How to check your attic insulation and air leaks before winter

Before you spend thousands of dollars on a new heat pump, it is worth spending 20 minutes in your attic. The EPA estimates that sealing air leaks and adding insulation saves homeowners an average of 15% on heating and cooling costs, or about 11% on total energy costs. It can also mean fewer drafts and less outside noise, dust and pollen.

ENERGY STAR describes the gaps in a typical home as adding up to a window left open every day of the year. Here is how to check your own home using its guidance.

Step 1: Gather a flashlight, a ruler or tape measure, and your phone for photos. Wear gloves, safety glasses and a dust mask.

Step 2: Open the attic hatch or pull-down stairs. You often do not need to climb all the way in. If you can see and reach the insulation from the opening, that is enough. If you do go in, walk only on the joists or truss chords, and watch for nails poking through the roof deck.

Step 3: Do the joist check. Look across the attic floor. If the insulation is level with or below the tops of the floor joists, you probably need more. If the joists are buried and you cannot see them, you probably have enough. Check the edges along the eaves, where insulation is often thin.

Step 4: Measure and estimate. Measure the depth in inches. Common types like fiberglass, cellulose and mineral wool give about R-3 to R-3.5 per inch (R-value measures how well insulation slows heat), so multiply the inches by 3 for a rough number. For example, 6 inches is roughly R-18.

Step 5: Compare. ENERGY STAR suggests at least R-38, about 13 to 14 inches, in southern climates and R-49, about 16 to 18 inches, in northern ones. It suggests adding insulation if you are more than 4 to 6 inches short or the joists are not buried. In the example above, 6 inches would be 7 or 8 inches short of R-38.

One caution: if your attic has vermiculite, a loose, pebble-like insulation, it may contain asbestos. Leave it alone until an approved lab tests it. Your local health department can recommend one.

Next, look for air leaks. Leaks into the attic, through the foundation and around windows and doors matter most. ENERGY STAR suggests a few simple tests:

The paper test: close a door or window on a sheet of paper. If it slides out easily, air is getting through.

The light test: at night, have someone outside shine a flashlight along suspect gaps while you watch from the attic or crawlspace with the lights on. Light coming through means a leak.

The smoke test: on a cool, windy day, turn off gas furnaces and water heaters, close windows and flues, and run your exhaust fans. Hold a stick of incense near outlets, light fixtures and window edges. If the smoke wavers or gets pulled sideways, you found a leak.

To check walls, turn off power to an outlet, confirm it is dead with a voltage tester, remove the cover and shine a flashlight into the gap around the box to see whether insulation is there.

Many small gaps can be sealed yourself with caulk and weatherstripping. For hidden leaks or a full picture, a home energy audit from a professional can find problems you cannot see and flag safety issues, which is a good idea before any big heating or cooling purchase.

Today's step: open your attic hatch with a flashlight and take one photo of the insulation next to a joist. That single picture answers the most important question.