Pondering an idea

[G+_Rud Dog]

Pondering an idea. From what I have read the temperatures in the attic are higher than in house temps. The solution appears to be placing vent holes either on the ends of the house or on the roof.

What if the vent on either end of my house was made larger, removing the vent and installing to larger fans. This would create a pull from one side and an exhaust on the other.

Or have both fans pulling air from the interior of the attic.

 

Thoughts?

[G+_J Miller]

I run my hot water line prior to entering my hot water heater as part of a heat exchanger.

Saves gas on my water heater for me.

[G+_Henry Curley]

You don't want to have 2 fans pulling in opposition in your attic. If you only have gable vents, pulling with 1 fan should be sufficient, though you want to size your cfm for the size of your vents so you don't burn out the fan. If you have a ridge vent you should use soffit vents and let the attic aspirate naturally (heat rises and will pull in fresh air from your soffits). If you have both gable and roof vents, it actually hampers the airflow, so generally only the air near the gables will change out, so you may need to block off either the ridg or the gables.

[G+_Rud Dog]

Henry Curley The house originally came with vents on either side of the highest point of the house. Screened vents are located around the edge of the house where the roof meets the walls.

When the tiles were replaced we had eyebrow vents added on the roof.

From what I think you are saying it is either one or the other?

[G+_Henry Curley]

Soffit / eave vents are the ones near the edge of the roof/walls. I assume by eyebrow vents you mean the vents placed directly through the roof decking? The vents near the roof line in the peak of the wall on the ends are gable vents (that area of the wall under the roof is called a gable). I would just do a test and use an outdoor thermometer in your attic and see what the temps are like, and then on a similarly sunny/warm day see what it's like if you block off the gable vents, cardboard should be sufficient for the test. How many square feet are you talking, and where are you (generally, so we know what kind of climate you have)?

[G+_David Jenkins]

Power vents work fine, as long as they can draw in outside air from somewhere, preferably across the attic. The further away the intake is (within reason) the better.

[G+_Robert Hafer]

My attic has only gable vents and a few years ago I had a solar powered roof fan installed (me crawling around on a roof is a life threatening activity). It made a big difference. I've been having trouble keeping the upper floor cool this summer which makes me think the fan has conked out. (Indeed spry young minions, darn it).

[G+_ove hatlevoll]

Also there is a question of balance, if you take out more air than you pull in, it has to replace it. You may end up with a negative air pressure in the house. This could draw in any exhaust gas that is too close to an entry point.

 

 

[G+_Rud Dog]

ove hatlevoll Is there a way to measure air balance so as to not end up with negative pressure?

[G+_Rud Dog]

Robert Hafer Interesting idea solar powered exhaust fans, how did you ensure there was a balance of air, as referenced by ove hatlevoll.

[G+_Rud Dog]

Henry Curley Thank you for the definitions and the fans would replace the gable vents.

[G+_Henry Curley]

You can look up the maximum airflow based on type and size of vent and then size your fan accordingly

[G+_Robert Hafer]

I wasn't really worried about a solar powered fan pulling too much air. There are gable vents on both ends of my house

If I'd thought about it more at the time, I would've added remote sensors/controls. Be nice to know if was still working and in the wintertime it's good to have an attic warmed by the sun.

[G+_Rud Dog]

Robert Hafer sparked an idea. Place IOT in the attic with temp sensor, then thought will it survive the temp in the attic?

[G+_ove hatlevoll]

No you don't not want a warm attic. The heat will melt what ever snow you might have then when it gets to the eave overhang it can freeze causing what is called an ice dam. Any other melt can back up and find any entry points in your roof. Also the snow can act as a blanket keeping your attic temp stable.

[G+_Akira Yamanita]

Rud Dog There's a fantastic YouTube video by a roofing and insulation expert giving a lecture to others in the industry. He's kind of annoying but there's loads of good information. I'll try to find it when I get home.

 

Some items off-hand:

-Fiberglass and blown-in insulation are rated based on no air movement through the insulation. That means unsealed entries into the attic destroy the insulation efficiency.

-Vents that are improperly sized or placed can cause air exchange to happen between the vents themselves (in one, out another) instead of expelling stagnant air from the attic.

-Excessive venting will cause negative pressure, drawing air from your house, and your house will pull in exterior air.

 

Before looking at venting for expelling air, I'd make sure that the intakes (soffit vents) are sufficient for your size roof and climate. Your exhaust shouldn't exceed the intake potential.

[G+_Rud Dog]

ove hatlevoll Don't think it has ever snowed here but good to know.

[G+_Golden Retriever]

Look here images.google.com - Image: VENTILATION — HOMEINSULATORS.COM these spinning roof vents use no energy you have a vent at each eve with wire mesh to keep out birds bats squirrels and other vermints and the stack in the center spins by the hot air rising pulling in cool air from the sides.

 

Old school tech, no energy required, see how smart are ancestors were?

[G+_Akira Yamanita]

Rud Dog I found the video.

 

It's pretty long, but if you can suffer through the lecture, it's well worth watching if you really want to understand the function of an attic and make sure that you don't run into issues.

[G+_Rud Dog]

Akira Yamanita Air tight hole? It was tough to get through but you are right there is a lot of useful information in the video. Thank you.