Attic Insulation

Insulation Works Best With Proper Sealing

Before new or additional insulation is installed in the attic, you should always seal all of the air leaks.

Insulation works best when air is not moving through or around it, so it is very important to seal air leaks to ensure that the best results. According to the Department of Energy, proper air sealing and insulation can reduce your home's heating and cooling costs by as much as 30 percent! Simply adding insulation without air sealing first will only give you marginal improvements.

Insulation slows the movement of heat. When the right amount is correctly installed,insulation can deliver dramatically improved comfort and lower energy bills during the hottest and coldest times of the year.

Attic insulation

However,in most homes the insulation was either not properly installed or not installed at all in certain areas.

It is very common to see situations like the picture shown on the left that has little or no insulation in the attic. If you ever go into your attic, look around. If you see your ceiling joists, you need additional insulation.

The infrared camera image on the right illustrates a section of the attic that is missing insulation. This was taken in the winter so it shows where the cold attic air (in blue) is cooling the room because no insulation exists in this section of the attic.

Insulation Air Sealing

Coupled with the leaky window(look for the blue color in the window frame), this part of the bedroom will always be cold in the winter and hot in the summer until it is corrected.

Insulation performance is measured by R-value — its ability to resist heat flow. Higher R-values mean more insulating power. Different R-values are recommended for walls, attics, basements and crawlspaces, depending on your area of the country.

GreenHomes typically recommends from R-40 to R-60 in attics to maximize comfort and energy and utility bill savings.


Poorly insulated homes are uncomfortable and waste enormous amounts of energy.Unfortunately, the fact is there are very few homes in U.S. that are sufficiently insulated.

The image on the left was taken with an infrared camera in the winter. It is clear to see by the red and white areas of the roof that a massive amount of heat is rising into the attic from the living space. Essentially, the homeowner is paying the utility company to heat their attic. The goal is to have a cold attic in the winter – you want all the warm air to stay in your living space.

Heat flows naturally from a warmer to a cooler space. So in the winter, heat moves directly from all heated areas to unheated attics, garages,basements, and even to the outdoors. It can also move indirectly through interior ceilings, walls, and floors — wherever there is a difference in temperature. During the summer, heat flows from the outdoors to the interior of a house and also radiates down from the attic where there is insufficient insulation.

GreenHomes will also recommend the best type of insulation for your home – typically either recycled cellulose or spray foam. Both these materials are environmentally friendly and help you contribute to a greener planet.

Some of the advantages cellulose insulation typically has over other materials include:

  • It is made of 80% post-consumer recycled newsprint so it is "green".
  • The fiber is chemically treated with non-toxic borate compounds to resist fire, insects and mold
  • It has a better resistance to air convection due to its higher density

More important than the type of insulation you use is how it is installed.Ensure your insulation project is done correctly by calling the expertsat GreenHomes! We've performed air sealing and super insulatedthousands of homes across the U.S.

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