The insulation R-value is a measurement of the resistance of heat transferring through insulation material. To explain r-values: a higher number indicates better resistance. These values are determined in laboratory tests to have a standard for measuring all insulation products. Unfortunately that doesn’t tell you everything you need to know. As temperature changes occur, products react differently causing R-values to change. In the case of fiberglass, up to 50% is lost when temperatures drop, whereas cellulose insulation actually increases in performance.
Here is valuable information provided by Ken Campbell of House to Home Interiors that may save you money. The US Department of Energy recommends that homes in our region should have an R-value of 49 in the attic. There are other aspects to be considered as well:
Convective heat loss is a phenomenon that starts at about 32 degrees Fahrenheit. In blown fiberglass, air begins to circulate within the insulation, which ultimately causes heat to be carried off through these airflows. This means the R-value is greatly reduced.
Although glass fibers do not absorb moisture, through these airflows moisture can condensate into the insulation and migrate to parts of the insulation assembly that may become damaged.
Installing cellulose insulation over existing fiberglass will improve the performance of the fiberglass and correct this problem.
If we talk about safety, fire resistance is an added benefit for cellulose insulation. Homes insulated with cellulose have an increased burn resistance. Studies show up to 50% more resistance than fiberglass. Fiberglass is a listed possible carcinogen and contains respirable glass fibers and formaldehyde. Conversely, cellulose insulation is considered a safe choice, and was the choice the American Lung Association of Virginia selected for their Breath Easy Office Complex.
Cellulose out performs fiberglass in sound control as well. A wall filled with fiberglass has a STC (Sound Transmission Class) rating of about 39 compared to cellulose at 44. That is the difference of having to ignore loud speech in an adjoining room or straining to hear it.
If you have concerns about our environment and like to choose ‘Green’ products put this in your pipe:
Cellulose insulation is 20% to 50% more effective than fiberglass. Using the 20% figure, if homes were insulated with cellulose instead of fiberglass there would be savings of 2.1 quadrillion BTU’s per year- the equivalent of a 51 day supply of gasoline for the entire U.S.
Fiberglass insulation has a recycled content of 0% to 35% whereas cellulose is 75% to 85%
The manufacturing emissions for cellulose is virtually zero, fiberglass creates over 1,200 pounds of carbon dioxide to generate enough insulation for just one home.
In conclusion, when you consider cost, energy savings, safety, health and environment concerns there really is only one choice.
Article provided by Ken Campbell of House to Home Interiors.