Mills Efficient Home

Increasing attic insulation is the most effective way to increase the energy efficiency of your home. Attic insulation eases the strain on your heating and cooling system; thereby reducing energy costs and improving comfort.

Attic insulation makes it much easier for your heating and air conditioning system to keep your home cool in the summer and warm in the winter.  Attic insulation does this by trapping inert air and creating a temperature-neutral pocket between areas of opposing temperature. This trapped pocket of air doesn’t allow heat to transfer from the warmer area to the cooler area so that, in the summer, the air cooled by your AC unit stays colder longer. All this adds up to running your air conditioner less and less – extending its life and using less energy, saving you even more money.

The most common types of home insulation are blown fiberglass, blown cellulose, fiberglass batt or fiberglass blanket. Blown fiberglass insulation is the best type of attic insulation, providing the highest level of energy efficiency as well as a bevy of other benefits.  Blown fiberglass is not dusty so it won’t hurt your eyes or lungs. It’s naturally flame retardant so it greatly reduces the risk of attic fire.  It has low chemical content so it won’t damage your sheetrock or joists, and it never settles, maintaining a consistent, high R-value for as long as it’s in your attic.

R-value is a measurement of the effectiveness of home insulation. The higher the R-value, the less heat will pass through your attic insulation. To illustrate how insulation reduces cost, imagine  the temperature in your attic is 140 degrees. But you’re running the air conditioning to keep the inside temperature at 75 degrees.  An average home has 3 to 4 inches of old insulation, with an R-value of 6. That level of insulation allows 5200 btu to come through your ceiling every hour. An average, 2000 sq ft home with an normal air conditioning system (3.5 ton, SEER 11) can generate around 48,000 btu/hour. This means your AC must work 11% harder every hour just to keep your home at constant temperature, let alone actually lower the temperature. When your poorly-insulated attic is fighting against your AC all summer, that 11% will cost you thousands and thousands of dollars in just a few years.

With an R-value of around 2.5 per inch, a proper amount of blown fiberglass insulation drastically reduces heat transfer and your AC unit can easily keep a constant, comfortable temperature. The Department of Energy’s  recommended level of attic insulation for most regions in the US is an R-value between R38 and R60, which is between 15 and 22 inches of blown fiberglass insulation.