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Does anyone use a powered attic fan?

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[OP]
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Aug 11, 2011
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Does anyone use a powered attic fan?

I have a one that's never been used - but need to run some power to it from a wall switch or a thermostat.
I'm getting insulation/baffles/soffit work done to help with ventilation so wondering if an attic fan is even needed?

And then of course i'm thinking of why not get a solar powered one to help energy bill out :D
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Feb 11, 2007
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MikeTO2 wrote: I have a one that's never been used - but need to run some power to it from a wall switch or a thermostat.
I'm getting insulation/baffles/soffit work done to help with ventilation so wondering if an attic fan is even needed?

And then of course i'm thinking of why not get a solar powered one to help energy bill out :D
You need to calculate the CFM requirements for your roof and determine if your existing passive vents are enough, or if you need the powered vent to meet the requirement.

My poorly ventilated attic :(
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[OP]
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engineered wrote: You need to calculate the CFM requirements for your roof and determine if your existing passive vents are enough, or if you need the powered vent to meet the requirement.

My poorly ventilated attic :(
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oo what gizmo is that? Heat radar?
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Sep 13, 2016
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MikeTO2 wrote: oo what gizmo is that? Heat radar?
Thermal camera.
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Apr 18, 2005
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MikeTO2 wrote: I have a one that's never been used - but need to run some power to it from a wall switch or a thermostat.
I'm getting insulation/baffles/soffit work done to help with ventilation so wondering if an attic fan is even needed?

And then of course i'm thinking of why not get a solar powered one to help energy bill out :D
I have been looking into attic fans.. but never found good info here in Ontario as they dont seem common as it's mostly passive cooling..

But in summer the 2nd floor is almost 3-4C warmer than the main floor. I compensate by running the bathroom fans to move air upward.

If anyone finds attic fans let me know.
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Dont know anyone in a residential house with a electrically powered vent, plenty do have roof vent passive whirlybirds.

If your roof has adequate venting I wonder if it can save money in the summer for your AC needs. Obviously can control it with a thermal switch of some sort so it turns on in the extreme heat and stays off when cool or winter.
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TLSRULZ wrote: I have been looking into attic fans.. but never found good info here in Ontario as they dont seem common as it's mostly passive cooling..

But in summer the 2nd floor is almost 3-4C warmer than the main floor. I compensate by running the bathroom fans to move air upward.

If anyone finds attic fans let me know.
Making sure your attic is air sealed and insulated to R60 should be the first thing you do. And you should be able to get enough air flow with passive vents, you just might need more of them. Then you don't have to worry about them failing like elective vents.
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Oct 22, 2016
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Their are now solar power roof vents. I have not used them so I do not know how effective it is. If they are good, it would save on electricity hookup.

For Whirly bird (turbine) vents, not a big fan of them, as I have seen them fly apart, and having a moving vent like this (at least on the West Coast), in high winds, I always felt was a poor idea.
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Apr 18, 2005
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engineered wrote: Making sure your attic is air sealed and insulated to R60 should be the first thing you do. And you should be able to get enough air flow with passive vents, you just might need more of them. Then you don't have to worry about them failing like elective vents.
Yes did all that.. sealed and at R60. Will have to see in a few years when roof needs replacement if we need more vents.

Also run the furnace fan at least 15min every hour for circulation ... and verified that all my air returns are pulling air back...

It's just the 30+C days where it gets hot upstairs and for sure being able to vent some of that heat will help... for now the bathroom exhausts work well to do this ..
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TLSRULZ wrote: Yes did all that.. sealed and at R60. Will have to see in a few years when roof needs replacement if we need more vents.

Also run the furnace fan at least 15min every hour for circulation ... and verified that all my air returns are pulling air back...

It's just the 30+C days where it gets hot upstairs and for sure being able to vent some of that heat will help... for now the bathroom exhausts work well to do this ..
The problem with exhausting the warm air, is that it will bring in outdoor air to make up for it, so you maybe making the house warmer if it's warmer outside.
If you want to improve cooling, try spraying down your AC outside. It will improve the efficiency and cool your house faster. I got a 2C reduction in AC coil temps by doing that and have the AC continuously misted with water when I need extra cooling.

FLIR shot of the my furnace HVAC where the A-coil is located.
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TLSRULZ wrote:
It's just the 30+C days where it gets hot upstairs and for sure being able to vent some of that heat will help... for now the bathroom exhausts work well to do this ..
It will always be hotter on the upper floors than the main floor as cold air naturally drops making the furnace fan work harder.

Many years ago I considered fixing a squirrel cage fan over a vent on the top floor but was afraid as I had youngsters at the time.
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Getting one vent may just suck the air out from the other passive vents. But I did get a solar powered vent and it works great in my specific use case.

I have an attached garage with nothing above it but a uninsulated roof. I replaced the passive vent with a solar one and it made HUGE difference. Summer is not so hot, winter is not so damp anymore.
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