Roof power vents

[Homerboy]

Full disclosure:
I own a 70 year old, 2 story brick cape code in south eastern, WI.
The attic insulation is admittedly old, and needs to be replaced (time and money I do not currently have).
Most the windows on the house are original (single pane with 1970s storms)

In the summer, the 2nd story (bedrooms) simply do-not get the cooling they need. It's hot up there.

When we moved in, there was a power vent and the 2nd story seemed to be cooler. Admittedly, we have put an addition on since we moved in.

For the past couple of summers, that power vent has been broken -- first the motor died and last summer, the dome on it actually ripped off during a storm leaving a 15" diameter hole in my roof all night while it poured!

I was planning on replacing the power vent but have been doing some reading saying that they really don't work -- at least from a $ saving standpoint since they end up replacing the hot attic air with conditioned air from the house.

While I would love to save money, my initial hope is just to cool those bedrooms down. Will a power vent help with that?

Bonus question: what's the verdict on solar powered units? I'd rather not pay to have an electrician run the install (I can not do this myself for various reasons) and I figure the solar may save a few of the pennies I'm costing myself if these things do, in fact just suck your conditioned air out of the house.

Something like:
http://www.amazon.com/Broan-355BR-M...=1432667989&sr=8-11&keywords=power+roof+vents

Versus:
http://www.amazon.com/dp/B00E382RJM...TF8&colid=3LJ2LRW5I1IMO&coliid=I3FSN7JWTU0SK7

Thanks in advance.

 

[cbrsurfr]

Power vent should be sucking in air from the eaves not inside your house. Skip solar if you already have power run to it. Wiring in a new one should be easy.

 

[highland145]

My .02... I think you'd get better results with insulation. R 13 15"X32' $11.00 R 19 15"X39' $26.50. You just roll it out if the attic isn't too painful to get in.

70 + yo house for me too. I have a gable fan and the room below it stayed several degrees hotter that the rest of the house. There are a few inches of rock wool and a layer of R 13. I added R 19 and the problem was solved. Went ahead and did the rest of the attic, one section at at time.

I do believe the fan helps but the more things you can do, the better.

Edit: Yeah, it's a lot more $$ but you'll never have to do it again.

 

[shabby]

My .02... I think you'd get better results with insulation. R 13 15"X32' $11.00 R 19 15"X39' $26.50. You just roll it out if the attic isn't too painful to get in.

Fiberglass is junk, go with cellulose.

 

[highland145]

Fiberglass is junk, go with cellulose.

Got a link?

 

[shabby]

https://www.youtube.com/watch?v=b5LbVDl7brI
https://www.youtube.com/watch?v=_AzxowD6if0
https://www.youtube.com/watch?v=xdSBRPnFvlM
https://www.youtube.com/watch?v=yA2sVm3Fewo

 

[highland145]

https://www.youtube.com/watch?v=b5LbVDl7brI
https://www.youtube.com/watch?v=_AzxowD6if0
https://www.youtube.com/watch?v=xdSBRPnFvlM
https://www.youtube.com/watch?v=yA2sVm3Fewo

BS. Sealed bird house with no vent? You hate birds?


Actually, I thought that was cool (heh) except for the professional installation cost and I wonder what the power vent will do to help reduce the heat transfer. 95 degrees being pulled into the attic space by the vent...

I know I've had good results with the extra insulation and the vent as far as the inside temp goes.

At the end of the day, wonder what the savings could be. Vent, no vent, fiberglass, cellulose, etc. Could it take you 15 years to justify the cellulose? With no vent? I'm sure there's a study because there's $$ to be made/saved.

Thermal paint, FTW... right?

 

[Greenman]

It's very possible that your vent is sucking air out of the house, old houses leak a lot. But I don't see a single attic vent making a substantial difference inside the house, unless there is no attic insulation.

The place to start is attic insulation, use blown in as it isn't subject to air movement from an imperfect instillation. Depending on existing conditions, an attic fan may be of real value.

 

[RagingBITCH]

Insulation FTW first.

With regards to whirlybirds vs powered fans vs solar fans vs ridge vents vs foam insulating walls/roof - I did reading on all of those when I had insulation put in my old house. There's "experts" that recommend each one and knock all the others. In reality, your home comfort will benefit more from sealing up gaps b/t your interior walls and attic/exterior. How the air circulates through the attic is just a smaller piece of the puzzle.

 

[TheSlamma]

Power vents put negative pressure on your attic, in all houses especially older houses this will pull the air from the house up and in. Avoid these things in every situation, when the motors seize up they can also become fire hazards.

Ridge vent + eaves vents is the best possible combo IMO. Followed by whirlybirds/turtles.

As others have stated you need to add insulation. 70 year old house might have mineral wool up there. That stuff stays good for eternity you can just add to that if you want or go with other blown in options on top of it.

My personal pref is always mineral wool though. It's better in almost every way compared to foam, cellulose and fiberglass when it comes to fire, insects, rodents and mold.

 

[echo4747]

Power vents put negative pressure on your attic, in all houses especially older houses this will pull the air from the house up and in. Avoid these things in every situation, when the motors seize up they can also become fire hazards.

Ridge vent + eaves vents is the best possible combo IMO. Followed by whirlybirds/turtles.

As others have stated you need to add insulation. 70 year old house might have mineral wool up there. That stuff stays good for eternity you can just add to that if you want or go with other blown in options on top of it.

My personal pref is always mineral wool though. It's better in almost every way compared to foam, cellulose and fiberglass when it comes to fire, insects, rodents and mold.

All good advice here ... ridge vent and soffit vents + more insulation. I see you say the home is in Wi the insulation will also help reduce your heating bills in winter too

 

[inachu]

Heck I remember as a little boy my grandparents home would be hot in the summer and they just turn on the attic vent and within 2 hours the house would really be cooler.

I would say it is worth it 100%

 

[spacejamz]

Heck I remember as a little boy my grandparents home would be hot in the summer and they just turn on the attic vent and within 2 hours the house would really be cooler.

I would say it is worth it 100%

That is whole point of properly working roof/attic ventilation so that you don't have to flip a switch...

If your ridge vents or whirlys are working properly, the heat should automatically flow out of the roof and be replaced with the cooler air from the soffets and should not collect within the attic space....

 

[pmark]

Fiberglass is junk, go with cellulose.

So blown-in Cellulose is better to go with than Fiberglass? Is one better at preventing (or more like discouraging) rodents?

Cellulose is a little more expense per sq ft and you need to get twice as many bags if you want the free machine rental from home depot (may or may not matter).

 

[NutBucket]

No, rodents love either. Just fix the damned holes!

 

[highland145]

That is whole point of properly working roof/attic ventilation so that you don't have to flip a switch...

Wonder if he means a whole house fan?

We had one growing up.

 

[JEDI]

Full disclosure:
I own a 70 year old, 2 story brick cape code in south eastern, WI.
The attic insulation is admittedly old, and needs to be replaced (time and money I do not currently have).
Most the windows on the house are original (single pane with 1970s storms)

In the summer, the 2nd story (bedrooms) simply do-not get the cooling they need. It's hot up there.

When we moved in, there was a power vent and the 2nd story seemed to be cooler. Admittedly, we have put an addition on since we moved in.

For the past couple of summers, that power vent has been broken -- first the motor died and last summer, the dome on it actually ripped off during a storm leaving a 15" diameter hole in my roof all night while it poured!

I was planning on replacing the power vent but have been doing some reading saying that they really don't work -- at least from a $ saving standpoint since they end up replacing the hot attic air with conditioned air from the house.

While I would love to save money, my initial hope is just to cool those bedrooms down. Will a power vent help with that?

Bonus question: what's the verdict on solar powered units? I'd rather not pay to have an electrician run the install (I can not do this myself for various reasons) and I figure the solar may save a few of the pennies I'm costing myself if these things do, in fact just suck your conditioned air out of the house.

Something like:
http://www.amazon.com/Broan-355BR-M...=1432667989&sr=8-11&keywords=power+roof+vents

Versus:
http://www.amazon.com/dp/B00E382RJM...TF8&colid=3LJ2LRW5I1IMO&coliid=I3FSN7JWTU0SK7

Thanks in advance.

i asked that same question about solar:
http://forums.anandtech.com/showthread.php?t=2427615&highlight=solar

and don't get a whole house fan.
just get a roof fan that pulls in outside air thru the sofits

 

[pmark]

No, rodents love either. Just fix the damned holes!

I guess that would mean finding the holes first