Anyone every install their own attic fan?

Scott R · Scott R's Garage

I want one, I have a pre-wired blank plate exactly below where I would think an attic fan should go. How hard of a job is this? Anyone done it?

onewhippedpuppy · 06-13-2009, 10:19 AM

No real big deal. Cut hole with circular saw or sawzall, leaving plenty of extra shingle to trim later. Install fan in hole, flash, trim shingles and seal/nail down. I need to put one in, but my roof is 40 ft high and steep. Yeah, I'm a big sissy when it comes to heights.

rick-l · 06-13-2009, 10:19 AM

Don't cut a roof truss like the PO in my house did.

rick-l · 06-13-2009, 10:21 AM

Are we talking whole house fan that vents to the attic or a fan to aid the gable and ridge vents?

Scott R · Scott R's Garage

I'm looking for a ceiling mounted fan that's flush with the ceiling and draws into the attic. The way I see this project is, get the fan, cut the ceiling, and then wire it up?

Zeke · 06-13-2009, 11:37 AM

That's a whole house fan. Most will require cutting at least one ceiling joist and heading off at each side. It can be wired to a switch, timer, timer switch or t-stat switch. Be sure to wire in a cut off switch for safety.

rick-l · 06-13-2009, 02:23 PM

Quote:

Originally Posted by milt

Most will require cutting at least one ceiling joist and heading off at each side.

If it is a pre-made roof truss, common in the midwest, the bottom member of those things are under tension.

If I were doing it and it required more than the rafter spacing (24"??) I would build a box and mount it on top of that.

On mine it looks like the guy wanted it centered in the hallway, cut the truss and put some 2x's in like a header. Looks like they pulled out 1/2 inch.

Zeke · 06-13-2009, 02:38 PM

Yeah, I'd not cut a truss. But, there should be a bearing wall near the hallway where most of these things are installed. The other way to look at how forces affect a truss is to think of them holding the roof up and not always just holding the ceiling span. Still, the bottom chord is in tension, as you say, and must be tied.

Scott R · Scott R's Garage

basically, not knowing what a "truss" is I'm already in over my head

gr8fl4porsche · gr8fl4porsche's Garage

You indeed may be, but there is an alternative.

There are whole house fans which fit inside of the trusses and use multiple smaller fans rather than a large one. They have insulated mechanical lids which open and close when you hit the switch.

Joeaksa · 06-13-2009, 03:16 PM

Its easy and a very good mod to the house. Bought it at Home Depot with a discount and a friend of mine and I installed it in a morning. Biggest hassle was finding 110v AC in the attic (it had 220vAC for the A/C) and sweeping up the insulation that fell out of the hole.

I put it in 4-5 years on and it runs all the time when the temps are under 100 over here. Its on right now, when I would otherwise have the A/C turned on as its in the 90's over here.

porsche4life · porsche4life's Garage

There was an "Ask This Old House" That covered exactly this. Can't find it on their site tho.

Scott R · Scott R's Garage

Quote:

Originally Posted by Joeaksa

Its easy and a very good mod to the house. Bought it at Home Depot with a discount and a friend of mine and I installed it in a morning. Biggest hassle was finding 110v AC in the attic (it had 220vAC for the A/C) and sweeping up the insulation that fell out of the hole.

I put it in 4-5 years on and it runs all the time when the temps are under 100 over here. Its on right now, when I would otherwise have the A/C turned on as its in the 90's over here.

That's the easy part for me, the builder left me 110V wiring in the exact spot you would put the fan.

Hugh R · 06-13-2009, 04:37 PM

Get a variable speed one, not the three speed one. If it's near your bedroom door, run romex, or metal flex to another location away from your bedroom door. Put it near the kids room. They work well, I used to have one in my old house. Make sure a window is open, or you'll pull the ashes out of the fireplace as it tries to pull air into the house.

Joeaksa · 06-13-2009, 04:45 PM

Scott,

Hugh is spot on. Mine is a two speed and there are times I would love to have a three speed but thats life.

Another thing to look at is to install a timer switch on the fan, so that you can turn it on and have it run while you are sleeping, yet turn off in the middle of the night when not needed.

Joe

Scott R · Scott R's Garage

Quote:

Originally Posted by Hugh R

Get a variable speed one, not the three speed one. If it's near your bedroom door, run romex, or metal flex to another location away from your bedroom door. Put it near the kids room. They work well, I used to have one in my old house. Make sure a window is open, or you'll pull the ashes out of the fireplace as it tries to pull air into the house.

I don't have any kids yet, but I'm trying.

Joeaksa · 06-13-2009, 05:18 PM

It does cover up the "moaning sounds" very well...

VINMAN · 06-13-2009, 05:23 PM

If you install one make sure you have adequate venting out of the attic. Gable end , or roof vents. Ive seen installations where the CFMs on the fan was way to high for the attic vents.

Scott R · Scott R's Garage

Quote:

Originally Posted by VINMAN

If you install one make sure you have adequate venting out of the attic. Gable end , or roof vents. Ive seen installations where the CFMs on the fan was way to high for the attic vents.

I bet I don't, my soffets are vented, that's about it.

notmytarga · notmytarga's Garage

I have installed one of these:

http://www.wholehousefan.com/PRODUCTS/HV1600-GR.html

In two houses now. They make more sense than a high flow fan that is poorly insulated (you cover the attic side in the winter ideally) and cools the house immediately with air exchange. Once you shut the big ones off because they are so high flow the CONTENTS of your house heat the air back up.

The fan systems on the site above use little power - lower flow - and can run as long as you want - which cools off the entire contents (furniture, floors, walls etc) of the house by morning.

They fit is smaller framing too. I would have gotten a bigger one that has the fan further into the attic if I know I needed a bigger unit to match the performance in my smaller house.