Whether you’re in the attic assessing the state of your home’s insulation or actually undertaking an insulation project, be sure to have solid footing and wear protective clothing and gear.
Live in a house for a while, and you grow accustomed to some idiosyncrasies—drafty pockets near certain walls; that room down the hall that nobody goes in, because it’s always too warm or too cold; the frequent clicking of a heat pump turning on and off.
Those quirks may be your house trying to tell you something: Check your insulation.
Your monthly utility bills may be sending the same message. If they seem too high, your insulation—be it insufficient, poorly installed, aging or absent—may be partly to blame.
Instead of wasting money heating and cooling air that leaks out of the house, spend some time evaluating how well your home is sealed and insulated. One good direction to look is up: In almost every attic, there’s an insulation problem that needs fixing.
“Even if your home was built yesterday, you should go up there and look at your insulation,” says Michael Smith, manager of energy programs for Central Electric Power Cooperative. “You will find things that need to be addressed, things that will make a difference and that don’t necessarily cost a whole lot.”
Know your R-value
If you want to improve your attic insulation, the magic number you need to know in South Carolina is R-38. This is the recommended R-value for attics in our region, says Buddy DeLozier, energy efficiency project manager for Central Electric.
The R-value of an insulating material tells you how well it resists the transfer of heat—holding heat in when it’s cold outside and keeping heat out on scorching summer days. Manufacturers must show this number on their packaging. The higher the R-value, the more effective the insulation.
“If installed correctly, R-38 is more than ample in South Carolina,” DeLozier says. “If you go higher than that, you really aren’t seeing more savings.”
Finding out whether your home is well insulated starts with looking around your attic to see what kind of insulation you have, determining its R-value and measuring its depth with a ruler. Just remember to:
- Bring a flashlight or headlamp. You’ll need to look carefully to know if the insulation is covering well. That means peering into every cranny.
- Watch your step. A good look around might mean exploring parts of the attic where you’ve never ventured—and you don’t want to step in an empty space between ceiling joists that will drop you through the ceiling below. Walk only where there’s sturdy footing.
- Protect yourself. Wear gloves, a breathing mask and eye protection. Some insulation materials, including fiberglass, will irritate your skin, lungs and eyes. For more on different types of insulation materials, see "What's in your attic?"
- Know your limitations. Avoid the attic when it’s too hot or too cold to spend time up there. If you’re not physically able to crawl around in the attic, call an insulation professional.
Here’s what to look for during an attic inspection.
Insufficient insulation: It’s not uncommon for South Carolina homes to have less than enough insulation to meet the R-38 recommendation for peak efficiency. If you can see the bare wood of ceiling joists, chances are your home falls short. Ideally, DeLozier says, your insulation should completely fill the gaps between—and cover—the joists.
An exposed joist “is just an inch-and-a-half gap in your insulation” that needs attention, he says.
The older the house, the more likely it is to lack proper insulation. Any home built before the mid-1970s almost certainly has too little insulation, but even newer homes can fall short. State building codes requiring a minimum of R-30 in new construction have only been in place since 2000.
If your attic has batts or rolled insulation, find the R-value printed on the underside of the kraft paper backing, then measure the thickness of the material. Insulation is supposed to be fluffy, Smith says. If it gets packed down, it loses some of its R-value. An R-19 batt or roll should be about 6 inches deep; R-30, about 9 inches. Loose-fill insulation should be between 10 to 14 inches deep to provide the recommended R-38 level.
If your insulation doesn’t measure up, consider supplementing what’s there. Good news: There’s no need to remove the old insulation. Two layers of R-19, for example, will bring an attic up to R-38, and blown insulation can be layered over existing rolls, batts or loose fill as needed.
Gaps in insulation: It’s possible that your homebuilder overlooked corners or awkward spaces when blowing or laying insulation, usually near the exterior walls. “That’s the edge of a room on an outside wall that feels cold all the time, and you don’t understand why,” Smith says.
Maybe you are missing insulation where a workman pushed it away to access your HVAC system, or maybe air flowing into the attic from the soffits has blown away loose-fill insulation and left bare spots. Whatever the reason, a gap in insulation means there’s a gap in your thermal barrier. Filling in small gaps can be an inexpensive do-it-yourself job, but if you find large gaps—or no insulation at all—call a professional, Smith advises.
Dark marks on the insulation: These show up as streaks, patches or dark edges, telling you that air is leaking in or out of your house and that insulation is trapping dust and dirt as air travels through it. Find and seal those leaks before adding new insulation. (See "Seal the deal.")
“You might have insulation that is acting as no more than a filter,” says Bennie Marshall, owner of Carolina Green Energy Systems. “Insulation does not stop air flow.”
Dollars and sense
Upgrading attic insulation is a relatively simple and inexpensive way to improve your home’s efficiency and comfort. A homeowner might spend about $40 for a few replacement batts to fill in empty spaces, maybe $800 to upgrade an average attic from R-19 to R-38, or up to $1,200 to have a professional blow loose-fill fiberglass into a bare attic. But homeowners should think carefully about whole-house efficiency and the long-term return on investment before investing in a major attic insulation upgrade, Smith says.
If your existing insulation is already at R-30, adding more to get it up to R-38 may not deliver noticeable savings. But an upgrade from R-19 or below will pay dividends in short order, he says.
“If you have minimal insulation now, you could easily see a return on your investment within a few years,” Smith says.
The Energy Star website from the U.S. Environmental Protection Agency offers a do-it-yourself guide with tips for sealing and insulating your home.