Re: Solar Screens
"LF, make sure your attic has plenty of airflow also. We just bought our house a few months ago and with the recent 100+ temps, the AC was not keeping up. I checked the attic and had no way for the heat to go out, just the eve vents, but heat rises..................so they weren't helping. I installed a power attic fan, and what a difference it made. The AC actually keeps up!!! You got me wondering about adding the solar screens now too!!"
Glad you sorted out one of the most common problems with homes and heat buildup...the attic. It's a common belief that 'heat rises' , actually heat doesn't rise, heated air rises. Heat can travel in any direction. If you were to place a heat source in the center of a large boulder, would the heat only heat the top of the stone? Nope, the heat would migrate in all directions, including down to heat the boulder evenly, from the inside out. Heat tends to migrate from a medium of more heat to a medium of less heat . In a home ceiling, the attic is warmer, the room below is cooler. Heat will migrate downward through the insulation and drywall and heat the room air below. The reason for the insulation is to slow this migration, air is a good insulator, if it isn't moving. In colder climates, when the room is warmer, heat will move up through the drywall and insulation into the attic.
All of this heat energy stuff applies to the vertical walls too. The key to the speed at which this heat is transferred is determined by the temperature differential between the two areas and the insulation that tends to slow the transfer. You can slow this transfer , but you can't stop it. The heat transfer will continue until both sides are at the same temperature. When both sides are equal, the heat transfer will stop.
In a normal hot attic, cooler air in drawn up into the attic through the eve vents. Heated air in the attic should be allowed to leave the attic through roof vents or continuous ridge venting. This updraft carries the heated air (and moisture ) out of the attic, keeping the ambient attic air temperature closer to actual outside temps. Attic temps can reach 180 degrees, that's one heck of a heat source to fight. By venting the attic, and allowing the heated air to rise ,cooler air is drawn in through the eves. Since the attic is cooler, there's less of a temperature differential between the attic and the rooms below, and less heat migrates downward. The homes A/C won't have to work as hard to maintain a cooler temperature.
Multi pane windows filled with inert gasses work well too. The addition of a simple awning to stop the sun from hitting the glass in the first place will keep the glass surfaces much cooler.
