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Increasing the insulation in your attic or crawl space is among the most cost-effective ways to reduce a home's heat loss through the roof and building shell in the winter and heat gain during the summer. Doing so saves energy while improving comfort year-round.

Find it! Attic insulation

When choosing insulation for your attic, always look for labels indicating that a product has been certified by ENERGY STAR®, GreenGuard™, Green Seal, or another reputable green product certification program.

How to increase the insulation in your attic

1. Check the current insulation levels in your attic or crawl space. If you have less than 3 inches, then adding more insulation will likely prove cost effective.
2. Decide whether you prefer to install the insulation yourself or hire a professional. This will help narrow down your choices for insulating materials. Some types of insulation should only be installed professionally, so be ready to pay more if your material of choice falls in this category.
3. Find a green insulation service provider near you, with the following locater: Low Impact Living
4. Ensure that your planned insulation increase incorporates effective ventilation strategies within the attic to prevent moisture accumulation and mold growth.
5. Make sure to increase your insulation levels to a resistance value of at least R22, usually 6-7 inches deep, depending on the product.[1] Energy Star® recommends attic insulation levels between R-38 and R-49 for most US homes, meaning an average increase of 6-10 inches in most cases.[2][3]
6. Seal all air leaks between the attic and the interior environment below, including areas around light fixtures, wiring and plumbing penetrations, and bathroom fans, and attic access hatches or pull-down stairs.[4]

Increasing the insulation in your attic helps you go green because…

• It reduces both heat loss and heat gain through the building shell and roof, conserving energy and cutting associated costs.[5]
• It improves physical comfort levels within the home by helping to maintain more consistent interior temperatures.[6]
• It enhances air quality by helping to seal out unconditioned exterior air, which may contain dust and other impurities.
• In newly constructed homes, increasing insulation levels can enable the purchase of smaller, more efficient HVAC heating and cooling units.[7]
• Based on current building trends, it protects a new home against obsolescence, avoiding the costs of future retrofits.
• It improves the quality of new home construction by requiring thicker wall design or higher-density materials.

The US Department of Energy (DOE) recognizes roofs and attics as top priorities for energy-saving insulation upgrades due to the accessibility of most attics and the immediate improvements in both comfort and energy consumption. Between 50 and 70 percent of the energy used in an average American home is consumed by heating and cooling systems.[8]

Although there are numerous factors to consider when seeking to maximize a home's energy efficiency (see the DOE's whole-house approach), the DOE lists inadequate insulation as a leading cause of home energy waste because it forces even the most efficient heating and cooling systems to work harder and consume more energy.

Heat naturally passes from warmer objects and areas into colder ones; insulation provides a barrier to slow down this transfer.[9] Less heat transfer means more energy saved and lower pollution levels: the Rocky Mountain Institute estimates that upgrading insulation in the attic, walls, and basement of the typical American home will reduce that home's CO₂ emissions by 4,147 lbs per year.[10]

How effective is attic insulation?

While actual energy bill and emissions savings will vary based on both current insulation levels and regional climate considerations, the Rocky Mountain Institute estimates that adding insulation to your attic or crawl space alone can cut approximately 2,142 lbs of CO₂ emissions from the average homeowner's carbon footprint.[10]

Savings associated with increased attic insulation can range from 5 percent to 25 percent of your current energy bill.[11]

Subsidies and incentives

Upgrading your home's insulation—both in the attic and elsewhere—can qualify you for tax incentives at the federal, state, and local levels. For detailed information, see these resources:

• American Council for an Energy-Efficiency Economy Updates on potential energy legislation.
• Tax Incentives Assistance Project Explains federal tax credits for energy efficiency.
• Alliance to Save Energy Offers an index of energy efficiency programs by state.
• Database of State Incentives for Renewables & Efficiency Provides information on state and federal incentives.
• Contact your utility provider for information on local offers.

Related health issues

The health concerns associated with insulating an attic or crawl space are similar to those of any insulation project; homes with cathedral ceilings may require additional renovation measures to ensure adequate air flow and prevent moisture buildup.