power house vents

[Drew Cutter]

I have to replace a smash vent on the roof. I thought this would be a good time to put in a power air vents. Any down side ? solar ?

[tomris]

[RickH]

I live in a 2 story, I always regretted not getting a power roof vent, I see no downside considering how hard I see my upstairs AC unit working (two AC house).

[Oren]

In the desert, pick the solar.

-- Oren

"If things get any worse, I'll have to ask you to stop helping me."

[trader4]

There is no way to answer this question without knowing a whole lot more. Is the house in Michigan or is it in Florida? What other venting is there? Soffit vents, how much area? Other upper vents? how much area, etc. You need to look at the entire attic ventilation strategy and adequacy before deciding what approach to take. You may find that you can achieve proper ventilation with good soffit vents and a ridge vent, instead of a power fan.

[ds549]

get one sized for the square footage of the attic . power vents have really cooled down some hot houses i own. one i went a size bigger to get it cooled down. lucas

[smcjensen]

I installed a fan in one of the gable end vents a few summers ago. I also built a baffle so it wouldn't suck air into the same vent then just blow it right back out. I have other gable vents in the attic and soffit vents as well. Fan was placed in one of the uppermost gables. I did some before and after testing and the power vent brought the attic temp down about 15 degrees which is pretty significant. I'm in NC and have a 2 AC house. It makes sense that an AC unit in a 115 degree attic would have less work to do than one in a

130 degree attic. Upstairs is appreciably more comfortable and on the really hot days, the upstairs AC used to run seemingly all day long.

If upstairs AC is also a gas furnace, you need to wire the fan so that it won't go on if the furnace is on as it can disrupt the flow of gases up the flue.

[Drew Cutter]

[trader4]

If the fan has a thermostat set at any reasonable temp, why would the attic fan ever go on when the furnace is running? My attic doesn't get to 100 deg+ when I need the furnace on.

[CJT]

Just do it (wire an interlock). If you have a furnace fire, the last thing you want is for the fan to turn on and help it propagate.