How to Save Money With Insulation
No matter where you insulate or how much, some is better than none. Attic insulation alone can save 10 to 50% off your heating/cooling bill. A little investment now can save you years of heating or cooling costs. We share some general information on insulation.
Get in the Zone
Before you start your research or shopping, know that all insulation is classified by R-values. R-values measure the resistance to heat flow. The higher the number, the more insulating factor.
A quick way to find insulation recommendations is to go to energy.gov. There is a zone map on this site. The higher your zone number, the colder the climate. For instance, Florida is a zone 2, and Northern Minnesota is a zone 7.
Decide what type of insulation material is the best for your needs. While there are many different materials available than discussed here, the most common material is fiberglass, which is made of sand and recycled glass. Fiberglass can range from R-11 to R38. It's a good choice for any area of the house (attic, basement or crawl spaces) because if it gets wet, it will dry quickly while retaining its R-value. Fiberglass is also non-combustible. It comes in batts or loose fill. (See below for more information on batts and loose fill.)
Cellulose is made from shredded newspaper which absorbs moisture and will eventually lose its R-value over time. While cellulose is treated with a fire retardant, it is still combustible. If you go with cellulose, be sure the area you are putting it in remains dry. With cellulose you will need to purchase more to get the same R-value as you would with fiberglass.
Cotton insulation is made from recycled blue jeans. It is treated with boron which is a non-toxic fire retardant and pest repellent. Unlike cellulose, it maintains its R-value. It's available in batts.
Loose Fill vs. Batts
The two most common types of insulation include blanket (or batts) and loose fill (or blown-in).
Batts are like a thin-width blanket and come in rolls. They are so easy to install that even a novice DIYer can do it. They are packaged in rolls and come in various thicknesses. To know which thickness to use, measure your joist spacing. Batts come in 16” or 24” widths to fit between joists. They also come with or without facing, which is a vapor barrier that is attached to the back of the batts. You need a vapor barrier only if it is the first layer of insulation.
Loose fill (blown-in) requires a machine or can be hand spread. It works well if your attic has non-standard joist spacing or if it has lots of obstacles (like vents, can lighting fixtures, etc.). It also works well if your attic has a low clearance. However, it can be labor intensive compared to ease of rolling out batts.
Know Where to Insulate
Insulate attics, basements, sill plates, crawlspaces, windows, or anywhere else you may feel a draft. The attic is where most heat escapes, so start there. And don’t forget to do the back of the attic hatch. You might even think about putting weather stripping around the hatch.
You can use batts of “cut to height” insulation in the rim joist of your basement. Just don’t compress them too much. They should be snug, but not jammed into these areas. Remember, it is the air space in the insulation that gives insulation its R-value. There are many air escape holes in your basement. Check out the sill plates, wiring holes and plumbing holes. These should also have some insulation.
Crawl spaces can use batting as well. Just remember the facing will go toward the heated space. This is a trickier project as you may have to staple the batting up to keep it in place.
For windows, a great technique is to use a minimal expanding foam like Great Stuff. Be careful when using this product because it expands to fill spaces but sometimes takes a while. Experiment by spraying some on a piece of cardboard and waiting an hour to see how much it expands. Do all of your windows on the same day since the nozzle on the can will plug up if not used in the same session. Follow the directions on the can.