Insulation R-Values: What You Should Know for a More Efficient Home

In making your Coastal Bend home more energy efficient, you may have heard that increasing insulation R-values in your attic can shave your energy bill. If you do not know what R-values are, however, you are at the mercy of the insulation sales person at a home improvement store. That can lead to disappointment by a low return on investment if you overspend on too much insulation.

The Science of Insulation

Just about any material is one of three things: a heat insulator, conductor, or semiconductor. Heat transfers from hotter to cooler objects or regions and does so most easily through a conductor. When a material resists heat transfer, it insulates. A semiconductor behaves as both a conductor and insulator.

Resistance-value (R-value) is a measure of a material’s resistance to thermal energy transfer. Everything has an R-value. Air, for example, is an inexpensive insulator, at R-1 for around three inches of open airspace, which is the same R-value as an inch of hardwood.

Building Material R-Values

The secret to improving insulation R-values is to select insulation materials that truly reduce your Coastal Bend home’s heat transfer. During Corpus Christi’s summers with temperatures routinely in the 90s, insulation keeps expensively cooled air inside the occupied home and keeps hot air out.

Insulation types usually available in the Corpus Christi area include flexible, rolled fiberglass batting (faced and unfaced—with paper and without), blown-in cellulose, fiberglass, and rigid foam board. Expanding spray foam, professionally applied, is another choice.

What to Add

• If your Coastal Bend home already has three to four inches of attic insulation, add R-25 to R-38 unfaced batts on top to bring insulation R-values up to around R-60. Unroll them at right angles to the joists.
• If your home has no attic insulation, add R-30 to R-60. You will see your summer energy bill drop noticeably, because the hot air in the attic will not transfer into the air conditioned space below.

For more help understanding how insulation R-values can save you money on your Coastal Bend home’s fuel bills, contact us at CCAC, Inc.

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 R-values and other HVAC topics, download our free Home Comfort Resource guide.

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