This post is contributed by Joe Truini, guest blogger at The Home Depot.

Part 2 of our DIY Home Energy Audit Series

Yesterday, we showed you how to check for drafts around your home. The next step in your energy audit is to evaluate your insulation and ventilation.

Insulation is key to ensuring your home is energy efficient. Without proper insulation, you could be losing a great deal of energy through your ceiling and attic, where the majority of air usually escapes.

“Recessed light fixtures in ceilings — especially when they protrude up into an attic floor frame — can provide an undetected path for leakage of heat and air,” says Michael Chotiner, a former general contractor and contributor to numerous home improvement publications. “You can often see evidence of such leaks in patches of dirt and dust that collect on attic insulation in proximity to a fixture, and they can have considerable impact on your energy bills and comfort.”

To stop any leaks, Chotiner suggests covering the fixture. “You can’t bury a fixture under insulation that is not IC-rated (IC stands for “insulation contact”) or otherwise impede heat dissipation around it — that would create a fire hazard,” he says. “But you can build a box, place it over a recessed fixture, and secure it with spray-foam adhesive to close off air pathways safely.”

Chotiner also advises checking junction boxes for air leaks. “Junction boxes for outlets and switches mounted on perimeter walls of a home are prime locations for drafts and energy loss — even in insulated walls. You can stop the drafts and prevent losses by injecting spray foam around the boxes and installing gaskets under switch and receptacle trim plates.”

Additionally, the ventilation ducts inside the home (whether they are on the ceiling or in the floor) could have gaps and you could be losing energy there over time.

How to check your current insulation

Pro tip: Before you start, have a flashlight on hand for examining potential issues in the attic and a tape measure or ruler for measuring insulation levels.

1. Know your material
Difficulty level: easy DIY

First and foremost, knowing what sort of insulation you have is important when repairing or filling gaps. The 2 most common forms of insulation in the attic are fiberglass and cellulose blown-in insulation.

  • Fiberglass insulation is lightweight and doesn’t settle. Typically, it’s white or pink and billowy. Fiberglass is the most commonly used type of insulation, but it isn’t as energy efficient as cellulose.
  • Cellulose insulation is usually recycled paper. It settles a bit more because it’s denser, but it’s also more environmentally friendly in the long run, both because it’s a nontoxic recycled product and because it has better insulation rates. It’s also better at slowing down the air flow, which means it’s more efficient during cold weather. And cellulose is treated with a flame retardant to prevent it from becoming a fire hazard.

Some attics may be insulated with “batts” or rolls of insulation. If any of these are torn or missing, you may want to call a professional to replace them. Chotiner also notes that upgrading your insulation may prove better in the long run because loose-fill and batt insulation (cellulose and fiberglass) in exterior walls, ceilings, and basement perimeter walls can eventually get damp and/or settle, losing their insulating ability. Chotiner recommends expanded polystyrene and spray foam insulation (both waterproof) when budgets allow.

Do you have enough insulation?

Once you figure out what sort of insulation you have in your attic, it’s time to see if you have enough in place.

a. Locate the hatch or attic entry (bring your flashlight!).

b. Measure the average depth of the attic insulation with a ruler and make sure it’s the appropriate R-Value.

  • R-Value is a measure of insulation’s ability to resist heat traveling through it. You can use this calculator to estimate your attic’s R-Value. The higher the R-Value, the better the thermal performance of the insulation.

The depth of your insulation depends on the region in which you live. Consult the diagrammed map below to make sure you have the appropriate R-Value.

Map of the United States showing different temperature zones for insulation purposes


Zone Add Insulation to attic Floor
Uninsulated attic Existing 3–4 inches of insulation
1 R30 to R49 R25 to R30 R13
2 R30 to R60 R25 to R38 R13 to R19
3 R30 to R60 R25 to R38 R19 to R25
4 R38 to R60 R38 R25 to R30
5 to 8 R49 to R60 R38 to R49 R25 to R30

c. Make sure the insulation is evenly spread and there aren’t any missing or open areas. During installation, be sure to wear gloves, a long-sleeve shirt, pants (not shorts), eye goggles, and a dust mask.

Pro tip: To protect yourself from the itchy glass fibers, dust your neck and wrists with a liberal coating of baby powder. The powder will help prevent the fibers from sticking to your skin, even when sweaty.

How to install your insulation

2. Installation
Difficulty level: moderate (call a pro!)

If your attic insulation isn’t up to speed, it’s time to decide whether or not you want to blow in the insulation yourself or have professionals do the job.

You’ll need to rent an insulation blower, which breaks apart the insulation and pushes it through a hose into the attic. Typically, the hose is 100 feet long, so it can reach throughout the entire attic.

Caution: If you’re walking around in your attic, make absolutely certain that you can see the floor or the beams you’re stepping on. This may require pushing insulation out of the way. If you miss a step, you could end up falling through your ceiling. The best way to avoid this is to hire professional insulation installers to take care of the job.

In your quest to become a home maintenance maven, Check out the rest of our DIY audit series, where we go over leaks and drafts, heatinglighting, and electric appliances. Then, you can prevent home disasters.

Joe Truini writes extensively about DIY home remodeling and repair, including performing energy audits to evaluate efficiency. He has worked as a remodeling contractor, cabinetmaker, and union carpenter. Joe is the author of 8 home improvement books, including Building Sheds and Stanley Homeowner’s Guide to Tiling, both published in 2016. He also writes for The Home Depot on home improvement topics like installing storm windows.

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