Quote:
Originally Posted by the dufferz  While the temperature is less than you have in the winter, comparing indoor to outdoor comparison, If you go into your attic on a day when it is 95 degrees, the attic very well can exceed 160 degrees. That's a 90 degree difference between that and a 70 degree interior temp, so it like having a winter time low of -20.
Sorry for the less than encouraging news. |
Attic ventilation should be improved if the attic temperature is more than about 20 F higher than the outside air temperature. Such high temperatures as that (160 F!) will substantially shorten the life of asphalt roofing and plywood roof sheathing.
Homes built before modern building codes mandated adequate attic ventilation can benefit. It is relatively easy to accomplish in a variety of ways. Convective cooling using ridge vents, added soffett vents, even a cupola or wind turbine vent will in nearly all cases keep the attic temperature no more than 20 F above the outside air temp. In particularly difficult cases, thermostated, powered exhaust fan vents may be needed. The effort is quickly recouped in lower air conditioning costs.