Best Insulation Methods for Crawl Spaces Based on Research Study
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- čas přidán 26. 12. 2022
- In this video, Michael goes over a case study completed by North Carolina Advanced Energy Corporation that looks at what is the best insulation method for closed crawl spaces. Take a look at their findings and learn what kind of energy savings are associated with both fiberglass and foam board insulation methods.
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This result makes sense. For the first year, the house with insulated crawlspace walls and no insulation to the floor is effectively making the entire crawlspace floor as a thermal mass, which helps regulate the temperature. At first, the crawlspace ground will be colder than room temperature, so it will help with cooling and hurt heating. Over time, the crawlspace ground will become closer to room temperature and be less of an effect. Even with these results, encapsulating the crawlspace is way better in the initial cost, short term, and long term.
Great observation. Thanks for sharing.
Great video with data-based discussion. In my opinion, this study needs to be updated to represented three factors that have or are becoming more common in build methods. One factor is the air and water sealing apply to external sheathing. During the time of this study, air sealing the sheathing was an uncommon practice. The second factor is the house sheathing standards are beginning to require foam insulation backing. In the North Carolina region, R5 sheathing is slowly becoming adopted to new builds and complete rebuilds. The third factor is time. This study represents one year. It would be a more complete picture if this was a 10 or 15 year study. Fiberglass in an open cross space does not have the same insulation value at year one compared to year ten.
Great information as always
First I want to thank Crawlspace Ninja, especially Michael for introducing me to Crawlspace Encapsulation. Before encapsulating my crawlspace we had a lot of moisture problems, leading to mold on the joists. As well as having rotted sill plates in areas, as well as band board. My son was diagnosed with Beckwith-Wiedemann syndrome just before his birth. This syndrome though it is very mild in consideration to others out there, can contribute to breathing difficulties. (Which he had) and after stumbling across this channel, and hearing about all the benefits that it can do as far as cleaner breathing air in the home, my wife and I made the decision to hire a contractor as CSN wasn’t available in my area. When I hired them they had their own way of doing things. But after hearing from what I had to say as far as how you guys do it. They modified their procedure to the way I wanted it done. And long story short, my son is no longer on oxygen. His coughing has tremendously improved. And he is nine months old now and doing well! So thank you very much for making these videos! Sorry for getting a bit off topic there. But one question I have (My encapsulation was done with foam walls no subfloor insulation.) Do you know if the duct system was ran in the Crawlspace in these homes or did they run in the attic? Out of curiosity, if they were ran in the Crawlspace would that have helped with energy consumption in the winter time as it would have helped heat the Crawlspace and retain heat? Thanks again!
Wow, that brings tears of joy to my eyes. Praise God and wow, that is amazing. Thank you so much for sharing. I would love it if you ever want to come on our channel and share your story. This is why we do what we do...Thank you so much! The crawl spaces that were examined had no duct-work in them from what I read in the study. I really hope they will do more research. I don't remember reading if it said where the ducts were located but I am assuming the attic.
Great food for thought for my new build in the VA mountains. Much appreciated!
Glad it was helpful!
30 years in the industry in Ohio. The formula for a crawl is to encapsulate/condition by installing visqueen on the floor, insulate walls/rim joists (R19 min or closed cell foam spray even better), provide heat duct and return air to the crawl, and make sure everything is taped with a quality tape that won't peel over time. No insulation in floor. You'll thank me later.
This is very helpful! Thanks great. Have a good long weekend!
Way Hi Thank you so much !
Good report Michael! Good data for mid South applications.
Thank you!
Great video. Definitely learned a lot
Thank you!
Thank you for sharing that data and for being honest about encapsulation. Most companies doing C.S. encapsulation are intentionally misleading or they price gouge the homeowner. i just wish Crawl Space Ninja was in Southern West Virginia. Great video!
Thank you so much. We are hoping one day to have a location in your area.
Thank you for the information I'm about to start my crawl space project I will get back with you on how it went. Boy do I hope it goes well.
Keep us updated!
I live in Virginia and after doing research, I decided to go against the grain. I am putting borafoam on my walls in my crawlspace, but I am also putting R38 fiberglass insulation back in the joist as well. After watching this video, it seems the way I went was the best way to go. I am doing the work myself, so its only the cost of materials. I went with the R38, because when I purchased it, it was cheaper than R30. I know its an overkill, but its my money and my time. I am also putting 20 mil vapor barrier down as well. All in all, I will get my investment back long term in energy savings.
Sounds great, let us know if you see some major energy savings and/or comfort improvement
Another thought too, is wind averages for the site of each of the house. Some homes placement results in passive solar gains/loses. Just as wind can create some really strange heat losses/gains. But each home is different, and this is why you should thoroughly investigate all options to maximize your energy savings.
Great point, thank you for sharing.
Great video
Metro Detroit here - non-scientific data point for you. I purchased my 1960-built house in 2018, it had the plain vented crawlspace (about 432 sqft) with subfloor insulation (I don’t remember the R value) and a vapor barrier on the dirt floor. 4-foot concrete walls on the exterior three sides; entry is from inside the house.
My biggest worry was the pipes freezing in winter; on the coldest day of the year in Jan/Feb 2019 when it was around -11 F, the kitchen faucet pipes froze for a few days but thankfully didn’t burst. I put a wifi thermometer/humidity sensor in the crawlspace just below the faucet, at least to be able to watch it.
Later that year I hired a company to encapsulate (this was before I found your channel). They took out the old vapor barrier and insulation, installed a new thicker vapor barrier, 2-inch rigid XPS foam insulation on the exterior walls, and vapor barrier with tape sealing over that. They also put fiberglass into the cavities in the rim joists. Later on a friend’s advice I cut up some of the leftover foam to block the vents from the inside.
All that together seems to have helped to keep the crawlspace from going below freezing. I’ve not had my pipes freeze since then; today was single-digit weather but my sensor shows that the temp inside the crawlspace only dropped from 53 to 47 degrees over an 11-hour period.
The floors above are still cold, but I have little to no fear anymore of the pipes freezing. And it’s very dry in winter, usually in the 25-35% range. I was even able to close the baffles on the ducts that open into the crawlspace (but they’re old so some air still gets out).
In summer it does still get very humid; I have a dehumidifier with a pump and drain tube leading through the interior wall into the utility room drain. I also experimented with using a crawlspace vent fan in the summer; it helped but wasn’t as effective in high humidity periods.
So I’m basically Team Wall Insulation after all of that. I did start noticing a year or two ago that after it snows, an area of the concrete extending about 2-3 feet from the house seems to clear on its own. That tells me some heat is still getting out , most likely through the sill joists. I’m wondering about going back in and replacing (or adding to?) the fiberglass batt insulation with the rigid foam in each cavity, either pressed tightly into place, or maybe loose fit and then sealed with caulk or Great Stuff around the edges (I’d seen that on a different channel).
Sounds like you did a great job making the crawl space stay above freezing even during very cold temperatures. I am glad to hear the pipe freezing issue has been corrected. I imaging more insulation around rim joists will help along with air sealing that sill plate to keep drafts out or your heat from leaving the crawl space. Great job and thank you for sharing!!
Removing the floor insulation allowed heat from the space above to radiate downward via the subfloor, which helps keep your pipes from freezing.
Watch out for condensation on the rim joist when you have fibrous insulation in that location.
The testing occurred in Princeville , NC which had been nearly completely destroyed by Hurricane Floyd. In some places, original homes there were inundated by upwards of 30 ft of flood waters after a major failure of the levee system there. Hence the ability to have all these identical houses in one distinct area.
Thank you for letting us know.
Thank you
Pretty interesting, I honestly would have figured the savings to be higher for either over control. After the cost of materials and labor that is a huge time frame for ROI. It seems to me though, the ideal situation would be to have both wall and floor, but in the summer use adjustable baffles/dampers to divert your source of return air to be from the basement/crawlspace so you can take advantage of that cool earthen air. Not sure if you'd want to have that basement/crawlspace air supplemented with a dehumidifier. Once you start dehumidifying that adds a whole other variable.
Thank you for sharing.
I had my 2700 sq. ft home encapsulated in 2019 immediately after I bought it and both my wife and I noticed how cold the house felt in the winter. I wished I had waited and compared my first year in the home with the R-19 fiberglass insulation to after encapsulation. I had full trust in Crawl Space Ninja so I put my "winter cold home" thinking to rest, assured that my wall insulation was best. Well!? . . . this video seems to validate my winter/colder floor previous thinking. I'm in Western N.C. and it just got down to 8 degrees with a minus zero wind chill. It can get cold in the Carolinas. Wonder about some foam board in-between the floor joists, or even a lesser R rated/cheaper fiberglass insulation.
Do you know what the crawl space temp was during the 8 degrees outside?
@@CrawlSpaceNinja No, but usually is within a few degrees pf the inside house temp, cooler. Just yesterday, I insulated the rim joists, but opted for 2” green board, R-10.
Another factor to consider in colder climate areas, is that the frost line is much deeper. I live and build in NC now but lived most of my life in VT. A crawl space in places like VT would be at least 4' in the ground and with ground adding a insulating factor wall insulation would be much better choice.
Thank you for sharing
Hello everyone, I have published a book, "Crawl Space Repair Myths-Busted: Avoid Bad Advice, Bad Decisions, & Bad Repairs" on Amazon if you'd like to check it out. amzn.to/3Hhy4lL
I live in tulsa oklahoma. I put reinforced vapor barrier on floor and walls like you teach. I insulated rim joists with foam board and sealed with great stuff then put rock wool over the foam board. Should I do the wall insulation and also floor insulation in oklahoma?
Many located in super cold climates have suggested floor and wall insulation to be a good idea, if there is a heat source in the crawl space. I hope that helps and thanks for watching.
How do you deal with the code requirements related to fire barriers? All building code I have seen requires a fire barrier on the rigid foam that would general be installed on the walls.
The foamboard we install has a fire rating stamped on each board that our local codes enforcement allow. Local box stores may have something similar.
Thanks for the video. Very informative video. I'm struggling in getting data on if I should upgrade my insulation in my ~23 yr home in NC? Ventilated crawlspace (1st floor ~2500 sq ft) floor joists 2x10 16 OC insulated with R19. Insulation is showing its age and was not sure if there would be any ROI with replacing/upgrading floor insulation.
I have spoken to many about rockwool but not sure on ROI either because it tends to be more expensive than fiberglass but better in moist areas as a subfloor insulation. If you do remove/replace, I'd recommend you air seal all penetrations in subfloor and rim joist as part of the project. Hope that helps, thanks for watching.
Curious to know if the performance would favor sealed with wall insulation in winter months with humidity control
Good question. We see crawl spaces tend to be less humid in winter due to house heat and natural tendency for cold air to have less grains per pound of moisture.
So… floor joist insulation for Winter energy savings…and foundation wall insulation for Summer energy savings?
Yes, great summary.
Cooool!
I have a quick question. I live in AZ and we are building a cabin in the white mountains. 6,000 feet elevation. Summers are pretty mild (we are not putting in central air) and winters can get down to 0* F. We have a crawl space with a vented stem wall. My main concern is pipes freezing during the 2ish or less months that it does drop below 32 at night. Our plumber recommended not insulating the floor so the ambient heat from the house would keep the pipes from freezing. Would using wall insulation help with that. We've been getting estimates and all of them want to spray foam the sub floor. Thanks.
For questions like that please submit a Ask a Ninja form - crawlspaceninja.com/ask-a-ninja/
So my home has subfloor insulation already. We live in VA. I can't decide if I want to insulate the foundation wall or just encapsulate without wall insulation.
Did you decide which way is best for you?
I recenally had my crawl space ecasulated with a dehumidifer and sump pump. However I don't have any insulatoion. They said it is best to leave one vent open for ventlation. Is that correct or should I close off the last vent?
Also do you know how much I'd save by adding insulation to the walls right now it is just the poly on the walls. I am in Georgia if that helps.
Hey! Leaving one vent open and having a foundation vent fan is a great idea to let the crawl space breathe and dehumidify more efficiently. For more information feel free to submit a Ask a Ninja Form - crawlspaceninja.com/ask-a-ninja/
If I close up an open crawl space in Cincinnati and decide to go with insulating the wall, should I seal and insulate the rim joist as well?
Hey Chuck, we do recommend insulating the rim joist. Here is a video that goes into more detail on why: czcams.com/video/N6yE33FT8Pw/video.html
Do the energy savings related to sealed crawls in the study take into account the energy used by dehumidifiers in the sealed crawls?
Yes!
I have a side room on my house. The attic could use more insulation but the floor in the crawlspace has none. I'm on a limited budget which should I do first to keep the room warmer (add more in the attic or insulate the floor)?
I would air seal attic, then air seal subfloor of crawl space, if there was money left over, add more attic insulation if less than R38, then crawl space. This can air seal: diy.crawlspaceninja.com/spray-foam/
We bought a used home in Texas. Built in 1952, we put insulation in the attic and the outer walls, We’re on pier beam. It’s vented with no insulation under floor. What should I do. Floor is cold in winter even with carpet. But feels good during the summer. Any recommendations?
Sounds like the insulation is not protecting from cold air. For more information and a in-depth break down please fill free to submit a Ask a Ninja form here - crawlspaceninja.com/ask-a-ninja/
So in the northeast, this house in this crawl space has a vapor barrier, insulated foundation walls with 2” reflective foam board in a sealed space no humidifier or vents (at the moment). Also it has heat/ac duct going to a floor register above and water lines for stacked washer & dryer; would you recommend insulating the floor joists? Cold floors stink in the winter here in the northeast. What do you recommend ninja? 👍🏻
Possibly but keep in mind floors will not be "warm" to your feet unless they are the same temp or higher as your body. They may feel a bit warmer by adding subfloor insulation. I lived in Boston and it seemed more insulation was better.
So probably makes sense if you are in the 4A or 5A areas of the energy star chart should probably do both. I had bad floor insulation that needs replaced and was going to put in R30, but I think the R19 (which is recommended here in 4A in Maryland) with the wall insulation should do best.
Good luck!!!
Interesting. As a newbie to the topic, it would have been most helpful for you to show images (or even a better a video) of each of the three options.
Thank you for the feedback, we will try to show more images in the future.
With our new build home here in Clarksville, it has subfloor insulation. If i understand you correctly, we would benefit from wall insulation. Plz advise.
From my understanding, not really. The benefits of wall insulation come in the summer, as the house benefits from the heatsink effects of having an basement/crawlspace that is not thermally insulated from the rest of the house. If you already have subfloor insulation then you aren't gonna get that benefit if you decide you add wall insulation because you're insulated from the area underneath the floors. To maximize you would want to remove and relocate that insulation to the walls if possible. But look at the cost and ROI. Super marginal at that point to even worry about, unless you want to do the labor yourself and if you're able to reuse the insulation you already have installed. But I mean look you're talking about a 3% difference overall, which is statistically insignificant.
You could see a benefit of wall insulation if your crawl space is sealed. No benefit if it is not and you are in a climate that runs AC more than heat.
Should you take down existing R-19 fiberglass batts in subfloor or just leave them in place? I plan on doing 2” foam board insulation to rim joist and block wall. That is also along with E80 Aprilaire and foundation vent fan.
If the batts are hiding or creating a moisture problem or preventing the drying out of the subfloor then yes. Also we remove subfloor insulation when addressing mold. Hope that helps.
good job.
Thank you! That means alot!
@@CrawlSpaceNinja Sure thing, hope all is well, be blessed.
could the difference in winter saving for r19 be better because the floor insulation would partially help seal that critical rim joist area whereas the ridgid foam would not cover that area at all. I would be interested to see if that study included a rim joist insulation or if r13 wall insulation with rim joist air seal outperforms in all climates.
Great point, not sure but we do encourage a crawl space's rim joists be insulated and air sealed.
I read through the article and looked at their charts, grafts and drawings. The insulated walls also had the rim joists installed with spray foam 2-3” thick and all air penetration points were sealed.
Crawlspace Ninja:
I am encapsulating my Crawlspace, in climate zone 5.
Do you think i still need insulated ducts or can i safely use standard flex duct?
We suggest checking local codes!
I live in NC. So can I use wall and subfloor insulation?
Yes, you can use both if your crawl space is sealed. If it is vented, foundation wall insulation is not useful.
I'd be curious to see what type of flooring they had on the interior of the house. We found that hardwood floors and tile houses benefit from subfloor insulation more than you would expect. Our best guess (no study commissioned) from conversations with home owners is because people don't like their feet to be cold in the winter. If the floor is cold they crank up the heat. But in the summer they don't crank down the AC to make the floor cold. I have a friend in Tennessee on a farm, he cringes every time his wife and daughter turn on the heated floor in their bathroom. Especially in the summer when the AC is set so cold they have to run the floor warmers! ; )
I agree, there are a lot of unanswered questions. That is why I was hoping to have a rep from the study join me but they declined.
@@CrawlSpaceNinja its sad that the study's authors or representatives decided not to talk with you. It would be interesting if someone took on some of the points/questions that you and the audience have generated. We can all benefit from better insulation and sealing of our homes. It improves the quality of our life, our wallets, and our health. With todays big push by some of the "climate change authorities" you would think that any steps that we can make in reducing our electric consumption, would be broadcasted far and wide. Not only for the health benefits, or the money saving for the homeowner/rentes, but also for the decreasing the demand on the grid. We know how well some parts of the country are fairing with the issues of supplying energy to portions of their grid.
@James Harper, I have old hardwood floors in my house. They were installed over the top of diagonally laid 1 x 6's and 8's. There is nothing quite like the draft that comes through all those spaces. I contemplated insulating them, but most of the floors over the crawlspace are not in the greatest shape to begin with, and the crawlspace gets damp/wet at times, so until I address the main water issue... insulation is just another way to proliferate mold.
I am slowly saving my money to replace all the floors in the house with updated standard practices: continuous tongue & groove subfloors, and I will probably put down vinyl sheet goods in the wet areas of the house, and vinyl planking in the rest. My hope is that after ripping out the old joists and floors, to be able to have crawlspace encapsulation done under the living room & 2 bedrooms. The rest of the house has a basement. Then maybe, my feet will be warm, and my thick wooly socks and slippers won't totally be necessary, 😃
@@denisegaylord382 You're on the right track. Don't insulate until encapsulation. My house had similar subfloor and floor like yours. Previous owner did a poor insulation job with blue foam board cut to fit. He thought it was great. I pulled a few to inspect and.... Mold and rot in many places.. Crawlspace work is hard if you're not conditioned for it. Mad props to the Ninja's!
P.S. Murino wool is the best for socks! My feet do not lie. After long hours in boots, Murino saves them. 🦶🦶
@@denisegaylord382 I agree, it seams the DOE would be more interested in this topic.
Hello Crawl Space Ninja. We're in the great cold State of Michigan and is highly considering insulating our roughly 500 sq ft addition/room on the rear of the home. It sits above a nearly 3 ft high uncovered dirt crawl space with two vents. No other insulation exists, nor does pipes exist here. This room offers freezing cold in the winter months. Now, there's 1 heat register, but of course, this room isn't containing heat. For clarification, would using closed cell spray foam (or) 2" inch foam board reflective insulation be useful with adding insulation to the floors boards with R-19 rolls?
The way I interpret the data from the study. Insulation on foundation walls and subfloor may be a better option for comfort in cold areas of the country like yours. Spray foam or foamboard on walls would be your personal preference. Both have pros and cons. I hope that helps. Thanks for watching. I'd also run that question by a local reliable insulation contractor just to be certain.
had a thought to use a smart vapor retarder on the underside of joists to further reduce humidity that hits the framing. on top of vapor barrier on the floor and powered exhaust vents in the wall. any thoughts on this? currently putting down your vapor barrier in the crawlspace
I am not a fan of putting VB on subfloor, can trap unforeseen moisture and cause a mold issue.
@@CrawlSpaceNinja Was thinking certainteed or intello, ones that open in vapor permeability based on where the humidity is at for subfloor
@@KyleWolf-do2lm I am still not sure I would do that. If you decide to, please let me know how it goes.
@@CrawlSpaceNinja will do! i havent made up my mind yet. in theory, sounds like good idea, but in practice not sure
I’d love to see an updated study with the latest technology (insulation, ventilation, foundation materials).
Me too, I wish DOE was more interested in crawl spaces.
I live in Northern IL winters here can be rough
I bet they are, Thanks for sharing.
Bought a manufactured home last year, finally ripped out the carpet in the living room and replaced it with a vinyl floating floor and under that a very thick quiet mat moisture barrier. Once summer hit the subfloor under the vinyl has started warping. o_0 I am assuming the vapors can no longer escape due to the moisture barrier and is causing water damage on the subfloor causing it to warp. Before I replace the subfloor I need to figure out how to stop this from happening again... I am hoping just removing the moisture barrier under the vinyl floor will stop it... but idk.
Hey! We would love to talk more thoroughly about this. Ask your question on our forms and we will dive deep into this to do our best to help! - crawlspaceninja.com/crawl-space-help-faq/
Very interesting video man thank you for the information. I submitted a form on your site I would like to talk to you about a crawl space I’m building soon
Can't wait!
Where can I send my pics I’m ha just finished my removal of fiber bats that the installer did paper side down lol in 1980.
Hey! Submit them here DIY@crawlspaceninja.com
Based on this study, in general, north of the Mason Dixon line wall insulation would be king because of the super hot summer temperatures. In the North, subfloor insulation would win because of the really cold winters.
I wrote that before I saw the part of the video where you had your conclusion. I had paused the video. :)
Awesome!
Ever used this product? SmartSHIELD -5mm 48"x50ft Reflective Foam Core Insulation roll, Cold and Heat Shield, Radiant Barrier, Thermal Insulation - Engineered FOIL / White Film
There are tons of great products out there but no we have not used that one.
Either way, looks like the best practice is to wait until April to install wall insulation, and ride out the winter with just floor insulation in place.
Thanks for sharing and watching
A problem that might happen if you put down a vapor barrier on the ground of a crawl space is if you had pipe burst it might cause a problem if the water couldn't drain into the ground.
Hey Jeff, you're right! That is a big reason why we always install a Dranjer Drain on all of our sump pump lids, so that water can enter in from the top if necessary. Here is some more information about the drain if you're interested: czcams.com/video/G4qPrJPR0eU/video.html
So if I'm thinking of encapsulation, shouldn't I leave the fiberglass floor insulation?
Hey Ben, if you do not have a mold problem on the joists that needs to be treated you can definitely leave the fiberglass floor insulation.
I'm guessing the sealed houses with wall insulation were not a conditioned crawl spaces? if not it would be cool to see that one added to the study.
Noted!
So every home had identical HVAC systems and identical floor plan. Additionally did they monitor the thermostat settings for each home
I did not see that information in the study so not sure.
I'm in Michigan and going to try the wall insulation... see what happens
Thanks for sharing
did all these people keep the thermostat the same?
Great question, I don't know. Sorry
The big unanswered question is *why* did floor insulation-only perform better than wall insulation during the coldest winter months in this study, and was there something specific and unusual about the homes in this study, or can this unexpected result be generalized to any home.
Great question Donald, I wish we had more studies to validate your comments.
R-18 in floor vs R-18 on walls. I'm betting matched R-18 wall would outperform R-18 floor.
My theory is that the ground overall acts as a heat sink. So it would make sense that the subfloor insulation protects from the cooling effect of the ground in the winter, whereas if only the crawlspace is insulated and the subfloor is not, that creates no insulation barrier from the cold ground to the rest of the house. The benefit is that in the summer, the cold ground with an uninsulated subfloor has direct access to heat.
So really, based on the information in the video. The most optimal and energy efficient situation would be to have removable subfloor insulation that gets taken off during the summer months and put back on the rest of the year.
The sun's effect on heating and cooling costs as related to wall insulation will be affected by a house's eves and the angle of the sun to the wall and the eves. Further, as the wall is heated this way, so will be the crawl space, and so the need for floor insulation.
Thank you for sharing!
I am glad they at least pushed to run the study 12 months of the year anything less would have been pointless. What disappoints me about the study is that there were too few homes with unaccounted variables. It sounds like this study only looked at overall energy usage, not necessarily the type of energy used or how. 1. What was the preferred thermostat setting in each home? 2. Was the HVAC on a schedule or always on? 3. Were the windows always closed? 4. How often did the residents open or enter their crawlspace? 4. Were the residents keeping up with their air HVAC filters? 5. Did anyone set up Holiday Lights and was that lighting usage comparable (Pre-LED that made a huge difference)? 6. What was the age of the HVAC system? 7. Did they all have the same HVAC system? 8. Did they have guests or residents who just left lights/fans/space heaters running for personal comfort? 9. There was not have a home with sealed vents that insulated both the subfloor and crawlspace walls (Maybe we get 21% savings). 10. There was not a control with no insulation at all. 11. Was the actual ground in the crawlspace lined with vapor barrier or, was it bare? 12. If the crawlspace ground was bare, was there a difference in elevation and ground moisture?
Those look like some great questions they should have answered or considered in their study. I don't expect them to do any more studies on the subject but maybe one day they will. Thanks for sharing.
If a company as yours bids on a crawlspace job which is determined to be extensive, and the crawlspace height is 4' at most, do your workers approach the space from the crawl opening at the foundation, or cut openings into the subflooring from above? How would you pros decide?
*And again, Oregon is starving for such a service.
Usually we would use the foundation opening that already exists but we do come across the living space access from time to time. I prefer a foundation wall opening if possible so there is less risk of tracking debris, etc during the encapsulation process. The access from the living space to the crawl space can also hinder energy efficiency. It becomes direct access for air movement and unless air sealed properly, can causes the stack effect to be worse. We see this when attic access is from the living space. If attics were accessed from the outside, you would be losing less heat and AC to the attic every day. Hope that helps.
@@CrawlSpaceNinja ...many thanks.
@@mwngw You are welcome.
I "suspect" the energy improvement for vented crawl spaces during November, December, and February was due to the crawl space acting as a thermal energy battery-thermal energy is being stored in the floor of the crawl space during October. So why was January worse, because “likely” the thermal energy improvement is related to rate of change towards cold weather. So, does anyone sale an insulated basement vents and controller that I can open in October and when the outside temp is above a fixed temperature. (like above 72F in November, December, February, plus below 75F in July, Aug, etc)? I need four vents and a controller. P.S. I already use part of this strategy in my attic with a humidity sensor so I’m not letting too much moisture into my attic - same humidity sensor concept would apply to crawl spaces.
I am not aware of an insulated crawl space vent that opens nor am I familiar with one that is not insulated that truly opens via humidistat or temp sensor. Just those metal coil ones that have been around forever. Sorry.
Thanks for your reply.
Trying to turn crawl spaces and basements into thermal energy storage for heating and cooling homes would be a very, very interesting research project. Even if I implemented the concept in my house, I would not have a base model to compare results with. My engineering insights suggest a designed system that turned ventilation on/off at key times might provide great energy savings (Heating & Cooling) in some heating/cooling zones. But having 12 to 24 identical homes (with crawl spaces and basements setup to test different approaches like different wall insulation and floor installation levels plus different venting strategies) to test the concept is outside my budget. Maybe Bill Gates or Warren Buffett or DOE/Hud would be willing to build 24 low income 1,600sqft homes that could be used for testing before delivery to low income people! I do have a BSEE and technical master degree and have learned that I can learn from almost anyone to build system that exceeds others.
The research paper does suggest turning Crawl spaces and possible basements into thermal storage system might be possible.
Without building dedicated hardware and software, the following hardware might be useful for testing.
• Seco-Larm SA-027HQ 365-Day Annual Timer with Two Relay Outputs
• Aprilaire 6506 6” damper
• DIGITEN DTC102Z Digital Humidity Controller
• DIGITEN DTC101 Temperature Controller
• Functional Devices RIB2421B Power Relay
• 120VDC to 24VDC converter
Retired Engineer
How about basements? Northeast.
I don't know of any basement studies for Northeast, sorry.
Did they install a dehumidifier and insulate the rim joists for the study? Surely someone online can provide data from their encapsulation results over a period of 2-3 years. I would think Crawl Space Ninja would have paid someone to provide data...
I did not read that a dehumidifier or rim joist was installed.
Sounded like repetitive humidity played a role here, but the data talks about pure energy use in units.
Interesting thought!
I want to start insulating my crawl space but it has been raining quite a bit. Should i be concerned about the possibility of trapping moisture (from maybe accidentally getting my foam wet) in-between joist and foam??
I would test the subfloor moisture levels. Under 15% is usually ok and ensure the material you are installing is dry first. It's a valid concern. I hope that helps, and thanks for watching.
@@CrawlSpaceNinja thanks for the prompt response, I'll check the moisture content and then wait for dryer weather for the work to insure im installing dry material.
@@diydadsht9785 you are welcome.
Actually, logical. The crawl space is a heat sink. In the summer, it actually acts as geothermal cooling for the house. The more effective insulation actually works against you in the summer because you lose the cooling effect of the ground beneath the house. The more effective insulation is subfloor because it actually is a barrier to the cooler crawl space. But, in the summer in a hot climate, you don't want the more effective insulation because you want to leverage the cooling effect of the crawl space. Maybe the answer is to seal the crawl space, insulate the walls, and open a vent to blow some heat into the crawl space - lotta work. Maybe the simple fix is to insulate walls in hot climates and floor in cold climates. However, the other wild card is the hours during the day power is used and the affect of teired rates based on peak demand hours. This could really skew the results of this study which only considers actually power used and not "the bottom line" - that would be cost. In the winter, more power usage is in the evenings and at night, which is generally at a lower rate. In the summer, more power is used during the day and is at a higher rate. So, it may be best, in all instances, to insulate just the walls based on cost. Or, in the case of my cabin, only the floors because I don't cool my cabin in the summer because the ambient temp hardly ever gets to 90, but it gets to zero in the winter.
Thank you so much for sharing.
Our crawlspace is open
Thank you for sharing and watching.
I bet if the R-13 wall insulation had been R-18 instead, it would have done better than floor R-18.
Yes, but our walls in south are only designed for r13. Thanks for sharing and watching.
In other words the energy savings with the sealed crawl space will never be able justify the cost of sealing the crawl space.
People don't seal crawl spaces or attics, usually based on energy savings alone. There is no ROI to pay for the work. Most do it to improve indoor air quality and comfort.
FYI, you don't need their permission to share information from this study, or from anywhere.
Good point :)
Have to be suspect about a report 18 yrs, Do this report again with new building products and techniques also it should be regional only
I agree, building practices have changed significantly. I don't think they are doing a new study. It would be nice if the DOE would do more studies like this in different climates.
Definitely not a large data set. If a couple of houses in any of the three sets of four houses used in the study kept their thermostats higher than average in the winter or colder than average in the summer, could definitely skew the results.
Good points, thank you for sharing. It would be nice if more research was done in this area.
This study forgets spray foam…. :(
I agree, would have been nice to see subfloor penetrations sealed. or do some homes with spray foam walls and some with foam board.
Ah I think your interpretation of the data during the colder months is wrong. There’s essentially no difference between all of them. The error bars overlap each other essentially every single case. There’s no statistical difference.
Thank you for pointing that out.