While the value of insulation is frequently associated with winter, in summer, insulation can be just as critical to optimum indoor comfort and energy-efficient operation. Insulation is a material that inhibits the movement of heat—no matter which way it’s moving. In winter, insulation helps keep heat from escaping the house to the colder zone outside. During summer, insulation resists the flow of heat into the house. This maximizes air conditioner efficiency, lowering cooling costs and reducing wear and tear on the A/C.
Heat in Motion
On a hot summer day, solar energy heating the roof raises temperatures in the enclosed attic as high as 140 degrees. This captured heat energy continuously radiates downward through the ceiling into the home’s living spaces, raising temperatures in rooms below by as much as 10 degrees. Attic insulation installed between the joists in the attic floor is the primary location to inhibit attic heat infiltration in summer.
How Much Do I Need?
The Environmental Protection Agency recommends an insulation R-factor of at least 38 to resist heat transfer from the attic. Two types of insulation are most common in attics:
- Fiberglass batts are those rolled blankets of pre-cut insulation that look like pink cotton candy. To reach the minimum R-factor of 38, depth of fiberglass batts in the attic should be at least 12 inches.
- Cellulose loose-fill is blown into the attic under air pressure. Consisting of pulverized paper and cloth, it looks like a layer of new-fallen snow when in place between the attic joists. To achieve the EPA recommended R-factor, depth of cellulose insulation should be a minimum of 10 inches.
- To achieve optimum results, generally speaking, you should exceed the EPA minimum depth requirement. When adding new insulation to increase depth, the existing fiberglass batts or loose-fill insulation need not be removed. The new layer can simply be added atop the existing layer to constitute the new total depth.
For more about the value of summer insulation, ask the experts at Aggressive Mechanical.