We hear a lot about the importance of increasing your home’s R-value, but what does it mean? Put simply, R-value refers to the ability of your insulating material to resist the transfer of heat. The higher the R-value, the greater the insulating power. And the less heat you lose, the lower your energy bills.
But increasing your home’s R-value on its own is not enough, because insulation is not the only factor causing heat loss in your home. There are three ways that heat “moves”: conduction, convection and radiation. The R-value relates only to conduction, or the transfer of heat through materials that touch each other, like your walls.
Convection happens as warmer and colder air circulate because of differences in density. As most homes tend to be somewhat “leaky” – the building envelope (siding, sheathing walls) is not air tight – convection can occur.
And radiation is the movement of energy via rays or waves, independent of conduction or convection.
That means increasing your home’s R-value alone will not maximize its energy efficiency. However, it’s still important to make sure your home is insulated effectively.
“A well-insulated house is a bit like dressing for the weather,” says the Canada Mortgage and Housing Corporation on its website.
And since we live in a climate that fluctuates so widely between temperature extremes, “dressing” for that weather is key.
So, how do we increase R-value?
Up your insulation: The most common types of insulation are fiberglass batting, cellulose and foam board. Foam board offers higher R-values, but usually costs more as well. Even better is closed-cell spray foam, which is better than any other type of insulation at reducing air leakage. Although it is a more expensive option, and is best left to a qualified professional.
Not just your walls: A big culprit for heat loss is the attic. Increasing insulation in your unfinished attic can go a long way toward improving your home’s energy efficiency. An easy (and cost-effective) way is to make sure your attic has at least 22 inches of loose fill insulation on your attic floor, or aiming for an R-value of R-30 or R-40.
Your home’s “coat”: It’s also important to do what you can to improve your home’s building envelope. Often, the best time to deal with this is during a renovation, when it’s more likely siding can or is being removed. Improving the envelope can be done in a variety of ways – from things like the house wrap, vapour barrier, types of siding including insulated – and can be done both inside and out, but the best course of action depends on your situation.
If you’re concerned about your home’s R-value and energy efficiency, give us a call!