They say the human body loses most of its heat through the head. So when it’s cold out, you put a hat on. Before winter approaches (or even autumn!), invest in a hat for your house.
According to Austin Craig, sales consultant for Davenport Insulation, attic insulation is critical to maintaining a constant temperature in your home without wasting energy. “Attic insulation is the first and foremost concern,” he says, and should be addressed before windows and walls.
As colder temperatures creep in this fall and winter, here’s what you need to know to make sure your house has the best hat for its head.
Checking the temp
It’s not easy figuring out whether you need new or upgraded insulation, but the best place to start is your attic.
Craig says to try to find out what similar homes in your area cost to heat. If your bill is excessively high, you likely have an attic insulation problem. If you have a second floor where the temperature is more than a few degrees different from the first, “that’s a big indicator that the insulation is not effectively trapping the cold or hot air in the winter or summer.”
A quick peek into your attic might also do the trick, Craig says. If your insulation isn’t at least 12″ deep, depending on the material being used, your house isn’t meeting minimum local code requirements.
Frank Parkinson of Weatherseal Insulation Company says the type of material that’s in the attic can be confusing for some homeowners. Often they’ll need to call a professional to sort out what’s what. “A lot of homeowners, depending on the age of the home, won’t know what the existing insulation is because there have been numerous types put in over the years,” he says.
Inside the material
So what are some of the insulation materials you might have perched atop your house? Craig says in most cases it’ll be one of two materials—cellulose or fiberglass—in one of two formats—loose fill or batt.
Loose fill, true to its name, is a bunch of bits of material. Cellulose loose fill looks like gray paper—largely because that’s pretty much what it is. Fiberglass insulation, a synthetic made of limestone and potash, will be composed of strands and either pink, white or yellow, depending on the manufacturer. Batt fiberglass, a blanket-like insulation that comes on rolls, is woven strands of limestone and potash. Because of the manufacturing process, batt fiberglass is more expensive than loose fill, so the DIYer will want to go the latter route if they’re redoing insulation themselves.
“One way I explain the difference between cellulose and fiberglass—if you put a newspaper and a glass jar or bottle, which fiberglass is essentially made of, in the sun, which one is going to feel colder to the touch?” Parkinson asks. “With fiberglass, the R-values can fluctuate with the temperatures. Cellulose remains closer to the R-value.”
Cellulose and fiberglass, either loose fill or batt, are perfectly fine for reaching R38, the required minimum insulation rating for homes in Albemarle County. But for the latest and greatest, homeowners are looking to foam insulation. Open cell foam is spongy when it solidifies, whereas closed cell is denser, giving it the highest R-value on the market. But there is a cost—about three to four times that of fiberglass, according to Craig.
Parkinson says because the cost is so high, closed cell foam is generally only used in high-moisture areas like crawl spaces and basements.
Keeping it fresh
While you’re not likely to need a wholesale replacement of your attic insulation, customers opting for an upgrade to spray foam have to have a clean space for proper filling, according to Craig. An extensive roof leak might also force a homeowner’s hand—if the majority of your insulation is wet it won’t insulate properly and won’t necessarily dry on its own.
Even if you’ve got a good 12″ of dry insulation in your attic, you may still need a touch up. Not only can minor areas of wetness cause an efficiency reduction, trampled insulation is likewise compromised.
“If it starts getting compressed, especially fiberglass, [it] will lose R-value,” Parkinson says. “We look around for damaged insulation, and maybe we can just replace some of it.”
R you chilly?
R-value is a measure of the ability of insulation to resist air flow. Higher R-values mean better insulation. The minimum R-value for attic insulation as defined by local specifications is R38. “Each climate zone is different,” says Frank Parkinson of Weatherseal Insulation Company. “The farther north you go, the higher the R-value.”—S.G.