Nineteen Insulation Facts Every Homeowner Must Know

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Having an adequate amount of attic insulation in your home is one of the most cost-effective ways to save on your energy costs. In addition to the return on investment benefits, attic insulation works to keep your home warm in the winter and cool in the summer, meaning year-round comfort for you and your family. 

However, almost 90% of homes do not have enough attic insulation. As the saying goes, "out of sight, out of mind." Don't make the mistake of not reaping the benefits from the right amount of insulation for your home. Here are nineteen facts that every Oklahoma homeowner should know about attic insulation. 

Table of contents

  1. What is R-value?
  2. How does insulation help in the summer?
  3. How does insulation help in the winter?
  4. How do I know if I have enough insulation?
  5. What are the different types of attic insulation?
  6. Which kind of insulation should I get for my attic?
  7. Does attic insulation have asbestos?
  8. Can attic insulation make you sick?
  9. How can attic insulation help with indoor allergies?
  10. How long does attic insulation last?
  11. How much insulation do I need?
  12. Are there rebates for attic insulation? 
  13. Can you have too much attic insulation?
  14. Why is attic insulation not a DIY project?
  15. When to replace attic insulation?
  16. Is attic insulation flammable?
  17. How much money can attic insulation save me?
  18. Can I remove attic insulation myself?
  19. How does attic insulation affect ice dams?

19 Attic Insulation Facts PDF


1. What is the R-value?

According to, “R-value is a measure of insulation’s ability to resist heat traveling through it.” The higher the R-value, the more resistant the insulation is to allow heat to pass through it. Different parts of the country require different levels of insulation that takes into account the average climate.


Photo courtesy of EnergyStar. gov

A majority of Oklahoma is in Zone 3 according to the map above. This means that an uninsulated attic should have an R-value of R30 to R60.

R-value is calculated by a few different factors including the type of insulation, thickness, and density as well as temperature, aging, and moisture accumulation. As a general rule, one inch of blown-in fiberglass insulation is equal to an R-value of about 3.1-3.4.


2. How does insulation help in the summer?

Your attic insulation helps to maintain the temperature in your home all year long. In the summer your attic insulation helps to keep the cold air in from your air conditioner while also helping to reduce the hot outside temperature from entering your home from the roof.

The proper amount of attic insulation in your home can help take some of the load off of your AC unit by keeping the cold air in, helping you save money on your cooling costs.


3. How does insulation help in the winter?

Just like in the summer, attic insulation works to keep the inside air in, and the outside air out. However, it also acts as a moisture barrier between the wood structure of your roof and the indoor condensation.

In the winter, when the air’s ability to hold water decreases,  moisture and condensation can build up inside your house due to cooking, showers, and other activities. Insulation provides a barrier between the built-up moisture and the cold wood surfaces in your attic.


4. How do I know if I have enough insulation?

The Department of Energy estimates that 90% of homes have inadequate insulation. If you live in an older house, the chances are that the amount of insulation is no longer up to building codes. Here are six signs that mean your home is under-insulated:

  1. Some rooms are colder than others
  2. Ice dams on your roof
  3. You spend more on heating and cooling than the average household in your area
  4. Indoor drafts
  5. The ceiling beneath the attic feels cold in the winter and hot in the summer
  6. You can see the floor joists in the attic


5. What are the different types of attic insulation?

Batts- Large strips of insulation that usually come in rolls. They come in various thickness levels and material. A common issue with insulation batts is that they do not fill in the entire attic space. They work best in areas with few obstructions or penetrations. Batts are available in fiberglass, cellulose, material wool, and cotton.

Spray Foam – Perfect for filling small gaps and cracks around doors, windows, and vents. The foam when applied expands and becomes hard once dried. A unique benefit to spray foam is that it does not allow moisture to pass through, making it difficult for mold to grow. Spray foam insulation is typically the more expensive option.

Blown-In – This type of insulation is made of smaller pieces of fiberglass or cellulose insulation that is blown into the attic through a large hose. The small, fluffy pieces of insulation fill in all of the nooks and crannies of the attic space ensuring a thick layer of insulation. It’s great for areas with existing insulation since it can be easily covered with blown-in insulation.


6. Which kind of insulation should I get for my house?

This answer depends on your attic. Do you have a lot of penetrations and small gaps that need to be filled? Alternatively, is your attic a wide open space? How much insulation do you need? Do you have existing insulation that needs to be removed or can the new insulation go on top of the current?

At Red River Roofing & Construction, we use Owens Corning Blown-In ProPink L77Loosefill Insulation. We recommend this type of insulation for these reasons:

  • The blown-in insulation is specially designed never to settle
  • R-value stays the same over time
  • It’s resistant to moisture, fungus, and mold growth
  • Only takes a few hours to install
  • Easily covers existing insulation and fill in small gaps
  • Non-combustible
  • Offers the best return on investment

 19 Attic Insulation Facts PDF


7. Does attic insulation have asbestos?

Before 1990, Vermiculite insulation was popular insulation installed in homes and may have been contaminated with asbestos. It was often sold under the brand name Zonolite. If your house was built before 1990 and contains vermiculite insulation, it is crucial that you do not remove the insulation yourself.


Photo courtesy of Steer Environmental

Ways you can tell if you have asbestos-containing insulation:

  • Insulation color is brown-gray or silver-gold
  • Insulation particles appear to have an accordion-like texture or look like popcorn or small stones
  • The loose-fill insulation seems compressed and firm

There are DIY kits available to test for asbestos. It’s important to keep children and material away from the insulation. Best practice is to limit any disturbances to the insulation that could potentially release the fibers into the air and contact an asbestos contractor.


8. Can attic insulation make you sick?

As discussed above, before 1990, some versions of fiberglass insulation sold under the name Zonolite contained asbestos but has since been phased out.

Roof leaks can be a source of mold growth in your attic, especially if the insulation in your attic isn't mold-resistant. Check your insulation for any signs of dampness or schedule a free, no-obligation insulation and roof inspection with us.


9. How can attic insulation help with indoor allergies?

Attic insulation can help to reduce the number of allergens that circulate in the air of your home. Closed-cell insulation is very useful in lessening the symptoms of indoor allergies by creating an air and vapor barrier that prevents mold growth. It also limits the amount of outdoor air that can penetrate indoor living spaces.  


10. How long does attic insulation last?

According to the International Association of Certified Home Inspectors, spray foam insulation, cellulose, loose-fill, foam board, and rock wool insulation can last up to 100 years. Factors such as roof leaks, the quality of the installation, moisture absorption, pests, and mold can play a part in the reality of how long your insulation may last.


11. How much insulation do I need?

That answer depends on where you live, what kind of insulation, the attic space to be covered, budget, and the optimal energy-savings. The Department of Energy recommends a minimum amount of R-38 level of attic insulation.

pillar_howmuchHowever, you also should take into account the age of your home to ensure that your attic is properly sealed from the elements.


You can calculate the amount of insulation needed for your home with this Insulation Calculator by Owens Corning.


12. Are there rebates for attic insulation?

Many municipalities offer attic insulation rebates to help offset the cost of insulation. It benefits your community when the overall energy consumption is less. Insulation is one of the most cost-effective ways to improve your home’s energy efficiency, and rebates are offered to entice more homeowners to take advantage of this money-saving solution.

Within Oklahoma, you can earn up to $500 in energy rebates if your insulation is installed by an approved contractor. Check out our list of local energy rebate programs.


13. Can you have too much attic insulation?

Your attic should have enough space to circulate the air and allow for the home’s natural expanding and contracting. If your home is too tightly sealed, moisture will have trouble escaping and lead to mold and mildew.

Some homeowners, unaware of the calculation involved in surface space, vent space, and net airflow, assume that the more insulation, the more energy-savings. This miscalculation has the DIYer blocking necessary ventilation, covering rafters, and recessed lighting. These mistakes can create fire hazards, reduce energy-efficiency, and essential airflow.


14. Why is attic insulation not a DIY project?

As mentioned in the previous section, some ambitious homeowners may cover vents, lighting, and other areas with insulation that will block airflow and cause fire hazards. Another situation may be the miscalculation of too much or too little insulation for the attic space as well as not correctly sealing air leaks around pipes, cables, and other small areas.

By installing insulation yourself, you also may lose out on energy rebates that require an approved contractor to install. Safety is also a concern for any DIY project. If you’ve never installed attic insulation, you may not be aware of specific safety precautions that can prevent you from falling through the attic or becoming exposed to hazardous materials.

Contracting with a professional insulation installer gives you the peace of mind that your insulation is being installed correctly, safely, and it enables you to take full advantage of those energy rebates. Not to mention it frees up your time to spend on projects you’d rather be enjoying.


15. When to replace attic insulation?

Most often new insulation can be installed over the current installation, but there are some cases when the old insulation should be removed entirely:

  • The insulation is wet
  • The insulation is moldy
  • There is evidence of pests living in the insulation
  • Your insulation was installed before 1990 and may be contaminated with asbestos



16. Is attic insulation flammable?

Most insulation is now manufactured to be flame-resistant, however, if you live in an older home, it’s possible that your insulation may not be. Rock wool, loose-fill, and fiberglass batts without paper backing are safe, fire-resistant alternatives.

According to the Insulation Institute, fiberglass and mineral wool insulation are made from noncombustible materials, whereas cellulose is primarily made from newspaper and although heavily treated with a fire-retardant, it is still recognized as a fire hazard by the Consumer Product Safety Commission. The Insulation Institute also notes that spray foam insulation will ignite at 700 degrees F.

19 Attic Insulation Facts PDF


17. How much money can attic insulation save me?

There are many variables such as the size of the house, the age of the house, energy usage, type of insulation, rebates and financing, involved in calculating savings for your home. However, we can provide an estimate for a 2000 sq. ft. home in Oklahoma.


On average, to finance through our Green Sky non-secured financing, the average payment for this same $1500 project is a $20.60. If you’re already receiving an average of $40 monthly in utility bill savings, this gives you an extra $20 in your pocket every month.  

To add to the savings, power companies in most municipalities are offering an energy rebate of up to $500 with an approved application.


18. Can I remove attic insulation myself?

It isn’t often that you will need to remove the attic insulation from your home entirely. If in a rare case you do, it’s best to contact a professional. The old insulation must be appropriately discarded, and your attic space must be completely clear of the insulation.

The last thing you’d want to is release mold spores into the air or send pests and eggs scurrying throughout your home. Put your family’s safety first and hire a professional to rid your home of the insulation.


19. How does attic insulation affect ice dams

Ice dams develop in the presence of three significant factors: snow, heat to melt the snow, and cold temperatures to refreeze that melted snow into ice. Buildings that are poorly insulated cannot prevent heat inside the building from reaching the roof. For this reason, they are more susceptible to ice dams.

If your attic is too warm because of insufficient insulation, the snow on your roof melts quickly and pools into your gutters. Once the water reaches your gutters, it refreezes, and ice builds in your gutters. This blocks the path for water to escape off of your roof. Instead, ice builds up and pushes water up your roof and under your shingles, eventually leading to a roof leak.


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19 Attic Insulation Facts PDF

Talk to an insulation expert on how you can save money on your monthly energy bills. Schedule your free, in-depth insulation consultation today.  

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