Whole house fan

Discussion in 'The Garage' started by Yinzer Moto, Jul 12, 2019.

  1. Yinzer Moto

    Yinzer Moto aka: trailer Rails Supporter

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    Does anyone have any recommendations? Quiet and efficient are at the top of the list for this project.

    All houses are a little different and our house is somewhat unique. It is a raised ranch, one floor living with a basement/garage below. The main living area it about 850sqft. Half of it has a vaulted ceiling (main living area) and the other half is 2 bedrooms and a bathroom.

    This past spring I had 5 huge trees removed from around the house as they were threatening the house and our safety. We live on top of a hill and I could see those trees swaying 10-15 each way in high winds. With the removal of those trees, now the house is warmer than it has been in the past. In the past, we might have needed air conditioning a couple days a year, this year it has been on 10 times or so. A small window unit is all that is needed to cool the place down.

    I am thinking that I am now getting more heating of the roof surface than before, because of the tree removal. My plan is to move more air through the attic space, doing what I can to force some air movement through the vaulted ceiling area.

    I am looking at installing a 8” duct booster fan to draw air from the top of the vaulted ceiling area, inside the living space and blowing it into the attic. Moving warm air from the living space into the hot air of the attic space. I would suspend the fan from flexible strapping and use flex ducting in an effort to reduce noise.

    This fan would have the house air exchanged about 7 times an hour. The attic volume being much less, it would be exchange at a much higher rate.

    https://www.amazon.com/Vortex-711-C...780&s=gateway&sprefix=Whole+h,aps,147&sr=8-54

    E6A30554-1D0E-4344-89F8-EEAF28C8BD70.jpeg
    #1
  2. gmiguy

    gmiguy You rode a what to where?

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    I'm not clear what you're trying to accomplish by moving air from inside the living space to the attic. That air will have to be made-up from someplace, likely in the form of warm outdoor air. What's the advantage of exchanging cool indoor air for warm outdoor air?

    In your situation I would be more inclined to encourage air exchange between the attic and the outdoors, while keeping the cooler/conditioned indoor air inside the occupied space. This way you keep the attic at ambient (instead of ambient+) and thereby reduce heat transfer from the attic into the living space.
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  3. Yinzer Moto

    Yinzer Moto aka: trailer Rails Supporter

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    Are you familiar with whole house fans?

    The idea is that there are times of day when the outside air is cooler than the indoor air and the attic air is very hot.

    Typically, they are run in the evening hours.

    Our indoor air is not cool or conditioned.

    I agree some form of powered attic vent might work also.
    #3
  4. Yinzer Moto

    Yinzer Moto aka: trailer Rails Supporter

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    Here is an article that explains how a whole house fan works.

    https://www.energy.gov/energysaver/home-cooling-systems/cooling-whole-house-fan

    In our climate, the windows and doors of the house are open almost 24/7 for over 6 months a year. As I mentioned, we need an air conditioner a handful of times a year.

    A little ventilation in the evening might make up for having the trees removed.
    #4
  5. gmiguy

    gmiguy You rode a what to where?

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    OK, got it. I thought you were approaching "more AC use" as a given and were looking to improve its efficiency. What you described makes sense if you plan to continue using window/door ventilation as the primary approach.
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  6. Dirt survivor

    Dirt survivor Adventurer

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    Love my fan , turn it on in the afternoon and it sucks air in through the windows and into the attic, then out through the attic vents cooling the whole house and uses very little electricity
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  7. Wentwest

    Wentwest How's that work?

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    My efforts would be to put a somewhat larger fan in the gable end of the enclosed attic, maybe thermostat controlled with a manual override option, and vents that allow air to be drawn from the vaulted area and from the bedrooms below the attic. Those vents can be passive, with draft control shutters so the airflow is one way.
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  8. NorskieRider

    NorskieRider Long timer

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    Consider adding more insulation to your attic to prevent the heat from seeping into your living areas.

    My father in law (in MN) had whole house fans installed in their last two homes, they are awesome, and reduces the number of days they run A/C.
    #8
  9. Sonny S.

    Sonny S. Long timer

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    One of our buildings at work has 4-48" roof exhaust fans. Once outside temps warm up I have them mandatory on late afternoon to morning. The inside air temp drops to about the outside temp by the time we come in at 6am. Real nice way to start the day and better than the stale 85-90* temps it can reach mid day. Of course we have louvered air intake vents to match the CFM of the exhaust fans.
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  10. dravnx

    dravnx Been here awhile

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    I installed a gable mounted exhaust fan in my last house. It worked really well to cool the house down and was not very noisy. I don't remember the brand as it was something I picked up at the local home improvement center. It was thermostatically controlled. My present house has a fan mounted in the hallway that exhaust into the attic. I installed a couple of extra vents on the roof. This fan moves much more air but is also much louder. The good thing about this fan is that I only have to run it for a few minutes to completely exchange the air in our 1400 sq ft house. We keep our well insulated house closed up during the day and it stays comfortably cool. There is usually about an hour a day when the house gets warm but the outside temp is not cool enough to run the fan. When the outside temp gets lower then the inside temp, we run the fan for a few minutes. Open a couple of windows and the air is exchanged in a few minutes.
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  11. vtduc

    vtduc Been here awhile

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    I had an attic fan in a former house and it worked a treat. My current house does not have an attic, but I can open the door to our walk-out basement and prop a box fan against an open screened window on the second floor and it helps tremendously (not the most efficient setup, but there it is)
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  12. the_gr8t_waldo

    the_gr8t_waldo Long timer

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    rather than bolt a gable fan, my refence would be to suspend the fan/motor so that minimal noise would be transmitted to the structure. so sleep is not disturbed by an all night motor bolted in and running, would. I might even look into a d.c. fan motor , If I had excess $ that needed drawing down.
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  13. Yinzer Moto

    Yinzer Moto aka: trailer Rails Supporter

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    Yes. That was the plan, to suspend the motor with plastic strapping or something similar. Connect it with flex ducting.

    The motor I picked out would have an air exchange rate of 7 per hour. Is that too low?

    I think many whole house fans are more than that. They create a nice breeze moving through the house. Traditional fans are very loud and I am trying to engineer a solution that is quieter but still effective.
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  14. Project84

    Project84 I can haz adventure?

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    You mentioned only running a small window unit 10 times so far this year. Consider yourself lucky! (Wednesday in my zipcode the heat index was 100*F)

    I'd take a hard look at the cost payoff before jumping into this project. If you're windows and doors are open 6 months of the year, presumably you've got 3-4 months of the year where it's comfy enough w/o opening anything and w/o running heat (here in KY not far from you that's basically March/April and then Oct/Nov) so you're only looking to cool the house 2 months of the year, July and August.

    Why not just run the A/C and pay the $30/mon extra in utilities?
    #14
  15. Yinzer Moto

    Yinzer Moto aka: trailer Rails Supporter

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    Excellent question. I enjoy open windows and the sounds of birds chirping. Our house is small, it makes it feel larger by opening up. It is just personal preference. The bedroom is so small that there is no furniture in it, just a king size bed. Then there are French doors that open to the deck. Open them up and it feels like we are camping.
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  16. arkansawyer

    arkansawyer Long timer

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    The house I grew up in had an attic fan. It was belt driven. The fan was large but turned low rpm. Moved air without a lot of noise.
    Wish I had that in my present house.
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  17. SquatBirdJunior

    SquatBirdJunior Special Snowflake

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    Check the insulation, if hot in the summer, is it cold in the winter?

    Any air movement in the attic will help. Does it have enough roof vents? Is the humidity high?

    The house I'm building is just the opposite, don't want to bring in 100+ degrees, but still the same concept with a Balanced Ventilation system(ERV).

    And how hard is it going to re-do the duct work in the fall?
    #17
  18. Yinzer Moto

    Yinzer Moto aka: trailer Rails Supporter

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    It is not bad in the winter. The insulation could be better. The ceiling is only r19. Venting is good. Humility is definitely not low.
    #18
  19. Wentwest

    Wentwest How's that work?

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    Gotta work on that humility index.
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  20. Yinzer Moto

    Yinzer Moto aka: trailer Rails Supporter

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    If it would quit raining so much the humidity would improve. I refuse to give this view and up being able to leave the windows and doors open to the house. They stay open until temps drop into the 40’s.

    679A9B5D-1DDC-4C39-A547-EB7E4E2ABEE1.jpeg

    By starting this thread, I was hoping to find someone who has designed a quieter whole house fan and maybe could offer some advice. Whole house fans are popular in this region but they are typically solid mounted to the framing in the ceiling. They sound like a Cessna on takeoff.

    Edit: this fan looks quiet and efficient. My concern is if 700cfm is enough.
    #20