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icon  Insulation 101


Why insulate your house?

Heating and cooling account for 50 to 70% of the average American home’s energy use. Inadequate insulation and air leakage are leading causes of energy waste in most homes. Insulation, combined with air sealing in your home:

  • Helps maintain uniform temperature throughout your home
  • Keeps heat in during the winter and cool in during the summer
  • Saves you money
  • Lowers your home’s carbon emissions

How does hot and cold air get into my house?

Heat flows naturally from a warmer to a cooler space. In the winter heat moves to wherever there is a difference in temperature. For example, heat will move to the unheated attics, garages, and basements and out of your house. Conversely, during the summer, heat moves from the outside in.


How can insulation help?

By providing an effective resistance to the flow of heat, insulation in your ceilings, walls, and floors decreases the heating or cooling your home needs


Insulation basics

There are several common types of insulation: cellulose, rigid foam board, fiberglass (in both batt and blown forms), and spray foam. Reflective insulation (or a radiant barrier) is another insulating product which can help save energy in hot, sunny climates.

Insulation performance is measured by R-value - its ability to resist heat flow. Higher R-values mean more insulating power. Different R-values are recommended depending on where you live for walls, attics, basements and crawlspaces. Insulation works best when air is not moving through or around it.

Sealing air leaks before installing insulation to ensure that you get the insulation’s best performance.


Does my home need more insulation?

To get the most savings, add insulation to your attic.

To see if you need more insulation, look across your uncovered attic floor and if your insulation is level with or below the attic floor joists, you need to add more insulation. The recommended insulation level for most attics in Maryland is R-49 (or about 15-20 inches, depending on the insulation type).  


Source: Department of Energy – Insulation fact sheet


More insulation topics:

Types of insulation
Installing insulation

R-value: Used to measure how well a material resists heat flow. A high R-value means the insulation is keeping heat in your home in cold seasons, and heat out in warm seasons.
Air sealing: Combined with proper insulation, air sealing plugs holes or cracks that let air into your home. These leaks are common around doors, windows and attics. Sealing can be accomplished with caulk or weatherstripping.
Insulation: Materials used to keep air from the home inside and keep outside air out and greatly reduces heating and cooling bills.
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