Yep. If your basement is used as living space (family room, rec room, extra bedroom, kids playroom, whatever) and is heated, then it needs to be properly insulated like the rest of your home. The cement or concrete block walls do not offer enough insulation value. If your contractor tells you the cement alone is sufficient, get a new contractor!
The R value of concrete blocks is only about 1, or maybe 2 to 3 if the cores are properly filled. Cement walls offer an R value of 1 per inch…so an 8 inch wall would offer R8. Neither is sufficient. Even though the outside of the wall may be earth, the warm air in the basement will still want to travel to the cooler temperature of the basement walls and the cooler earth on the other side (keep in mind the temperature of the Earth is approximately 55 degrees).
Basement walls should be insulated to at least R19. This can be accomplished with fiberglass insulation, or you could use foam board. Always leave a slight space between the concrete/cement walls and the insulation, since the walls will be moist due to the concrete/cement, and moisture condensing on them. The space will prevent the foam or fiberglass from becoming wet, and will help prevent mold.
Did you know that the cement slab should be insulated as well? It should be, for exactly the same reasons that we insulate the walls – to prevent warm air from being absorbed by the cooler cement slab. The best time to insulate the slab is when it is poured, as the home is being built. If you are having a house built now, talk to your builder about this, and make it a priority.
But what about existing slabs? Well, our options are pretty limited. Carpet will help as an insulator, but is generally not a good idea in basements due to moisture. A felt pad under laminate flooring will help, and the laminate flooring will add about an R .5. If you plan to go ceramic tile, you could build a sub floor first, and install rigid foam boards.
The key to treat your basement area like any other room if you plan to use it as heated space….even if it is surrounded by earth on most sides. It needs to be well insulated to slow the heat from transferring through your walls and floors.
If you are curious how much heat your basement will need, and how much you could save by insulating it, please see my website at www.saveenergyusa.com for more information on how to save energy….AND help the earth.
Think energy savings every day!
Energy Saving Tip of the Week: If you have separate heating zones for the living room area and the bedrooms, then close the doors to the bedrooms when you are in the living areas (living room, family room, kitchen area, etc.) and do not plan to use the bedrooms for any length of time (and vice versa when you go to bed). Otherwise, your heat from the living area is trying to heat the unused bedrooms too, causing you to burn more fuel, and spew more C02 into the atmosphere and harm the earth. Save that energy, and save that money, and help the earth!
