Insulating Your Corpus Christi Home: Why an R-Value Can Vary

A few years ago, the Building Science Corporation conducted a study that measured the insulating R-value of different kinds of insulation. Surprisingly, the study found that R-values aren’t fixed at all, but instead can vary as the temperature rises or falls.

Unfortunately for homeowners in climates like ours, the study revealed that an R-value can actually decline as the temperature rises.

An R-value is the measure of how long insulation can resist temperature change. Each numeric value indicates that it can resist thermal change for one hour. R-13, for example, is supposed to resist temperature change for 13 hours.

The British Science Corporation tested a variety of insulation materials and found that R-13 fiberglass batt insulation had an R-value of 15 at minus 30 degrees, but it declined as the temperature rose. By the time the temperature reached 150 degrees, the R-value had dropped to 11.25.

While our temperatures never reach those extremes outside, it’s possible that your attic does during the summer, when the sun is shining, and it’s hot out. That heat seeps into your home through the ceiling and raises your energy bills. If you have a two-story home, the rooms upstairs could be substantially warmer than the downstairs.

You can do something about the declining insulating R-value by increasing the amount in your attic.   Increasing the amount of fiberglass batts or blown-in insulation in the attic will help to thwart heat gain from the attic, as will insulating products with a radiant barrier. Extra insulation also dampens sounds coming from outside. Insulation is inexpensive and durable. You can do the job yourself or find a qualified contractor to install it.

To learn more about managing a declining insulating R-value in our climate, contact CCAC. We’ve provided outstanding HVAC services to homeowners in the Coastal Bend area for more than 30 years.

Our goal is to help educate our customers in Corpus Christi, Texas about energy and home comfort issues (specific to HVAC systems).  For more information about insulation and other HVAC topics, download our free Home Comfort Resource guide.

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