I bought a QuietCool fan after watching your first video, and I like it a lot. I have the QC fan intake in the garage, and a gable exhaust fan at the other end of the house kinda like yours. I also installed them into Smart outlets and installed temp sensors in the attic, garage, and outside, so they are controlled automatically with the temps. In Arizona it gets hot fast, and on a typical mid summer 110 deg day my attic temps got close to 150 without the fan. Now they are 125 or so mid day, and if I crack the garage door, the temps get down to 115-120. I want to install a vent that I can open and close in the garage, so that I don't need to crack the garage door. Another benefit to the fans is I can open the inside garage door (laundry room) and crack windows, and then it pulls from those windows very fast and cools down the house at night during the cooler months. So I want to install another controllable vent at that door as well.
QuietCool recommends 1 square foot of intake vent area for each 750cfm of fan volume. Your AFG SMT ES-3.0 does 2800cfm on high speed, so 2800/750 = 3.75 square feet of intake PER FAN. And now, since you've installed 2 fans, you need 3.75 + 3.75 = 7.5 square feet of intake. There is NO WAY the tiny holes in your soffit vents add up to 7.5 square feet!!! Also, as you pointed out in the previous video, the louvers of the gable vent might be causing inefficiency as the fan tries to push the air out. And, if the diameter of the fan is larger than the width of the gable vent.....well, there's another inefficiency. So, you are choking your fans on the intake and choking them on the exhaust. This is the reason I decided to go with the QuietCool roof-mounted fan rather than the gable-mounted fan. This allowed me to utilize my 2 gable vents as they gave me the proper amount of intake vent area. As it is right now, your 2 fans are playing "tug of war" with each other, and you are not moving/removing much air as you are creating negative pressure in the attic. And, unless you have EVERY attic penetration (ceiling lights, bathroom exhaust fans, electric/cable/telephone wire penetrations) air-sealed, the negative pressure will suck conditioned air out of each and every one of those leaks. My 3 suggestions for you are: get rid of your fixed louver (wood or plastic) gable vents and replace with electrically operated louvers of at least 16"x16" to match the 16" dia of the fan AND disassemble the "west-side" fan, drill 3 new holes and re-mount the fan motor & bracket so it is blowing INTO the attic AND air-seal every attic penetration (if you haven't already done so). Now the 2 fans will be working together in a "push-pull" setup that will move LOTS of air.
Your post had me questioning my square footage of ventilation. Because I was doing a short video, I did not completely describe all of my attic ventilation. After measuring all my ventilation in detail, I have a total of 8.5 ft.² of ventilation which is 1 foot over recommended for those 2 fans The triangular area of each gable vent is more than enough for adequate airflow. I built a box around the triangular area which increased the exhaust area by threefold. The louvers probably don't impede the airflow by much. It only just forces it slightly downward. This keeps the rain from coming in the attic. If I remove those louvers my attic would become saturated in a strong wind and rain combination. That's why I did not remove anything. The set up works quite well. I did completely seal my attic space as you suggested, and I probably sealed to overkill because I even insulated between the drywall and the 2x4's. I would definitely never reverse a fan and have it pull air into my attic because when it rains, I would then pull in the water into my attic especially if I remove those louvers that keep the rain out. That would damage the motor in the fan and soak my attic. Do you have enough enough airflow in your attic with those roof mounted fans? When I looked into it, it wouldn't have changed my airflow that much so I didn't go that route. What is your outside temperature in comparison to your inside temperature at the peak of your roof? The difference in my attic and the outside air averages about 10 to 15° warmer in the attic. On my hot side of the attic I've never had it run more than 20° difference.
Please watch my first video on the quiet, cool fans czcams.com/video/vKgu-LDAKUQ/video.htmlsi=TXukaNI_DxaiagXK
Thanks for the tips!
I bought a QuietCool fan after watching your first video, and I like it a lot. I have the QC fan intake in the garage, and a gable exhaust fan at the other end of the house kinda like yours. I also installed them into Smart outlets and installed temp sensors in the attic, garage, and outside, so they are controlled automatically with the temps. In Arizona it gets hot fast, and on a typical mid summer 110 deg day my attic temps got close to 150 without the fan. Now they are 125 or so mid day, and if I crack the garage door, the temps get down to 115-120. I want to install a vent that I can open and close in the garage, so that I don't need to crack the garage door. Another benefit to the fans is I can open the inside garage door (laundry room) and crack windows, and then it pulls from those windows very fast and cools down the house at night during the cooler months. So I want to install another controllable vent at that door as well.
Wish I could hear you better :-(
QuietCool recommends 1 square foot of intake vent area for each 750cfm of fan volume.
Your AFG SMT ES-3.0 does 2800cfm on high speed, so 2800/750 = 3.75 square feet of intake PER FAN. And now, since you've installed 2 fans, you need 3.75 + 3.75 = 7.5 square feet of intake. There is NO WAY the tiny holes in your soffit vents add up to 7.5 square feet!!!
Also, as you pointed out in the previous video, the louvers of the gable vent might be causing inefficiency as the fan tries to push the air out. And, if the diameter of the fan is larger than the width of the gable vent.....well, there's another inefficiency. So, you are choking your fans on the intake and choking them on the exhaust.
This is the reason I decided to go with the QuietCool roof-mounted fan rather than the gable-mounted fan. This allowed me to utilize my 2 gable vents as they gave me the proper amount of intake vent area.
As it is right now, your 2 fans are playing "tug of war" with each other, and you are not moving/removing much air as you are creating negative pressure in the attic. And, unless you have EVERY attic penetration (ceiling lights, bathroom exhaust fans, electric/cable/telephone wire penetrations) air-sealed, the negative pressure will suck conditioned air out of each and every one of those leaks.
My 3 suggestions for you are: get rid of your fixed louver (wood or plastic) gable vents and replace with electrically operated louvers of at least 16"x16" to match the 16" dia of the fan AND disassemble the "west-side" fan, drill 3 new holes and re-mount the fan motor & bracket so it is blowing INTO the attic AND air-seal every attic penetration (if you haven't already done so). Now the 2 fans will be working together in a "push-pull" setup that will move LOTS of air.
Your post had me questioning my square footage of ventilation. Because I was doing a short video, I did not completely describe all of my attic ventilation. After measuring all my ventilation in detail, I have a total of 8.5 ft.² of ventilation which is 1 foot over recommended for those 2 fans
The triangular area of each gable vent is more than enough for adequate airflow. I built a box around the triangular area which increased the exhaust area by threefold. The louvers probably don't impede the airflow by much. It only just forces it slightly downward. This keeps the rain from coming in the attic. If I remove those louvers my attic would become saturated in a strong wind and rain combination. That's why I did not remove anything. The set up works quite well.
I did completely seal my attic space as you suggested, and I probably sealed to overkill because I even insulated between the drywall and the 2x4's.
I would definitely never reverse a fan and have it pull air into my attic because when it rains, I would then pull in the water into my attic especially if I remove those louvers that keep the rain out. That would damage the motor in the fan and soak my attic.
Do you have enough enough airflow in your attic with those roof mounted fans? When I looked into it, it wouldn't have changed my airflow that much so I didn't go that route. What is your outside temperature in comparison to your inside temperature at the peak of your roof? The difference in my attic and the outside air averages about 10 to 15° warmer in the attic. On my hot side of the attic I've never had it run more than 20° difference.