Configuring Attic Ventilation Based On Outside Temperture

In the summertime the outdoor air temperature as well as the air inside the attic is warmer than it is in the winter and warmer air can hold more moisture than cold air can.

Configuring attic ventilation based on outside temperture.

In these instances systems have a harder time maintaining the desired temperature. Calculations indicate that on a july day in texas a ventilation rate of one air change per minute for a typical attic using 95 degree f air will lower the peak attic temperature to about 101 degrees f. Ideal attic temperatures shouldn t be more than 10 to 20 degrees hotter than outside temperatures. Be it winter or summer the goal is to keep the ventilated attic as close as possible to the outside temperature.

Roof shingle temperatures will be higher during no wind conditions leading to a higher heat load on the attic. Providing half air change per minute will lower the temperature to about 106 degrees f. Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents. If your attic soars above 100 degrees and reaches the 150 mark its time to consult professionals.

So my house burned down a couple of years ago. This design is less efficient when hvac equipment and ductwork is in the attic space. A standard powered exhaust vent turns on when the temperature inside the attic. In the summer time a well ventilated attic helps to keep the attic cooler.

Luckily my wife and i were upstairs and hear the rafters crackling looked outside and saw the wall of fire and got our. Therefore the greatest need for attic ventilation is when there is little wind pressure to force air in and out of the attic. Then stack effect is the prime air mover driven by the attic to outside air temperature difference. But in the winter the amount of water vapor that the air can hold is substantially lower.

Attic temperature depends on the amount of solar radiation construction details and the rate of ventilation. The fire started on an outside wall went up the wall and into the attic space spread across the entire house in the attic with no smoke coming into the house until the ceiling was about to collapse which was far too late. A well ventilated attic helps to avoid problems with moisture and heat buildup.