Power roof ventilators and ridge vents

Reply

  #1  
Old 08-27-11, 09:29 AM
E
Member
Thread Starter
Join Date: Aug 2011
Location: usa
Posts: 9
Received 0 Votes on 0 Posts
Power roof ventilators and ridge vents

I live in southern Oklahoma. We always have hot summers, but this year has been a bummer; anywhere from 60-90 days so far over 100 degrees, and no relief in sight.

My house has 2400+ sq ft (2050 living space plus the garage) under roof. The living space is well-insulated while the garage is not. The garage is partially floored. I have soffits and a ridge vent. There is also a powered roof vent, which I understand is not the best idea used in conjunction with the ridge vent.

This summer, the power vent went out (motor) and I quickly discovered that it had been of more benefit that I had thought. As soon as it gets cool enough to work up there, I plan to replace it. By observation, it appears to be designed for an area of approx 1600-1700 sq ft. I will replace with one at least sufficient for 2400 sq ft.

OK, finally, the question(s). Given this approach, should I try to find a way to block the ridge vent so it doesn’t feed into the power vent without circulating the hot air in the attic?

A second thought would be to replace the power vent with perhaps 3 turbines. In this scenario, would the ridge vent pose the same problem?

I’d appreciate any thoughts.
 
Sponsored Links
  #2  
Old 08-29-11, 02:23 PM
E
Member
Thread Starter
Join Date: Aug 2011
Location: usa
Posts: 9
Received 0 Votes on 0 Posts
Well, looks like the question was too hard or too dumb.
 
  #3  
Old 09-08-11, 11:54 AM
C
Member
Join Date: Aug 2009
Location: USA
Posts: 3
Received 0 Votes on 0 Posts
I have added powered ventilators to 3 different houses. Agree that eventually the motors will need to be replaced, but with 10 year warranties on the motors, that won't be too quickly. In an area with little breeze benefits, any kind of passive ventilation doesn't do a very good job, but the powered ventilators do a pretty good job if placed high enough on the roof. In fact, if the soffit venting is minimal, leaving the passive roof vents open which are installed between half way and 1/3 way down from the ridge will actually help with air movement and reduce temperature.

I've also added un-powered ventilators (chicken coop vents) to 2 different houses, and in a breezy area, they work very well, too. This was in Laramie, where the wind blows almost constantly. Their biggest downfall is that they're pretty ugly!

Ventilators, powered or un-powered, won't remove as much of the hot air if there is a ridge vent, but since heat rises, they'll still do a passable job of lowering the attic temp.

Here in Fort Collins, the amount of breeze that we get is pretty minimal, so the powered vents are a much better choice.

Cary
 
  #4  
Old 09-08-11, 02:00 PM
E
Member
Thread Starter
Join Date: Aug 2011
Location: usa
Posts: 9
Received 0 Votes on 0 Posts
Thanks, I appreciate your thoughts. It's often windy here in Okla, but in midsummer, it can be pretty stifling with no wind.

I think I'll see if there is a reasonable way to block the ridge vents and reinstall one or two power ventilators.
 
  #5  
Old 09-08-11, 02:16 PM
F
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,495
Received 36 Votes on 28 Posts
Properly installed ridge vents with soffit vents work with zero wind. They work because hot air is less dense and rises, exiting the ridge. The cooler, denser air enters the soffit vents creating a continuous venting process. It isn't a fast air change but it is continuous.
 
  #6  
Old 09-08-11, 03:07 PM
E
Member
Thread Starter
Join Date: Aug 2011
Location: usa
Posts: 9
Received 0 Votes on 0 Posts
I chuckle, only because we just went through the worst summer Lawrence went to Arabia. Cool, dense air was nowhere in sight.

J/K. One day in particular, it was about 105 while the temp in my garage was 119. This was because my garage isn't insulated from the ceiling and the temp in the attic was in excess of 130. First, I've got to insulate above the garage and then figure out the ventilation.
 
  #7  
Old 09-08-11, 04:32 PM
F
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,495
Received 36 Votes on 28 Posts
The air heats up in the attic space, this makes it less dense and as it flows upwards and out the ridge vent the outside air WILL enter through the soffit vents. As little as a half-degree of temperature difference will cause this thermal movement. With an attic temperature of 130 and an outside temperature of 105 you have a 25 degree differential. I guarantee that properly installed ridge and soffit vents will allow a huge amount of airflow. You will NEVER get the attic temperature much closer than 10 or 15 degrees above the outside temperature even with huge attic fans.
 
  #8  
Old 09-08-11, 05:26 PM
E
Member
Thread Starter
Join Date: Aug 2011
Location: usa
Posts: 9
Received 0 Votes on 0 Posts
I'm just pulling your leg a little. It's just that this past summer, something was amiss and it was too darn hot to get up there to work on it. In a few days, I will inspect all my soffits and make sure everything is hunky dory.
 
Reply
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: