How Effective is Your Home Insulation?
Few things in a home have a greater impact to your comfort and monthly utility bills than your insulation. Consider this; roughly half of your home’s energy use is for heating and air conditioning. Homes that allow that conditioned air to escape use more energy. A leaky drafty home simply costs more money and creates a larger carbon footprint than necessary. Modern homes are designed to be more air tight than ever which means less conditioned air is lost to the outside.
If your home or office is more than a few years old, we’ve got a number of tips to help you save on your heating and cooling bills. Adding insulation may be an excellent way to improve your home’s efficiency. Here are some basics to look out for before you get started.
What Insulation Does For Your Home?
Insulation reduces heat loss from conduction in your attic, floors, and walls. It’s the insulation that makes a home more comfortable. The two most common types of insulation are:
- Loose-fill which is usually blown-in material (cellulose of fiberglass).
- Blanket insulation.
What to Do Before Adding Insulation?
Insulation is only beneficial if the house is sealed tight. This means all cracks, windows, lighting fixtures, attic joints, electric outlets, and light switches need to be properly sealed. If not, the air will still leak into your attic space and keep in mind any air that leaks up is replaced with air from the outside. Here are some basics to look out for before you start to add more insulation:
- Weather strip windows & doors – this stuff isn’t just for winter months!
- Remove window AC units in the winter.
- Have a licensed professional inspect your attic space to ensure it is properly sealed.
Skipping these steps means you may see little to no benefits from added insulation.
Now You’re Ready to Add Insulation.
You will need to verify what is required in your area. Nashville Tennessee for example, requires attic insulation R-value of between R-38 and R-60. Anything less than 38 needs to be increased. R-value is simply a measure of thermal resistance of a substance. The higher the R-value, the greater insulator a product is.
Here are the standard R-values per inch for the most frequently used forms of insulation:
- Blown Fiberglass: 2.2 – 2.9
- Blown Cellulose: 3.1 – 3.8
- Rock Wool (loose): 2.2 – 3.3
- Fiberglass batts: 2.9 – 3.8
- Sprayed Foam: 3.6 – 8.2
Here are the general recommendations for other climates. For general insulation recommendations in your area, visit the DOE Zip Code Insulation Calculator.
Warm Regions (R-30 to R-49):
- Blown Fiberglass: 14” – 18”
- Blown Cellulose: 11” – 13”
- Fiberglass batts: 11” – 14”
Mild Regions (R-38 to R-60):
- Blown Fiberglass :17” – 22”
- Blown Cellulose: 13” – 16”
- Fiberglass batts: 13” – 17”
Cold Regions (R-49 to R-60):
- Blown Fiberglass: 19” – 25”
- Blown Cellulose: 14” – 18”
- Fiberglass batts: 14” – 19”
Here’s How to Measure Your Home’s Current R-value.
- Measure the depth of your current insulation. Use an average from several places in the room.
- Identify what type of insulation you have in place today and what its R-value is.
- Calculate your R-Value.
Inches of insulation * Current Insulation R-value = Total Insulation R-value
For Example: 10 ″ insulation depth * 2.2 R-value = 22.0 R-value for your space.
Time to Add Insulation.
The first thing to do once you know your home’s current R-value is to verify what the current building code requirement is. A do-it-yourselfer can easily improve the areas of the home you can reach; however, you should contact a professional if you are looking to improve the level of insulation in your exterior walls.
What Type of Insulation is Right for You?
Walls: For improvements to exterior walls, the product of choice is fiberglass batt. It is installed during the building of your home. If you have an older home, it is possible to add blown-in insulation through holes drilled into the wall.
Rolls and batts are also popular with anyone looking to do-it-yourself. These are the popular Owens Corning “Pink Panther” products you see at local home improvement stores. They can be easily rolled into place and offer R-values up to 21. Just be sure to follow proper installation instructions.
Attic: When it comes time to improve your attic insulation, the most common form is blown-in cellulose. This material is installed using a large hose and is literally blown into place to the desired depth. Considerations include:
- Ensure proper air barriers / wind baffles are installed. This will help prevent ice build-up in the winter months as well as control moisture build up.
- Ensure the attic is properly air sealed prior to doing any insulation installation.
- Ensure recessed lights are properly sealed. You wouldn’t leave a 3-inch hole in your front door during the winter, so don’t leave one into the attic. Ensure you or your contractor is properly following fire-rating requirements for insulation installation.
Foundation: Requirements for foundation walls vary by region. Many regions require no insulation so again, check with your local officials.
How you tackle a project like this depends on your needs, experience, and budget. A home that needs the windows sealed could easily be handled on your own. If you find yourself trying to remedy a poor quality installation job where the attic wasn’t properly sealed, you may need to get a professional. It all depends on your needs.
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