's generally not very useful & can suffer with calcification/limescale depending on your water supply.
Why done we just mandate everyone takes a cold shower? Save the planet. Imagine the amount of co2 neede to be produced to increase production of sola Waterheaters almost as bad as electric cars.well not as bad as we won’t have to enslave 100000s of kids to work in Lithium mines again but still pretty bad. Why do you support child slavery is beyond me
In Greece almost every home has one, and also we have a big industry building them (one of the last in the country) with multiple brands, driving the cost down
does it ever go below 0°C there?
@@csehszlovakze couple of days a year for most people :P
Solar is also electric. Days that you don't have good weather, you just turn it on for 10 minutes and you are ready.
We did have a solar water heater in Houston. It was really a 'pre-heater' that then goes to the 'regular' electric water heater. It went away when it started leaking about the time we replaced the roof, so it went away. Now near Nashville TN, we don't but do use a heat pump water heater.
Where I live we have 300 sunny days a year so we decided to install a 10,000 watt PV solar. Although it was expensive (about 25 k USD) it’s been a very good experience. The system is grid tied and has been trouble free and more than pays for itself. I would like to also install a solar water collector too.
There is also radiant heating I have seen in a few places. Where not only does the water go to the roof to warm up for hot water use, hot water is circulated around the house underneath special floor boards to heat up rooms. Surprisingly worked well in most mild winter area's. Even if water is freezing outside the special reflected light into the pipes often heated it up still.
In to 50's the beach house we used in Ocean City NJ had simple 55 gallon drums over the outside showers.
1st person back from the beach had to be careful not to get scalded
Last person got a cold shower
I have a solar water heater on the roof of my house. There is one more thing I have to add is to provide insulation around the tank. I noticed when the sun sets the hot water does not last long as it loses heat when the sun sets. I also have an electric heating coil in the tank which I use at the moment for the time being.
I was in Turkey on holiday recently and on the drive to the airport I noticed that most of the rural houses had one of these on the roof. What's weird is that few houses had actual solar that you'd think would be fabulously useful for running stuff like AC in the blazing heat.
Most certainly because of the initial cost. The cost of solar water heaters are within reach while pv panel system could be 30x or 40x more.
I spent all the previous winter in Turkey, and it happens that the solar water heater was leaking at that time, so i could've watched as it was repaired.
These heaters are incredibely low-tech, 2 barrels, 1-2 boxes covered with class and a (probably) copper wire inside, and a pvc pipe connecting them. They cost about 250-300$ at any market in Turkey, and if you don't know how to connect tehm they'll do it for 50-100$.
Solar panel that would generate any sufficient amount of electricity would cost way more, so it won't make any sense to install. And btw, most houses in rural areas don't have an AC, they can't afford it. Even in a "rich" touris city they have AC mostly in a rent places for tourists.
Thank you for discussing this. It is one of the keys to getting off of fossil fuels. Solar water heating has a lot of potential beyond just hot showers.
Fossil fuels are good, stop being a weaksauce liberal LGBT.
My response wouldn't post so I'll just use a southern Bless your heart.
Yeah…lmao
In the UK my Solar water heater is 10 number 1.4kW solar thermal panels.
The hot water is pumped to the house and heats a 300 litre insulated tank.
This gives 3 days worth of hot water.
The temperature of the stored water can be set to boiling point if you wish but we keep it at about 60c.
We use excess hot water to heat the central heating system via a heat exchanger and in summer a separate heat exchanger is utilised to heat the swimming pool, remember it is delivering 14kW when in full sun.
In warm weather we have had the swimming pool at 32c but the hot water can't really be turned off as the glycol/water mix in the panel will boil at about 135c and cause problems.
The system is pressurised to 3.5bar to raise the boiling point of the panel fluid.
It provides hot water for about 10 months of the year, partial heating in spring and Autumn and pool heat in summer.
I've been told that solar thermal hot water requires a lot of maintenance. What's your experience ?
@@grahamstevenson1740 been installed for 11 years with zero maintenance. Never had to repressurise and have never changed the glycol. I washed the panels off once. Still working well , made over 100 kWh in a single day.
@@andrewstafford-jones4291 So there's no shortage of cowboys dealing out dodgy advice ? Thanks.
@@grahamstevenson1740 Not sure as I don't have a reason to talk to them.
I know they recommend changing the glycol/water mix every year but that's just uneconomic.
It would cost a lot to change my glycol, I think it used 8x25litre to fill it.
@@andrewstafford-jones4291 Good to know, 100 kWh in a single day though?
With three teenagers in the house in AZ, the solar water heater had NO problems keeping up with their bathing and ours.
Even in a cold climate, as long as there is sun, you can at least use a solar collector to preheat water and reduce the energy used for the final heating.
Whoa, I never knew. Are solar water heaters so expensive in the US just because of the economies of scale, or are there other reasons other countries can get them to such a cheap price?
I'm not entirely sure what drives the huge price gap. I think
“I think”
That’s nice. I try to too
That's the piece I'm confused about too
@@elfrjz what the problem with electric stoves
@@elfrjz i guess gas is cheap there cause here lng is very expensive while electricity is relatively way cheaper
almost not worth it unless you are a plumber and do it yourself , most people don't change the anode and the tank rusts out
I live in the Philippines. It's hot. We don't have water heating aside from boiling a kettle. We wash and clean with the lukewarm water that comes out of the tap at the 30C ambient temperature.
I am in South Australia near the southern 35th parallel. We have a 22 tube Evacuated solat system, it provides all our hot water for 40-45 weeks of the year. Then the elecric booster is turned on for a system boost. As soon as possible we turn the booster off again 😊 we also have a large reserve tank
Great video! Just one thing I think you left out... Solar water heaters are great for your house, but they're not good for large buildings. In capitals and large cities, most of the population live in apartments. In countries where there's less concentration of population, there are more houses and fewer apartmentsnd that leads to great statistics when it comes to percentages. In Argentina, where we have low concentration and many people live in houses, solar water heaters are are becoming increasingly popular.
I have one installed in a country house where, since there are no buildings to provide shade around (just trees, but there's good exposition), sometimes it boils the water.
Nearly all the pics of Israel were of high density buildings. It's not impossible. It's just not beneficial for land owners to absorb costs. They simple don't care about anything besides money in their pockets. You could argue that's how investments work, but housing is a captive market and is heavily prone to exploitation. If we are forced to pay high rents then they should be forced to supply the market with high quality goods.
Solar thermal is one of those technologies where long-term thinking permits sky-high upsides but we are a species that thinks in the immediate short-term.
Solar thermal is one of those rare "Eventually, no matter how relatively less ideal the circumstances are, it *WILL* pay off" technologies where the only real limitations is getting the ball rolling so that economy of scale can kick in.
Personally I think this is where governments come in but either way we need large scale production of these systems in North America.
or import from places that already have the economies of scale
I looked at a glycol system (Canada). $7k+ before installation, probably 10 or more after. I would never spend that much on hot water, certainly not within its lifetime.
@@alanj9978 I don't think you're *wrong* by any means but I think you might be surprised.
I know hot water accounts, on average, for about 15%-20% of home energy use.
That's admittedly about $30-$40 a month according to BC Hydro's average used estimates (greetings fellow Canuck!).
If one is able to make practical use of the heat obtained via a central heat exchanger getting an average up to $60-$80 a month.
Guess it really depends. If it's able to supplement in-home heating than its a 7-10 year pay back. Otherwise it would be closer to 15-20 year pay back but should out last that by a significant margin.
@@Cheebzsta It's more like 30 years at $40 per month vs. 10 years at $80 per month, assuming you would otherwise use that $7,000 for very cautious investments (5.5% or so). But how much more than $7000 would integrating the system with a central heat exchanger cost? If it's an extra $4,000 that puts you back out to 20 years, if it doubles to $14,000, you're back to 30 years.
Interestingly, a pure water solar collector is exactly as efficient as a PV one, ie both get the same energy per square meter of collector. But if you use the PV's electricity to run a hybrid hot water heater (with heat pump), you get 3x the hot water. Thus, if you have a PV system, just add a few panels to power the HW heater and you are far ahead of having a water solar panel system (with its valves, freeze protection and pumps). I did that with my solar home, and my Rheem heat pump HW heater works flawlessly.
Plus you don't have route water to the roof and can use the electricity for other things. Much better solution.
@@drewp4
Both of you are right. Just one comment.
Thermal solar panel efficiency is 90%.
Photovoltaics solar panels efficiency is less than 20%.
@@ajarivas72 True, as it is, but the actual panel area of a set of evacuated water tubes isn't as dense as a flat silicone sheet, so the amount of BTUs per sq meter of roof area is almost identical. And if you use PV, -no pumps, valves, drain down tanks and such. The net result is PV to a heat pump water heater is about twice as efficient as water solar panels. But hey, either is better than a fossil fuel WH!
@@nicklappos
The panel area density of an evacuated tube solar water heater is identical to a PV panel, just add a mirror 🪞 below the tubes on the roof and the heat is reflected to the tubes from the bottom.
My evacuated tubes solar water heater mirror 🪞 enhanced recibes 5 times as much Sun ☀️ as a normal evacuated tubes solar water heater.
I reflect Sun from the bottom, sides, front, behind and top. It gets suns from all directions from sunrise to sunset. Cloudy days no problem.
@@nicklappos
I have several wind generators, so I can energize the electric (resistance) boilers when there is plenty of wind 💨.
I use the electric boilers as dump loads for the solar and wind systems. Side effects: very hot water galore.
I built my house 13 years ago with consideration of solar water heater, i.e. dimensioning the water tank and having extra coil for solar heated water input. But the money it took it back then seemed to be too high to justify the purchase, so I thought maybe later. I checked few times in the years between then and now and never it made really sense - the green subsidiaries rose, but the installation companies ate it all and did not pass it to customers. As a result, when I checked it last time, I calculated ROI to 19 years. From the sources I have, this system does wear down and the common life span is between 10 and 15 years - so it didn't make any sense. The ultimate end to this idea was when I purchased a PV solar system and a heat pump. The PV panels generate excess enerrgy like 3/4 of a year and this is turned into heat in the tank with 400 - 550% efficiency. So I think it beats the solar water heating systems and serves dual purpose. Both PV solar system and heat pump (switched to it from gas) make sense on it's own, but combined the ROI drops down significantly.
Some factors to take into consideration:
a) The maintenance cost and lifetime of the heat pump. Heat pumps are mechanical devices and depending on usage domestic heat pumps can require replacement within 8-10 years. They need servicing at least annually, even if only cleaning of the external radiator.
b) A resistive heating element may give a much shorter return on investment than a heat pump depending on the situation. You'd need to "crunch the numbers" to be sure.
c) Solar panels work really well when the sun is out, but produce virtually no power when there's excessive cloud. In some countries/localities there will be a fair proportion of "miserable" days with either very little or no power generated from solar panels. That's no doubt less of an issue for areas like parts of Australia and other similar climes.
d) An on demand" gas water heater is very efficient as it only heats water when it senses water flow in the hot water lines. Accordingly it has a low running cost, even if gas prices are a bit higher. The capital and installation costs aren't high and additionally that system does not require a hot-water storage tank as it heats water flowing through, and only when there is actual demand..
e) As I understand it, in many countries, solar water heaters and installation used to be very expensive but prices dropped within 10 years and the systems became more sophisticated and efficient. In some climates frost protection is required, but modern systems take care of that by using a heat exchanger between the hot water system and the panel fluid (which contains a frost-free liquid).
I all depends on the exact situation.
@@ericapperley7411 a) I will see in some years after warranty. I have friends with heat pumps running for 10-15 years and no issues. Furthermore, the pump component itself, which used to wear down with older (like 2 decades plus) heat pumps is only a small fraction of the cost and can be replaced. Modern ones don't wear much, theyr're digitally controlled with smooth start and run out. Parts are available and I doubt Samsung will go out of business either. Servicing is not "at least once a year" - for al-in-one units it's not usually required to service it during the life time of the product, unless remote diagnostics show a problem. For a split system (like I have), servicing once a year during the 5 or 6 (forgot) year warranty and I have a fixed price, I thing it's something over €30. Some companies charge double, it's up to you as a customer to accept or change to another authorized maintainer.
The heat pump costed me less than €8000 complete with installation, 11 KW, both heating and hot water, WiFi, everything included. ROI would be 1.3 years (!) due to peak in the gas prices, if I got a subsidiary for changing from gas (which I did not qualify for due to my age of gas heater, although it's ironically at it's expected life span), so now it will be little over 4 years (estimated - my calculation, not a marketing trick of a seller, but it includes substraction for a cost of a new gas boiler, which I'd have to put down if continued with gas, roughly €2200). Mind also, that having solar system helps the heat pump ROI too.
b) AFAIK, resistive heating is usually among the most expensive heating options, unless you are passive or very close to passive (or in favourable climate). Especially it's not a good option for houses with large heat acumulation capacity (which I have and I am very glad I do).
c) Not true that solar panels don't produce electricity with cloudy weather; they can produce much less though, that's true. Typically the output does not fall under 1/3 from spring to autumn, and in extreme winter conditions it can fall to about 15%. But the solar field is the least expensive part of the system and is typically dimensioned to cancel some of the difference, so in my case it's around 50% of required output during December, which is the worst part of the year here.
d) On-demand gas heater is a product that can be very feasible in certain scenarios, but it is not (AFAIK) by a wide margin for a typical house with typical family usage profile.
e) I don't think the systems are particularly expensive here. I think the part I'd have to pay would be around €2200 (complete, including installation) and the investment would be the double (half would be paind back to my account by environmental programm). Still, with the system being that cheap, the ROI came up to 19 years - beyond the life expentancy of the system! Simply because it does so little as for the effect on the overall house bills. I considered it seriously 3 times over period of 10 years and found marketing of those products is far away from the reality.
That is my take on your points. But I'm not an expert, just interested in the topics.
The solar thermal array on my house in southern England is plumbed into the central heating system in such a way that it diverts to the underfloor heating also. The PV array is used to run the ASHP for a fourfold gain in heating applied to the house.
Cost of all that?
@@LoremIpsum1970 The whole six bedroom house and large garage was built for £235,000 . We did most of the installation work ourselves, and got good prices for what we bought in. The Solar Thermal array was less than £1000 in all, the PV was £10000, but it attracts a decent FIT which has paid for it. The ASHP units were less than £1000 each and are fitted in the loft, No outside noise, and full protection from the weather , whilst being part of the Ventilation system .
Love that at 7:27 you see Australia twice on the charts showing water heater capacity with two different results.. is it that hard to add the source of your data at the bottom of any graph or quoted statistic?
I would like to add that my system had a glycol based liquid that circulated to a heat exchanger on top of a 75 gallon storage tank that fed a traditional natural gas water heater. It needed periodic maintenance and replenishment of the glycol (anti freeze) liquid. Service cost about $125 a year. So, a complicated system with many failure points and maintenance costs. This was 40 years ago and as I mentioned it only worked for 15 years before pumps going out. It was also time to replace the tank.
I would like to thank you clearly describing the different administrations approach to energy politics and how it has affected the nation. I found this out in collage years ago and it made things very clear for me. I hope that this has the same eye-opening effect on other people.
Thanks for watching and the kind words!
Yes! We are all hoping for another idiot, I'm sorry, I meant to say Carter, so we can save a few bucks on "clean" energy solutions.
If it weren't for the Government, most people would be happy and " clean" energy would have taken over a long time ago.
The ignorance of some knows no bounds!
No administration is against solar it’s just some like taking money from other people to pay for it and one believes you should use your own money to buy yourself one.
Two other factors .
1-code restrictions and those evil HOA rules .
2- Americans place cost above everything else .
Quality , support of workers come second .
HOA's legally cannot stop you putting solar on your roof.
maybe ,but would you want to go to battle with some crazy Karen everyday . People that run HOAs are usually control freak nut cases .😂
@@JohnPilling25 Correct - however they can dictate that it is not allowed to be visible from certain vantages. The red tape and dealing with Karen and her best friend Rita on the HOA committee is also enough deterrent.
My family got a solar water heater on our roof in California in the early 80s. Added a lot of extra hot water for the house. We could all take showers without having to wait inbetween for the water to heat back up. In the 90s, there was a freeze and the panels started leaking. But by then, the company had long gone out of business. To this day, those broken unused panels still sit on my parents roof.
Yeah I see them dead everywhere
5000 to 15000 dollars!? I have collectors for 7700 kWh on my roof (cloudy, cold Netherlands) for 8100! And that does a LOT more than "just great water"! Why the F is it so expensive in the USA?
Crazy right??
They cost 800.- as a set in Europe (imported from China), I'm sure this is also available in the US. Just don't ask the companies who also install them, since they can add whatever they want.
This channel should have millions of subscribers
Soon hopefully!
Do your part: share it with everyone!
Excellent video - I didn’t know how few solar water heaters Americans have and how expensive they are to buy there. Here in Thailand I purchased a solar thermal water heater for $1,000 and the savings has already covered the initial purchase price. In the UK the MyEnergi eddi is a popular power diverter that takes excess solar power that would have exported to the grid and uses it heat hot water.
I was under the imperial system until about the early 70s which is when we started changing over to metric. Conversion between the two system is a pain in the arse but not a problem. The problem arises when the US system rears its ugly head. Mostly because I don't know it. Make whole hearted change and it is a simple as falling off a log. Only problem is visualising the new units, not one problem with measurements,
Here in Mexico theres a push so more homes start using solar water heaters. Specially if you buy a new home. No tax credits from the goverment though. The thing is that in certain states, the water you get is hard water and that clogs and damages most of the heaters. Solar or not. So you have to replaces or do maintenance often. Also the cost of a solar water heater represents a big investment that will take several years to pay off.
There's a gap in the technologies described here: Southern countries have these thermosyphon water heaters on the roof, they are efficient and need no electrical pumps. They provide water disinfection and water outage remediation. But they are heavy - and are only on houses made of brick. In Austria you wont find these, because it gets way too cold, you need a pump, heat-exchanger, and a glycol based transfer medium to a storage tank. Thats way more expensive, the large tanks are usually in the basement, because the houses are made of wood, and they require electricity to work.
There are almost no fully integrated heat pump solutions to date where the heat pump that cools your house heats your shower water, or where the heating of your house cools the fridge.
sooo friggin interesting!!!
Glad you thought so!
@@distilled-earth would love to see more maps like in johnny harris videos.. like id love to see a map based on percentage of population using solar water heaters 😁😁
Great video! Next step is PVT panels (photovoltaic+thermal). Basically electricity+solar heater in one. Most use different liquid than water that is more thermally conductive, but same idea.
PVT is much less effective than a dedicated water heater but hey, if you've got the acreage of PV you may as well capture some of the 4 fifths of the sunshine that isn't making electricity.
I don't totally understand why, but PV + thermal has been tried over and over around the world for decades but it just never takes off. I don't know if it's people just panicking about water near high voltage or that there's rarely exact matching between the need for heat and the need for electricity, but it never takes off...
@@cbarnes2160 Because of poor efficiency. You are better off having a solar water heater and pv panels separately.
I think the real next step is PV+teg. TEGs can generate electricity even at night.
@@cbarnes2160PV is basically maintenance free so adding a liquid loop greatly increases complexity and adds maintenance. The extra cost is usually better invested in just buying additional pv panels and get more electricity.
My parents house in Molokai, HI have had a solar water heater on their roof since the 80's. In San Diego I have a solar water heater for my pool but I think your video just got me thinking about putting in a solar water heater because the price of gas skyrocketed this year.
In my 5 bedroom house in Spain 6 years ago I was approached by a local company who suggested I should have a solar water heater. They told me that there where government grants available and it would only cost me €3000. Being a practical person I decided to look into it in more detail and found that I could buy a complete 300 ltr system from Baxi for €1200. .I also had to spend €130 on extra plumbing pipes and fitted the whole system it two days. So for the last 5 years to provide hot water,I have only used the electric water heater for less than 30 days each year. It’s a no brainer.
An electric water heater can be converted into a solar heater by adding a PV panel and changing the heating element to a 12 volt element, or solar collector panel to heat the water directly and use the electric tank for storage.
Passive solar water heaters (where the tank has to be above the panels) are really ugly and don't fit in with most sloped roof residential homes. In Israel, where most people live in apartments with flat roofs, this is less of an issue. Also, in Israel, the water is very hard (lots of calcium deposits from heating water), making the maintenance of these things a nightmare. Most people keep them on their roofs for getting a building permit, but heat with electricity since the panels don't last very long due to calcium clogs in the heating pipes.
They instal those even on sloped roof (suport brackest are modyifyed),i dont think they are ugly
@@Adam-bw4lw Yeah. most the world uses these water heaters.. they are fine
I even managed to feed my chloteswasher and dishwasher from it by using a termostatic mixing valve
100%…too ugly and 3rd Worldly.
Who GAF what they do in pooholes?
When we moved in to our new home in Tenerife 24 years ago, there was an electrical boiler. We bought a Solar Water Heater and the electrical bill dropped 27%. Now also our jacuzzi is 100% solarheated.
My company make solar photovoltaic water heating systems from as low as 1299$ but we only sell in Romania for now and we could send to All EU country's. I own the cheapest system for 4 years now and it works perfect with no maintenance. It covers all hot water for 80% of the year, even some winter days that are sunny. The sun is the best!
2:44 Wow Clarence Kemp looked a lot like Alert Einstein ! Hold on...
Incredible video, very well researched!
Thank you!!
I've had 9 4x8 Heliodyne brand thermal panels for about 30 years now, I made a quanity purchase of 40 of them, so got them cheaper plus a breakon the shipping. I sold and installed all of them except my 9, 6 on my shop, 3 on my home, both have radiant floor heat. Augmented when needed by a homemade wood boiler. A friend did a recent YT video on my setup, which I take for granted after all this time, and I was somewhat stunned to see many reactions like "That can't work, it must not get cold where you are, they'll never pay for themselves" and similar. They are wrong!
Solar heater are great in Countries where temps do not drop bellow freezing, otherwise pipes burst when freeze.
I can relate to that... from northern Alberta, Canada, where for half of the year the temperature can *remain* below freezing 24-7.
Would you consider publishing your sources in the description of videos? It would be really useful for research purposes to read sources and get more in depth information.
Great content as always!
yup! i usually do, just didn't have the time on this one
@@distilled-earth understandable, thanks for the great work as always.
Too busy grooming his beard@@distilled-earth
This looks like a great opportunity to import the European's tech
And their policies too!
It was an Israeli invention first!
As a user of solar hot water (in NZ) I have this to offer; once on solar your use of hot water increases considerably! Long hot showers, hot laundry washes, etc etc. Well, why wouldn't you!!! And while I am on the subject, the reason to have vacuum tubes as opposed to flat plate collectors is that they are like Thermos Flasks; they have the advantage of retaining the heat in the water as the sun heats it. Once hot enough it is then pumped down to the cylinder. Flat plate collectors lose the heat quite quickly on a cold day, particularly as the water is getting up in temperature. It is nothing to do with them being round.
The vacuum tube variants also don't get clogged with minerals, which can be a an issue in many places.
Washing machines use cold water then heat it
In Australia solar water heaters were popular in the 70s-80s, however corrosion, backup heating with electricity, and the major cost of purchase made them less desirable. Most houses now use solar panels and heat water with instant gas, or gas heated tanks.
When I did change my water heating system on my house, I opted for instant gas. Far less maintenance, cost and not having a heavy tank on the roof made choice easy.
heating water with gas when you have solar panels on the roof is a little backwards however. Heat pumps in combination with regenerative energy source means complete idependence of fossile fuels and long term will be cheaper.
@@maxmeier532 well not really, heating water instantly takes about 22kW, a storage system requires 3 times the energy. So instant gas for here is the most efficient and cost effective way. I use heat pumps for heating or cooling the house.
Ive got one here i australia and wouldnt be without it and on days when theres no sun i just flick a switch and heat water for 30 minutes and then theres plenty of hot water for all of us👍😊
Solar heaters are widely used here in your immediate neighborhood ( Mexico) . Its fairly recent, about 10 years, but most new home constructions have them and people are making the switch from butane a lot. Transición energética amigo.
What city?
In Monterrey very few people use solar water heaters, fewer than 1% as in the USA.
@@ajarivas72 Aqui es SMA, mucho tambien en Qro hasta la CDMX. Its a pity you don't usem over there, we really do have the right climate.
@@elpix
Al mío le puse espejos 🪞 por todos lados. Recibe calor solar desde el amanecer hasta el atardecer.
El techo está literalmente tapizado de espejos 🪞 y de todos lados rebota la luz e incide en el boiler solar.
Todos los días sube la temperatura del agua a 99 °C.
This was a great one!
Thanks!
A solar water heater in Israel costs $600-1,400 (not including installation)
When I was a kid, hot water for showers at our vacation spot in Maine was provided by a coil of black pipes on the roof of the bathroom facility. That was it! No tanks. The volume of water in those pipes were such that you still had hot water in the morning. Never forgot about it.
I had a solar water heater in CA, back in the 80's. When it failed, the cost of replacing it made it economically foolish to do so, and that brings the discussion to three very important facts to understand. 1) The "government" is not the answer to anything, ever. 2) People, as a whole, cannot be counted on to do the right thing, unless it is in their best interests, from a fiscal standpoint. 3) If you want to see fundamental changes in how people behave, make it much easier or much less expensive to do something differently. I recently replaced a conventional electric hot water heater with one that includes a heat pump; my energy usage for heating water is down 75%. If and when I have a solar array large enough to supply that energy, I will essentially be heating water with the sun.
For those not paying attention: This video gets it all wrong! It is VERY cost-effective to use a combination of solar and a heat pump to create hot water, and it's much better for the environment if that sort of thing appeals to you. If you just want to save a bunch of money, it's worth the small investment.
True solar hot water heaters are a non-sequitur; it is far more effective, from both a financial and efficiency standpoint, to add solar panels and a water heater with a heat pump on top.
Maybe the integrated panel with the hot water tank, both on the roof, is good for cheap solutions in hot or warm climates without freezing temperatures.
And some panels for 12V PV.
But when you can spend more money, it's better to go with your solution. And I also don't live in a hot climate, so no cheap roof solar water for me. I tend to a PV only solution on the roof and do the rest in-house, without water pipes running to the roof and back...
@@richard--s - I have no water pipes on the roof, just a heat pump on top of a conventional electric hot water heater. If and when I add a PV array, the electricity from that will be what drives the heat pump, for the most part.
@@jasonbroom7147 yes, that's a flexible way to use the sun. With good efficiency over the heat pump.
Heat pump water heater + Solar PV makes far more sense both from a simplicity standpoint, and an economic standpoint. Solar PV is always delivering useful electricity while a solar water heater contraption isn't always delivering a useful amount of heat (especially in cold climates). So if there is excessive capacity due to the warm ambient temperature, the solar PV can be used for other purposes. Warm water isn't hot water so in the winter time, Solar Thermal isn't sufficient while Solar PV + the heat pump guarantees a certain amount of heat will be delivered by the heat pump due to the thermostat choosing the cutoff point.
Solar thermal had its time but its time has passed and Solar PV is the way to go from now on.
@@imzjustplayin - Some very good points, but I will mention that in many parts of our viewing area, solar and heat pumps simply can't keep up during periods of actual winter. I have solar panels and a heat pump hot water heater, but it has conventional electric heating elements for a reason.
😂 a lot of America's problems with energy wouldn't exist if it weren't for the Democrats. Renewable energy is great but let's face it. It's not practical for every situation and kissing Carter's ass is laughable to say the least.
Why do CZcamsrs commonly use maps that color land blue? Aren’t most oceans bluish? What land is best represented as blue? It’s confusing when quickly looking at a map.
NY you need a separated glycol system with a heat transfer unit. Add bldg codes, town permits (only approved units) and inspections headaches.
From my viewpoint they are an outright fraud. I had a new house built four years ago to meet the latest energy efficiency standards. To meet the standards, I had a supposedly super-efficient evacuated tube solar hot water system installed. My electricity bills have never been higher and my power company estimates the hot water component of my electricity consumption at around 35-40% winter and 60% summer. In an all-electric house with two people who shower no more than once a day, use cold water for laundry and have a dishwasher that heats its own water. And yes, I have had the manufacturer's "expert" representative inspect it and tell me it's installed correctly. I won't be wasting my time and money installing anything "solar", including PV any time soon.
This is a very weird story. Just because you got tricked somehow does make the tech fraud. Millions are using those. I installed two myself and know they work.
In fact, carbon dioxide, which is blamed for climate warming, has only a volume share of 0.04 percent in the atmosphere. And of these 0.04 percent CO2, 95 percent come from natural sources, such as volcanoes or decomposition processes in nature. The human CO2 content in the air is thus only 0.0016 percent.
I had one in my last home. The water was super hot. The impeller on the pump disintigrated. Replacement parts were no longer available. All the people installing the initial 2-3 years moved on to other persuits. The tank was so efficent that I could turn the system off and go on vacation for two weeks and still remain hot. The system had a radio controlled cutoff used by the local electrical company to shut off the electric backup during peek power usage. I will never again use a system that someone else can shutoff on command.
Why is Australia on the graph twice? I'm assuming that one of them is a different country? - Pretty much all new homes in Australia these days have either a solar hot water system or a heat pump, but we still have a reasonable amount of other methods used on older homes.
That was a typo (face palm)!
I built a solar water heating system in Michigan around 1979. The useful days per year were about 50%. Even so it paid for my materials coat in 2 years. In the summer I had to cover one of the two panels to prevent overheating. We used close to zero electricity to heat water for 5 months of the year.
In Greece there are some solar heaters that help on heating or airconditioning (with a heater pump). These systems are pretty much expensive but it saves a lot of energy and money.
My home town is in northeast China. It can reach -25C in winter easily. Solar water heater is still a thing, on top of tall condo buildings. You don’t need to fill the tank with water if you fear the water line can freeze during winter night. You only need to spend a little electricity to pump coolant through the system, then exchange heat from coolant to water.
It’s so frustrating to see solar water heater is almost none existence in souther California. There are 300+ sunny days a year. We need to consume energy to heat up water and cool house. If there are more sold water heaters on just residential roofs, you get almost free hot water, and spend less money on air conditioning.
Works great when the temperature is already 32C, but not 32F. I had a solar pool heater on my roof in Florida. Ran it in the fall and spring to get a couple of extra swim days. Never worth the investment. You see a lot of them removed and sent to the landfill when it comes time for a reroof. Natural gas pool heater is the way to go. If you don't have natural gas, a heat pump heater will let you swim all winter, although it won't be hot enough for a spa in the winter. Only natural gas or propane can do that, but propane is way too expensive in Florida.
I remember when our 3rd worse president, Carter had solar water heater panels installed on the presidential residence. At the time, every new government building included them. Our local library made a prominent display of their panels, exchangers, and water storage tanks. It was impressive to look at but did very little. After all, how much hot water do you use at the library? Not like people are showering and washing clothes. Anyway, the Carter's installation of 32 water solar hot water panels done by lowest bidder (or Billy Carter maybe) damaged the resident roof. The leaks were causing water damage to national treasures so when the panels were removed for roof repair, they were never put back up. All the water heating panels from that time 50 years ago are long gone. Sure, many people have solar panels today that generate electricity (actually, I do), but that's not the same thing. Still, even photo-voltaic (PV) solar panels are only financially viable in certain places based on government manipulation of energy prices. As I always say, "All energy is local."
Man Carter sucked..
German here, we have a combined heat pump solar heater system. The collectors on the roof look exactly the same like the solar electric panels, except for the blue glow. Water is just plain black. So we got two panels for water on the roof, and the hot water tank is situated in the basement. This way it keeps the heat longer (or better more efficient) especially in the cold seasons. Because it's then warmer in the basement than on the roof. The heat pump takes over for the water if the heat from the roof is not sufficient. And it also heats up the entire house. The rest of the roof is covered with solar electricity 7,5kWp. We always have a sensational low bill for heating of 480 Euros per year. When you should know that Germany has the highest energy prices in the world. My inlaws told us when we built the house to use oil for heating like everyone, but today if they see our energy bill they tend to cry :) :)
@Distilled In your bar chart, how come there are two Australia's ?
Is there another Australia out there we don't know about?
or have you just labeled New Zealand as Australia as well, which is understandable :)
(Time stamp 0:34 sec)
I tried putting solar heaters on my roof, but only available ones in my country are the ones with closed loop systems which require a gigant water heater tank and special fluids, so it's pretty expensive compared to my countrys living standards. I put solar system on my roof and this watter heater system would run me almost half the cost of my entire solar, so I just decided to put a small electric boiler and still have a gas boiler as a backup for winter.
I have 2 200wh panels in an indoor window. My question is will the panels still generate heat when not plunged in? with summer coming I wonder if I will need to take them out.
Very big obstacle to solar hot water in the US are local building codes and home owner associations.
"I don't want to see that ugly thing on my neighbor's roof every time I look out my kitchen window" and similar attitudes. In some areas you run into the same thing with solar panels, too.
Great videos. Enjoying them
My parents installed a solar hot water system when I was a kid, and when it wore out (after 20 years or so) they liked it so much decided to get a new one that was basically exactly the same. They have plenty of space on the roof, and we're far enough north here in Australia that it makes sense, they have to use the electric booster but not too much. For me though I decided to replace my too-small and quite old conventional electric system with a heat pump. It was definitely more expensive (even after rebates) but it's been fantastic. I chose to put more photovoltaic solar on the roof because I have much more limited space, and the heat pump is timed to only heat in the middle of the day. So far it's used solar energy definitely more than 98% of the time, so my heat pump running from solar electricity has been more solar than my parent's thermal solar hot water system! This is even more the case further from the equator, because you have to use the electric booster on a solar thermal hot water system for more of the year.
subbed, keep making great renewable tech videos!
I'm a plumber so fitted my own in UK. No labour costs involved so have got my money back already.
The main problem is too complicated system + expensive labour charges.
It should be really simple
it doesn't even use pumps
Why does the solar water heater cost 5k in the US? In Greece a 47 gal solar water heater cost less than 1k.
I live in Macedonia and I have a solar heater combined with my central heating and electical. The actual heater is below the roof. I use the electrical heaters only when the central is not on or when it's not too sunny outside. So mostly in some days of April and October. In the other parts of the year I turn it on rearly.
If you take a shower before the sun comes up how cold is your shower during the winter? Do people just switch to showers in the afternoon or at night? If you answer please respond with what latitude you live at.
Peru is actually a very sunny country. I lived there for 3 years. Everywhere had solar powered hot water heaters. Long story short, I didn't have better than a lukewarm shower even once in that 3 years.
Because in some countries it's too cold in winter for an outside water tank. They have a modified version.
A modern gas heater is a lot more than a Zippo under a tank of cold water. A condensing boiler condenses the water vapour generated by the combustion of gas and uses the heat of condensation to pre- heat cold water going into the boiler. The process is assisted by fans to guide the flow of combustion gases over a heat exchanger.
7:29 Australia has so much solar heating capacity it appears on the graph THREE times!!!
I live in Texas. Electricity is CHEAP. In ISRAEL electricity is EXPENSIVE. I'm surprised you didn't use Hawaii for comparison. Electricity is expensive there too. If it was convenient, and minimal maintenance, I would use a solar water heater. However, the Return On Investment is awfully long.
And Federal Government Tax Credits only pay IF YOU CAN ITEMIZE YOUR TAXES...
Just my $.02
Here in Northern Europe some use solar water heater. But the downside is in the winter time when there is no sun but clouds and rain for days or weeks. An external tank will burst in winter when frosty temperatures...
Our solar water heater is the best purchase of my life. We never need to heat water via electricity or gas. It has 16 tubes with a 220 litre tank and it cost us $360 USD inc. install in 2016. We live in Mexico.
One other huge factor in the failure of solar water heating to be more successful in the U.S. market place was the industry itself. A solar "water" "heater" is both a plumbing and a heating product yet the retail plumbing and heating industries, where the expertise was, did not embrace and promote this technology. As a result of this and government incentives that caused the market to explode, a new service industry, completely separate from both the heating and plumbing industries arose. Unfortunately this industry was populated by a lot of people that were more interested in hype than substance, short on technical expertise and service after the sale was low priority. Solar water heating got a very bad reputation that is still haunting it.