One of the ways a house loses and gains heat is through conduction. Conduction is the movement of heat through solid objects, such as walls, the ground, floors and ceilings. Heat always moves toward the cold, trying to equalize the temperatures, and does move through solid material. Heat inside a warm house will always try to escape, and in the summer the heat outside tries to get in.

Insulation in floors, ceilings and walls is helpful because it traps tiny pockets of air, which retard the transfer of heat. Insulation won't stop heat entirely, but it will slow it down.

Insulation's effectiveness is tested by it's "R value," which is its ability to resist the heat flow from warmer to cooler areas. The higher the R value, the more effective the insulation. It is important to remember that a material's insulating ability is based on R value not thickness.

Types of Insulation 

Batts & blankets, Fiberglass. The R value per inch is 3.1 to 3.5. It is best suited for standard joists, studs or rafter spacing in attics, walls and the underside of floors.

Loose Fill Cellulose, fiberglass, vermiculite. The R value per inch is 2.2 to 3.7. It is best suited for non standard spacing, infill of block walls and when spacing between joists has many obstructions.

Rigid board Polystyrene, polyisocy­anurate, urethane, bead board. The R value per inch is 3.5 to 5.5. It is best suited for basement walls, foundations, exterior walls, interior walls and cathedral ceilings.

Polyurethane Foams. Open-cell SPF has an R-value around 3.5 per inch and typically uses water as the blowing agent.  Closed-cell SPF has an R-value of around 6.0 per inch (aged R-value) and uses high R-value blowing agents.

Where to add insulation to a home

1. Ceilings below an unheated attic.

2. Floors above unheated basements, crawl spaces, garages and open porches.

3. Uninsulated exterior frame walls.

4. Between sloping rafters. Be sure to leave an air space for ventilation between the insulation and the roof. (Select insulation accordingly.)

5. In the back of band or header joists around the perimeter of the basement.

6. Basement walls when below grade space is finished for living purposes or when the basement doesn't enclose a fossil fueled furnace or boiler (gas/oil).

7. Basement walls where the above grade exposure exceeds 50% of the interior wall surface.

When adding insulation in the attic, be sure to keep at least 1" space between the insulation and the sheathing so air from the soffit/eave vents can flow to the ridge and/or gable vents.