No attic ventillation?

kcrossley2

I just purchased a new home and I noticed that there doesn't appear to be any rooftop ventilation—no gable vents, no ridge vents, and definitely no power vents. There are soffits though. I checked the attic and the house is designed to accommodate a ridge vent system. The only explanation I can come up with is the builder was worried about aesthetics.

Is this normal for new construction? Are there any county codes that specify a certain amount of attic ventilation? If I have to put in some attic ventilation on my own, is it better to go with ridge vents or a fan?

Ed the Roofer

If you have a continuous length of ridge on your home and it is a gable style instead of a hip style, a full length continuous ridge vent would be preferable.

Research has shown that PAV's, (Powered Attic Ventilators), consume more energy than they save by reducing the attic temperature. Additionally, the PAV's will "suck" out the climatically cooled air conditioned air from the living quartrs of the home, especially if there are insufficient soffit fresh air intake vents installed.

Also, for a PAV to be functional, you must choose one that works year round, based on a thermostat and a humidistat, to not only relieve the heat build up, but the humidity content as well.

For any proper exhaust ventilation system to function properly, a fully functioning soffit fresh air intake ventilation system must be in place on your home.

Ed

kcrossley2

So there's really no cooling benefit or energy savings to installing a PAV?

Ed the Roofer

That is correct.

The cooling effect that one feels is due to the A/C having to run more continuously since the internally controlled climate is being sucked up into the attic environment and then being expelled through the attic fan.

This probably also has to do with the fact that nearly every single home, (95% per manufacturer studies), do not have anywhere near the proper amount of fresh air intake vents. By the intake ventilation being limited and by the PAV being introduced, the air has to be getting pulled from somewhere.

Therefor, the cost of the additional A/C to replenish the homes interior living environment plus the cost of continuously running the PAV has been shown to be self defeating when it comes to cost and energy conservation.

Ed

redline

Did you have this home built or did you buy it from a builder?

kcrossley2

I had it built.

Ed, there are conflicting reports on PAVs. I agree that if the house does not have well built soffits the scenario you played out will likely occur. However, there are also reports that if the PAV is used in conjunction with adequately built soffits it can effectively help lower your attic temperature by increasing airflow from the soffits and making it easier to cool the home, which ultimately lowers energy costs.

Ed the Roofer

That is what I stated before, but the key is that the home must have the proper amount of fresh air intake ventilation, which up to 95 % do not.

Ed

kcrossley2

But how would one know?

elementx440

what about this? it popped up for "ads by goooooogle"

so much for aesthtics
http://www.skylightguys.com

__________________
Hain't we got all the fools on our side?
And ain't that a big enough majority in any town?
-Mark Twain

Ed the Roofer

You must take the time to calculate the total NFVA of the intake and the exhaust ventilation products.

The intake should be at least 50 % and up to 60 % of the total ventilation formula to meet the "minimum" requirements.

Every ventilation product has a rated NFVA per square foot or per lineal foot when installed per the manufacturers specifications.

Ed