4 insulation types to keep your home comfy
Anne Lundgren | Improvement Center Columnist | July 23, 2013
Keeping your house at a comfortable temperature throughout the year is important, and using the right type of insulation can help regulate heating and cooling as well as save you money on your energy bill.
Experts rate insulation's effectiveness using a numeric scale that indicates thermal resistance known as R-value. They calculate R-value by dividing the measure of the insulation's thickness by the thermal conductivity of the material. Simply put, the higher the R-value number, the less your insulation lets warm air escape during cold months and hot air indoors when your thermometer spikes 110 degrees. The primary goal of insulation is to stop the movement of heat, whether it's from the outside-in or the inside-out.
Of course, R-values are primarily calculated in laboratories. You need to also take into account factors such as humidity, extreme temperatures, wind and changing conditions throughout the year. (For example, the longer the days, the more the sun beats down on your roof and the hotter your house can get.) Initial cost can also complicate your decision. Here are four of the most popular types of insulation materials available in today's market and what you might want to consider about each:
Fiberglass blanket insulation
You can find this type of insulation readily available at your local big box home improvement center. Installation is relatively easy, though you should wear protective gloves, long sleeves and pants, and a mask to avoid inhaling the particles--fiberglass is made up of melted and spun sand and glass. Blanket insulation comes in rolls or pre-cut batt in standard sizes.
Price and availability make this a popular choice; however, it is a low-density material and wind can push heat through blanket insulation rendering it less than optimal, particularly in extremely cold and hot climates. Also keep in mind, doubling up your blanket insulation doesn't mean doubling effectiveness. If you squash the batt in a tight space, you compromise its efficiency.
Probably the most common type of insulation, fiberglass batt insulation typically has an R-value range from R-13 to R-30 and costs from $0.20 to $0.40 per square foot for R-13 to $0.60 to $1.00 per square foot on the R-30 end of the scale.
Loose-fill (blown-in) fiberglass or cellulose insulation
Professionals are typically necessary to install this type of insulation -- "blown in via pneumatic" means that installers use a blowing machine. Consider this type of insulation for areas such as attics and inside walls or enclosed attic floors. Fiberglass and cellulose insulation have the same R-value; however, cellulose insulation tends to be 2 to 3 inches thinner. Composed of recycled newspaper with chemical additives to reduce flammability, cellulose insulation competes well with more traditional fiberglass. In addition, the flame-retardant additives make it less of a fire hazard than fiberglass insulation, which must be kept away from light fixtures, exhaust flues and active chimneys.
The R-value tends to be higher for loose-fill fiberglass, ranging from R-30 to R-50 and costing from $0.45 to $2.25 per square foot. New homes benefit the most from blown-in insulation because it can be installed at framing. Installation tends to be more difficult in existing homes.
Available as fiberglass or mineral (rock or slag) wool, this insulation can be best used in areas of the home needing to withstand high temperatures. Consider it for specialty areas of your home where you need to avoid fire mishaps. Homeowners can benefit from this type of installation in existing crawl spaces and attics.
Rigid insulation ranges in price from $0.20 to $0.70 and has a lower R-value at 3.8 to 6.5, so it is a more job-specific product than fiberglass batt or blown-in insulation. Professional contractors install and fabricate rigid insulation in their shops or at job sites. This is not a product for the typical DIY weekender.
This type of insulation method consists of foil-faced kraft paper, polyethylene bubbles, plastic film or cardboard. The material is fitted between wood-frame studs, joists, rafters and beams, and is best for unfinished floors, walls and ceilings.
Reflective insulation has been found to be the most effective for reducing downward heat flow. Unfortunately, reflective insulation systems aren't easily measured by R-values as the heat is reflected rather than absorbed. Considered a radiant barrier, this insulation system works best for roofs. Just remember to minimize dust accumulation to keep the reflective surface optimally functioning. The Home Depot price for reflective insulation is $43.25 for a 4-by-25-foot roll.