solar powered attic fan? any experience?

Install cost for your small attic fan was $250 in addition to cost of unit @$500ish = $750 total? Did you also ad exterior intake ventilation, too? Many people install attic vents without providing fresh air intake, severely limiting the attic fan's purpose.

A whole house fan requires one large (three foot square), louvered vent in top floor ceiling plus an equally large amount of fresh air intake ventilation in the attic/roof (that most homes do not have).

$1200 for a fully foam insullated attic AND crawlspace is looking like a real bargain to me. Passive, quiet permanent, maintenance free.

 

This year, I installed two solar gable vents in the attic and one solar gable vent in the garage (which had no roof vents at all). Wow, what a difference it made!

 

And how much did these machines cost you total?

 

$269.99 at Costco
Costco - Solar Power All Purpose Ventilator

I still have to take care of the 30% credit.

 

Plus tax = $300 ish x 3 = $900 + $$$ installation?

$1200 of foam tightly sealed my entire attic and my entire basement crawlspace. Just pointing out money much better spent from a LEED point of view.

 

How does that tightly sealed space cope with moisture from the house? I'm sure there are new techniques, but in the old days we tried to ventilate those spaces to avoid rot and mildew.

Tom

 

$0 installation, except one fan where there wasn't an existing vent and I needed help to install that.

30% credit puts me at about half of your foam install, unless the foam install qualifies for that (or some other) credit as well?

I haven't checked around lately but I'm pretty sure California prices will be much higher than your $1,200. We already have the blown in 'newspaper' insulation in the attic which did a good job keeping our A/C use low in the summer (our highest electric bill this summer was $67, before fan installation).

For the garage that had no venting, would have needed to close in ceiling to install the insulation and that requires permit. It was easier to install the fan. In any event, the garage needed a vent of some sort.

The solution worked for me.

 

Good question and still an important one. The new foams are so tight they are vapor barriers. The proper solution depends on your decision to insulate your ceiling joists vs roof rafters. The r value of one inch of this foam is the same as 5 inches of fiberglass. And there are absolutely no leaks.

 

Self install is never free! I bet you bought your "free" helper dinner! And you had to use a box of Bandaids for a week! Haveing a pro do the work has real value and saves time.

What's with this weird notion that California is tougher and rougher than the rest of the US? prices are exactly the same as Chicago prices (or less). It's priced by the square foot.

$1200 included a local gas company rebate, but we will get the federal tax break too. So the final cost will be less than $1000!!!

$67 A/C bill is incredibly low(the lowest I've EVER heard). You must enjoy having a very warm house or you choose not to use much A/C. If your bill is only $67, what was the point of paying $900 for attic fans and doing that gawd awful attic work yourself?

 

I'm still trying to understand the installation, so please bear with me.

With your foam system, are you spraying the inside of the roof and the rafters? That would make sense from a vapor barrier standpoint. The downside would be the increased surface area, adding to the cost of the insulation and larger surface for heat loss. For example, in our building we have a 12x12 roof pitch, which means the surface area of the roof plus the triangular walls at the end have considerably larger surface area than the joists and ceiling. On the other hand, insulating the rafters would allow this volume to be heated and put to use for something other than storage.

Tom

 

I had an estimate for spray foam insulation in my attic of over $4000.

 

Thanks so much for caring to set everyone straight on what a poor choice they've made regarding attic cooling, whether it be whole house fan, solar fan, old electric fan or whatever.

You are obviously the resident expert on cost and spray foam and what is most efficient for anyone to do, so if I ever decide to do a spray foam project, I'll be sure to let you know so that you can get off my back.

Installing the solar fans was a good choice for me. My house is a comfortable 80 degrees in the summer (I have a long-term illness and find the constant beating of A/C bothersome. Besides, if I'm gardening at 95-100F and accustomed to this temp, then having the house any cooler is too much a shock to my system).

And by the way, it's really none of your business how I choose to spend my money to support the various greening industries, if I choose to spend $25,000 to support solar technology for my $67 electric bill, even though my electric use is minimal, that's my choice and my business. Move on. As I said the first time, this solution worked for me.

By the way, take a look at the install video. It's not hard. Yes I insulated it. No, I didn't need any bandaids. And sure, two friends sharing conversation and dinner after a day of shared accomplishment, Wth is wrong with that?

 

Well said

 

I have two solar attic fans. I do notice my electric bill is a little lower this year, however it's uncertain where I can attribute that to. I'll have to take another look after the summer.

 

Gee I could use something like that on the lower attic over the garage. I have couple Unisolar planels so I wonder if the fan could just had separately.

 

Solutions depend on what you are starting with, local environment, and your budget.

What is the roof constructed off currently ?
Day, night, and humidity in Austin through the cooling months ?

Good roof insulation is a good start, but I suggest not closing off your attic completely; it is a great space to vent heat to at night.

 

I had the roof re-shingled with highly reflective shingles

GAF Roofing - Timberline Cool Shingle - Timberline Cool Series Shingle Shingle Features

I found hybrid solar/thermostatic attic fans, They start turning with any sunlight, but when the day gets too hot, they add house current to keep the attic cool.

GAF Roofing ? MasterFlow Vents - MasterFlow Green Machine Dual Powered

I am hoping this means I do not need to think about my roof for 10 more years. (We added insulation as well)