Attic
The attic of a home is typically unconditioned space, meaning that it is not heated or cooled with the rest of the house. For that reason, the attic needs to be well-sealed from the rest of the home with sufficient insulation, and kept as temperate as possible using proper ventilation and radiant heat barriers.
Attic Insulation
One of the most important things that a home owner can do to reduce heating and cooling costs is to ensure that unconditioned air does not infiltrate the house or venting system, or pull conditioned air into the attic from the house. This is done using insulation.
Insulation is measured in terms of R-value. Different types of insulation have different R-values, and the total R-value is measured by taking the thickness in inches of your insulation and multiplying by the R-value per inch of your insulation type.
Texas state building code requires a minimum R-value of R-32 in an attic. Current Energy recommends using R-38 for maximum comfort and effect.
Find the Department of Energy (DOE) recommended R-value for your region here.
Radiant Barrier
Attic temperatures in the summer months can exceed 150 degrees Fahrenheit. Some of this heat develops when the sun's radiant energy penetrates your roof and builds up heat in your attic. Shingles, insulation and conventional roof sheathing do create a barrier against hot air moving into the house, but they do not have any defense against the sun's radiant energy. For this you need a reflective barrier, on your roof or in your attic (or both) to protect against this intense heat transfer. Installation of a radiant barrier in the attic can lower temperatures significantly, thereby allowing your air conditioner to work more efficiently and effectively.
Ventilation
Proper ventilation is also an important part of keeping your attic comfortable. As air heats the attic during the hotter months, it gets less dense. Air can then be vented up and out through an attic fan while cooler air from outside can be drawn in through lower inlets. Not only does this keep the attic cooler (very effective when used in conjunction with a radiant barrier), it helps to prevent excess moisture from settling into the attic and causing water damage and mold growth.
Solar powered attic fans are an effective tool in helping this process. These fans have a temperature gauge that sets them to run when attic temperatures hit a certain point. The solar panel at the top powers the fan and requires no additional wiring.
