Insulation Facts

How much do you know about home insulation and saving energy at home? Learn the truth about some common misperceptions about insulation.

Common Belief:

Attic ventilation is not needed when a proper vapor retarder is used on the attic floor.*

The Facts:

Even with a good vapor retarder, proper ventilation is essential to prevent damaging condensation. Eave vent openings at the roof overhang combined with a ridge vent, roof vent, or gable vents, are effective ways to create a positive movement of air in and out of the attic.

*Note: Check your local building codes on ventilation and moisture control requirements in your area.

Common Belief:

R-value refers to the thickness of the insulation.

The Facts:

R-value refers to insulation’s resistance to heat flow, not to its thickness. Tiny air pockets trapped in the insulating material resist the passage of heat – heat gain in the warm summer months, and heat loss in the colder months. The higher the insulation’s R-value, the greater its insulating power.

Common Belief:

Compressing Insulation into a smaller space will increase its R-value.

The Facts:

Fiberglass insulation works on the principle of trapped air pockets. By compressing fiberglass insulation, you decrease the amount of air trapped in the material, therefore reducing the overall R-value. So compressing a thick product into a small space won’t necessarily give you a better R-value.

Common Belief:

Insulating the ceiling will just force more heat to leak out of the windows.

The Facts:

Adding insulation to one part of a home won’t increase the “pressure” on heat losses through other parts. However, poorly insulated areas will continue to be major sources of heat/cooling loss. Reduce heating and cooling costs by ensuring that each area of your home is insulated to the R-values recommended by the U.S. Department of Energy.

Common Belief:

Installing foam gaskets in electrical outlets will significantly reduce air leakage.

The Facts:

Measurements have shown that less than 2%** of a home’s air leakage is due to outlets.

**Sources of Air Leaks in Your Home, 2006 edition of the U.S. DOE Energy Savers booklet.

Common Belief:

Turning up (down) the thermostat will make your home get warm (cool) faster.

The Facts:

It’s tempting to think of a thermostat like a water tap. The wider you open it (the higher or lower you set the temperature), the more hot or cold air will come out. In reality, it works more like a light switch. If it’s on, the same amount of light (hot or cold air) will come out no matter what the temperature.