Microsoft Hohm: Learn how you can reduce your energy usage and start saving today

Learn how you can reduce your home energy usage and start saving today

Add attic insulation to with a high R-value to improve home heating

Learn how to add attic insulation, what an insulation R-value is, and how a well-insulated attic can improve home heating and energy efficiency.

Costs	Annual Savings	Time
DIY*: varies	money*: varies	DIY*: 6-8 hours
Pro*: varies	CO2*: varies

Difficulty	Recurrence
medium	None

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OK, attic insulation isn't exactly thrilling, but it's a vital part of home heating and cooling. Good attic insulation helps your home's envelope (as they call it) keep heat in, which is a big deal because in a typical home, over half of the energy loss is through the exterior walls, floor, and roof. Proper insulation and sealing air leaks can reduce that energy loss. Plus, your furnace or boiler might not have to work as hard—better attic insulation can lower your home energy use by up to 40 percent!

What do pirates look for in attic insulation? The arrrr value! Insulation R-value measures how well a material stops heat flow, the higher the better. The minimum required insulation R-value depends on where you live. Typically, you should insulate your attic to at least R-38, or approximately 10-15 inches, depending on the type of insulation. Increase the insulation R-value if you live in a colder climate.

If you already have attic insulation, movin' up to a higher R-value could provide more energy savings. If you decide to have extra attic insulation installed by a pro, it'll cost you roughly $.80-$1.10 per square foot. (Prices vary by region, type of insulation, and the level of accessibility of your attic.)

How To

1. Determine whether your existing attic insulation is adequate. If you can see the floor joists, add more, says Energy Star.

2. Seal any large air leaks in your attic and basement. Leaks in either place can affect insulation effectiveness.

3. If you choose to add more insulation, decide whether to DIY or hire a contractor. (The easier it is to access your attic and move around in it, the easier it will be to install insulation yourself.)

4. Buy the correct width of insulation materials. Measure the area between joists in your attic to determine this.

5. Before installing the insulation yourself, make sure you're covered to near-mummy levels with long pants, a long-sleeved shirt, goggles, gloves, and a face mask. Avoid breathing in insulation fibers or getting them on your skin and in your eyes.

Important: If your attic has vermiculite insulation, it may contain asbestos. Hey-o! Be sure to get this type of insulation tested by an approved lab before making any changes to it. Your local health department can list approved labs.

Tools and Materials

Insulation
Instructions that came with the insulation
Staple gun and staples
Work lights or flashlight
Utility knife
Straight edge
Broom handle (for positioning insulation in harder-to-reach places)
Attic rafter vents/baffles
Plywood to create a temporary walkway across the insulation

Tips and Tricks

Determine existing R-value. Insulation needs to be thick enough to keep out the elements. Have an inspector look at your existing insulation's R-value—you should have at least an R-38 for attic space (depending where you live) and R-13 for walls so your home heating or cooling system doesn't have to work as hard.
Compare contractors' bids based on R-value. Make sure contractors' bids are for the same insulating value (R-value), not just the same number of inches.
Attic access helps determine the type of insulation to use. If access to your attic is limited, blown-in cellulose or fiberglass insulation is your best bet.
Consider using cellulose insulation. If you are doing the installation yourself, consider using cellulose. Cellulose insulation is less expensive and has a higher R-value per inch than fiberglass, and it won't irritate your skin and lungs.
Check for holes in the attic floor. Make sure all holes in the attic floor are sealed before you install attic flooring insulation.
Check for a vapor retarder. Make sure there is a vapor retarder between the attic floor and the insulation to help prevent excess moisture from condensing on the insulation. However, if you are adding insulation on top of pre-existing insulation, don't install a vapor retarder, since it may trap moisture in the old insulation underneath.
Don't block the attic vents. Proper attic ventilation is important for energy saving, maintaining an R-value, and keeping your home comfortable year-round.
Check the evenness, thickness, position, and dryness of your insulation. Attic flooring insulation should be dry, uniformly thick, and distributed evenly with no gaps. The vapor barrier side should be facing downward, toward the living space you are trying to keep warm.
Before adding insulation, check for black-stained areas on the edges of fiberglass in your attic. Go into the attic and looking for black-stained areas on the edges of the fiberglass. That's dust, and it shows where air is flowing up out of the living space. Sealing that area first will do more good than simply piling on more insulation.
Observe the interaction of snow and ice with your house. Does snow melt from your roof rapidly? That means heat is escaping from your home through the roof and you should consider adding more attic insulation. Rapid formation of icicles without a thaw is another indication that you're losing heat through the roof. If you find that you are losing a lot of heat through your roof, evaluate the thickness and uniformity of the attic flooring insulation.