Attic Insulation


Making sure your attic is well-sealed and properly insulated is one of the most important things you can do as part of your ENERGY STAR Home Upgrade to reduce the air leaks that contribute to energy waste and make your home less comfortable. Count on ENERGY STAR to help you make your energy choices count for a clean energy future with information on how to measure your levels, choose the right insulation type and hire an insulation contractor.

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Low attic insulation levels and air leaks mean your air conditioning and heating systems have to work harder, resulting in energy waste, and lead to discomfort in your home during the summer and the winter. If the insulation is at or below the level of the floor joists in your attic, you probably need to add more. 

Check Your Attic Insulation Level

Step 1: Access Your Attic

  • You have it easy if you have stairs or a set of pull down-stairs going to your attic.  However, if you just have an attic hatch or cover, you may need a ladder. 
  • Bring a flashlight, a ruler or tape measure, and your cell phone to take a picture.
  • If you can see and reach the insulation on the floor from the attic hatch, you do not need to get all the way into your attic. If there is flooring around the attic hatch, you may need to crawl inside the attic to reach the insulation.
  • Some homes have ‘cathedral ceilings’ with no attic.  In this case, the insulation is placed right up against the roof deck and covered with drywall.  To address this, hire an energy auditor or insulation contractor to check the insulation level and see if more can be added.

Step 2: Check Your Attic’s Insulation Level

Once you have access to the attic, there are several quick checks that you can do to determine where you may need more insulation in your home.

  • Do a Visual Check of Insulation Levels - When looking across your uncovered attic floor, if the insulation is at or below the level of the floor joists, you probably need to add more insulation.
  • Measure Insulation Levels - Use a measuring tape/ruler to measure the depth of the insulation (inches). Record your measurement so you can determine how much more insulation you need to achieve the recommended levels.

NOTE:  Insulation levels are specified by R-Value, which is a measure of its ability to resist heat traveling through it. The higher the R-Value the better the thermal performance of the insulation.  Here are some example R-values for an attic floor.

Does Your Attic Insulation Measure Up?

Since most common insulation types (fiberglass, cellulose, mineral wool) have an R-value of about 3 – 3.5 per inch it is easy to estimate how much R-value your attic’s insulation currently has.  Just take the depth in inches x 3 to get an estimated value.

Ask the Expert Small Mark Visit Ask the Experts for more information to learn how to check your home's attic insulation level

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The type of insulation you use on your project often depends on what kind of project you are planning. Varying degrees of skill are required to install different types of insulation, which may help you decide whether it is better to hire a contractor or do it yourself.

Choosing The Right Type of Insulation

This chart provides information on different types of ENERGY STAR certified insulation, which types of projects they are best suited for, and the relative skill level needed for the average homeowner to install them.

Blanket: batts and rolls
  • Fiberglass
  • Mineral (rock, stone or slag) wool
  • Plastic fibers
  • Natural fibers (cotton, wool)
Best Suited For
  • Unfinished walls, including foundation, basement and crawlspace walls
  • Floors and ceilings
Skill Level Required
  • Basic
Foam board or Rigid board
  • Polystyrene
  • Polyisocyanurate
  • Polyurethane
Best Suited For
  • Unfinished walls, including foundation, basement and crawlspace walls
  • Floors and ceilings
  • Unvented low-slope roofs
  • Exterior continuous insulation
  • Exterior below grade foundation walls
Skill Level Required
  • Intermediate
Loose-fill and Blown-in
  • Cellulose
  • Fiberglass
  • Mineral (rock, stone or slag) wool
Best Suited For
  • Enclosed existing wall or open new wall cavities
  • Unfinished attic floors
  • Other hard-to-reach places
Skill Level Required
  • Intermediate
Rigid Fibrous or Fiber Insulation
  • Fiberglass
  • Mineral (rock, stone or slag) wool
Best Suited For
  • Ducts in unconditioned spaces
  • Other places requiring insulation that can withstand high temperatures
Skill Level Required
  • Intermediate
Sprayed Foam and Foamed-in-place
  • Cementitious
  • Phenolic
  • Polyisocyanurate
  • Polyurethane
Best Suited For
  • Enclosed existing wall
  • Open new wall cavities
  • Unfinished attic floors, attic ceilings
Skill Level Required
  • Advanced (Certified Installer Needed)
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You can spend less on your attic sealing and insulation project by taking advantage of federal tax credits and utility rebates offered in some parts of the country.  Special financing programs are also available for low-to-moderate income families.

Financial Incentives

Rebate Incentives

Rebates for air sealing and insulation may be available through your local utility company. Check the web site of your local utility and visit the ENERGY STAR Rebate Finder and enter your zip code to see what incentives are available in your area.  You can also check with your contractor to see if they know of incentives or rebates in your area.

Federal Tax Credits

There are currently Federal tax credits for the cost of  insulation (only) for up to 30% of the cost not to exceed $1,200.  Products that air seal (reduce air leaks) can also qualify, as long as they come with a Manufacturers Certification Statement, including:  weather stripping, spray foam in a can designed to air seal, and caulk designed to air seal.  The Federal tax credit for residential energy efficiency applies through December 31, 2032. Learn more about this tax credit.

Assistance for Low-to-Moderate Income Families

The Department of Energy (DOE) offers a Weatherization Assistance Program (WAP) available for households with lower incomes that qualify for Supplemental Security Income, Aid to Families with Dependent Children, and other income eligibility criteria. This program includes a home energy assessment and common home improvements such as sealing air leaks and insulating the home attic.  You can also contact your local electric utility to see if they offer energy efficiency home upgrades for low-income customers.

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Crawling around in a dusty attic is not for everyone and most people prefer to hire someone to do the work for them. Here are some things to consider when hiring a contractor.  If you would prefer to do the work yourself, there are also tips to help you do the job.

Tips For Hiring A Contractor

Find and Address Hidden Problems

Attics can have hidden problems that can be tricky to solve.  Here is a list of problems and indicators where it is recommended to hire a professional to correct these problems before proceeding:

  • Difficult attic access and limited space to work
  • Wet or damp insulation, indicating a leaky roof
  • Moldy or rotted attic rafters or floor joists, indicating moisture problems
  • Kitchen, bathroom, or clothes dryer vents that exhaust moist air directly into the attic space instead of outdoors
  • Little or no attic ventilation
  • Knob and tube wiring (in homes from the 1930s and earlier), which can be a fire hazard when in contact with insulation

Prepare to Call a Contractor

Before calling a contractor, gather the following information about the project:

  • How many inches of insulation you currently have on your attic floor?
  • What are the approximate dimensions of your attic floor in feet?  (for example: 24 ft x 32 ft)
  • Do you have an attic hatch, pull-down stairs, or other way to access the attic?
  • You may be able to send the pictures to the contractor. So, if you can safely stick your head up into the attic, take a few pictures with your cell phone. 

Shop Around When Selecting a Contractor

Insulation contractors have all the equipment and experience to do the job right and often do it much quicker.  As with any home improvement project, you want to make sure you’re getting a good price and that the work will be done right.  A good contractor has a license to work in your state, has insurance, and is trained and certified to do the work.  Start by checking with your local gas or electric utility. They may offer incentives to do the work and provide pre-screened lists of licensed and insured contractors on their websites.  Other helpful contractor lists include:

Building Performance Institute (BPI)

  • Contractors are pre-screened by BPI and are licensed and insured
  • BPI has national training and certification standards that contractors must meet

Owens Corning Certified Energy Experts (CEE)

  • Contactors are pre-screened by Owens Corning and are licensed and insured
  • Owens Corning has training and certification standards as well as offers warranties.

Talking to Contractors on the Phone - When you call a contractor or send an email for an appointment, here are some things to ask/confirm:

  • The contractor is licensed and insured in your state.
  • The crew is trained and certified to do insulation work.
  • Make sure the contractor understands you want attic holes and gaps sealed before any insulation is added.  If they do not agree to “seal before insulating”, call another contractor! 
  • Tell the contractor what type of attic entrance you have (hatch, stairs, door) or if they must make a new opening
  • If needed, ask if they offer attic hatch covers or attic door insulation and request an estimate.
  • Let the contractor know if you have an older house (1930s or earlier) and whether there could be ‘knob and tube’ wiring in the attic.  It you are not sure, just tell them how old your home is

Many contractors will want to conduct a site visit for a more accurate cost and scope of work estimate.  To help ensure you are getting the best deal, get estimates from several different contractors. You can compare costs and scopes of work to help ensure they will do a complete job.

Making sure the job is done right

Once you hire a contractor, it is a good idea to make a few requests of the contractor and crew to help ensure you are satisfied with the job.  You should also understand what work they will be doing.

The Day of the Job - When the day of the job arrives, here are a few things to ask the contractor and crew to do to help ensure the job meets your expectations.  Be polite, but insistent that they do these things:

  • Wear shoe coverings to keep your house clean during the work.
  • Vacuum up any dirt or spilled insulation.
  • Notify you if there is any wet insulation or roof leaks they notice.
  • Notify you if there are any signs of pests (birds, mice, or squirrels) living in the attic.
  • Take a few pictures of the attic floor with your phone/camera before beginning any work so you have a record of what was there before they begin. 

Make Sure the Job’s Done Right

When hiring a contractor, make sure that you clearly understand the work they’ll be doing.  Don’t hesitate to ask questions before the contractor starts and stay involved throughout the process! Here are some tips to keep in mind:

  • warningIf there are any appliances or equipment in the attic that burn a fuel, like a gas water heater or furnace, have a professional HVAC contractor conduct combustion safety testing after any air sealing.
  • Any project estimate should also include installing insulation baffles (rafter vents). This ensures that as you add insulation, soffit vents (which allow outside air to enter the attic) are not blocked and your attic has proper air flow.
  • Contractors should seal air leaks in the attic floor before adding insulation.  It’s much easier to seal first to ensure you get the full performance out of your insulation.
  • If you have air ducts in the attic, make sure contractors do not step on or damage them. 
  • Burying any ducts on the floor in insulation is OK to do – it can even improve efficiency.  Just make sure the ducts are well sealed first.
  • Unless your old insulation is wet, moldy, smelly, or contains animal waste, contractors can just add new insulation on top.  It is usually not necessary to remove existing insulation.
  • If you have older recessed light fixtures (can lights) that stick up into the attic floor, the contractor should cover and seal them using specially designed covers before installing insulation. The covers are available at most home improvement stores.
  • Almost every home has a plumbing vent pipe which passes through the attic.  The contractor should seal the chase (hole) for the plumbing vent pipe.
  • Almost every home has a chimney or flue for hot gasses from the furnace, boiler, or fireplace.  The gap around the flue to chimney can be sealed with metal flashing and high- temperature caulk.
  • It is important to weather strip and insulate the attic hatch or door.  Alternatively, there are several off-the-shelf attic hatch insulation products available for standard-sized openings.
  • Most contractors use blown-in, loose fill insulation for attic floors, which is quick and easy to install with the right equipment. Typical materials include fiberglass or cellulose – both contain some recycled content (glass or ground up paper) and are inexpensive and safe.  If traditional insulation rolls are used for the attic floor instead, be sure that it is “unfaced” (no foil or paper backing needed) so moisture does not get trapped.

End of the Job

The contractor is required to provide you with documentation at the end of the job to show how much insulation has been added and what the new insulation R-value is for your attic.  When it’s done, take a picture and compare it to the pictures you took earlier to see the improvement. Then, you can sit back and enjoy knowing your home is more comfortable and energy-efficient.

Do-It-Yourself Insulation Installation Tips
If you are handy, have a vehicle that can haul some insulation rolls or batts (or even a blowing machine), and are ready to get a bit dirty, you can save more by doing-it-yourself (DIY) with some ENERGY STAR DIY resources to help you get the job done.
Safety First – If you are going to do this project yourself there are several heath and safety considerations to keep in mind:

Safety Equipment

  • Safety glasses, gloves and dust mask/protective face mask
  • Flashlight or portable safety light
  • Boards to walk on, if needed
  • Hard hat or cap to protect head from sharp roofing nails

Materials and Tools

  • Insulation
  • Retractable utility knife and sheet metal scissors
  • Tape measure
  • Straight edge for cutting

Tips and Safety Considerations

  • EPA recommends that you complete an attic sealing project before doing this project.
  • Gather all your tools and supplies before you begin to minimize trips into and out of the attic.
  • Be sure that the work area is well lit by using a drop light, and keep a flashlight handy.
  • During hot weather, start working early, as attics heat up as the day goes on.
  • Drink plenty of water.
  • Wear a lightweight disposable coverall, gloves and hat to keep itchy and irritating insulation off your skin.
  • Wear kneepads for attics that require crawling.
  • Watch out for nails pointing up through the ceiling or down from roof deck.
  • Walk on joists or truss chords, not exposed ceiling drywall or insulation, to avoid falling through the ceiling.

warningSome attics have vermiculite insulation, which may contain asbestos. Vermiculite is a lightweight, pea-size, flaky gray mineral. Do not disturb vermiculite insulation unless you have had it tested by an approved lab to be sure that it does not contain asbestos. Contact your local health department for the name of an approved lab.

Guidance on DIY attic air sealing can be found here

Guidance in DIY attic insulation can be found here