Power vents shouldn t be used because they create more problems than they fix.
Power roof vents problems.
According to the article powered attic fans can create excess moisture structural problems and combustion safety in a home.
This protection feature reduces the amount of air that moves which defeats the purpose of the older designs in the first place.
I used to think roof ventilation was the cure all for everything.
The research concluded that if a powered attic ventilator will be used there must be a good air barrier between the living space and the attic.
One potential problem would be sucking moist moldy air up from the crawl space intothe house.
I blogged about this earlier.
Insufficient ventilation can lead to moisture problems during the winter and decreased energy efficiency during the summer but too much ventilation can be just as bad if not worse.
After that a different level of thinking is required.
Power attic ventilators can cause problems even without air conditioning.
That means you will need to double up your investment in this area.
There is no risk of problems such a rust and bearing wear an tear as well when comparing it to other motorized ventilation alternatives.
Of course you try to make the attic scuttle hole use air tight trim on your ceiling cans but it would be foolish to ignore the benefits of a reasonably powered attic fan working in connection with adequate soffit venting.
Radiant barrier stapled to underside of roof.
Roof vents create an additional roof penetration essentially another place of vulnerability where leaks can occur.
In researching the topic of attic ventilation in the past i figured out the building code rules worked well for roof pitches up to 6 12.
Roof vents and power roof vents are made to work in conjunction with vented soffits so that outside air will replace superheated attic air during hot summer days.
If you use the older style of roof vent to provide air circulation then you must install traps or blockage points that prevent them from nesting in your attic s insulation.
On paper the high vents are.
I would look at a lot of problems and instantly point to insufficient roof ventilation as the cause and recommend more roof.
Another would be backdrafting a water heater and putting carbon monoxide in the house.
Problems and solutions mixed exhaust vents.
For proper ventilation both high and low vents should be installed.