Air Conditioner Energy Efficiency: Make Attic Insulation Work For You

Attic insulation is there to limit the transfer of heat. Heat energy is active and always trying to move from a hot zone into a cooler zone. During winter, you want to keep that energy from getting out; in summer you want to prevent it from moving in. Heat rises by convection out of living spaces into the colder attic in winter. This causes your furnace to work harder to compensate for the heat loss. During summer, your attic accumulates heat and temperatures may reach 150 degrees. This energy radiates through your ceiling and can raise temperatures in living spaces below as much as 10 degrees. Your air conditioner runs extended “On” cycles to offset the effect, increasing electrical consumption and boosting utility bills.

Heat moving in or out of the attic has other drawbacks. In winter, moist heat entering the attic from living spaces below condenses in the cold air and saturates insulation, generating an environment for mold and warping wood structure. Wooden structural components can be damaged by high summer temperatures, and attic heat may also cause thermal loss from air conditioning ducts routed through the attic. Attic insulation works by limiting conduction and radiation of heat.

It doesn’t do much to stop heat transfer through direct air leaks, however. That’s why a professional attic insulation upgrade always includes identifying and sealing any cracks or gaps that allow air to flow in or out of living spaces. Most residential attics are insulated with fiberglass batts or cellulose loose fill. Attic insulation is rated according to its resistance to heat, or R-value per inch. Fiberglass insulation has an R-value of 3.3 per inch while cellulose is 3.8. In Delaware’s climate zone, the U.S. Department of Energy recommends insulating attics to a minimum of R-38, or approximately 12 inches of fiberglass or 10 inches of cellulose.

For more information about HVAC energy savings, contact the professionals at Sobieski Services, Inc. Our goal is to help educate our customers in Delaware, Pennsylvania, Maryland and New Jersey about energy and home comfort issues (specific to HVAC & plumbing systems).

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