Home Insulation

Adding or updating your home's insulation is one of the smartest investments you can make. It envelops your home keeping it warmer in the winter, lowering your heating costs, and cooler in the summer, easing the load on your cooling system. It absorbs sound, reducing unwanted noise from appliances and audio equipment transmitted through your walls and floors. And it promotes better air quality and a healthier environment by sealing air leaks and controlling moisture - important when mold and mildew are of concern. Determing the best type of insulation to install can be a little confusing, but don't let that deter you. Do some homework and learn what an "R-Value" is (the insulation's resistance to heat flow; the higher the R-Value, the greater the insulating) and then read labels. The Federal Trade Commission (FTC) has clear rules about what should be stated on residential insulation labels. Once you figure out what areas of your home need to be insulated, you can make an educated decision regarding the appropriate insulation to use. Inadequate insulation and air leaks are some of the leading causes of energy waste. When corrected, the amount of energy and money saved depends on where you live, the size and construction of your home, your family' habits, and the fuel and efficiency of your home's heating and cooling systems. The Basics of Insulation Heat flows naturally from a warmer space to a cooler space, which means in winter, heat moves from the warm indoors to the cold outdoors and, in the summer, heat moves from hot outdoors into the cool indoors. This heat exchange means more work for your heating and cooling system, which means more energy and money spent. Insulation decreases this heat exchange by providing an effective resistance to heat's movement. Batts, blankets, loose-fill, and low-density foams all work by limiting air flow. Reflective insulation works by reducing the amount of energy traveling in the form of radiation. A quick primer on the different types of insulation (R-Values vary for each):

• Rolled or Batt Insulation - fiberglass in "blankets" designed to be installed in between wall studs, floor joists, or ceiling rafters.
• Rigid Insulation - board-like forms and/or molded pipe-coverings filled with packed air cells good for insulating foundation and basement walls.
• Blown-In Fiberglass Insulation - loose fibers blown into place; good for irregularly-shaped areas or unfinished attic floors.
• Foam Insulation - polyurethane foam sprayed into place; typically in new home construction.
• Reflective Insulation - constructed out of aluminum foil and placed between floor joists, rafters, and wall studs; works by reflecting radiant heat back into a home.

Costs of Insulation and Installation There are several variables that impact the total cost of installing insulation, including desired R-values, local climate, size of space, and type of insulation. Estimates, done by CostHelper.com, for having a professional "insulate an open attic to modern standards is $0.50 - $2.25 a square foot depending on local climate and the desired R-value of the materials. Do-it-yourself materials for roll-out batting in an open attic can run $100 - $500, depending on R-values, attic size and other factors." Another estmate for a professional "to blow insulation into a flat roof, cathedral ceiling or wall cavities is $2.00 - $3.50 a square foot, or $1,000 - $3,500 for filling 1,000 square feet of empty wall or roof space." Check with your utility company to see if they offer rebates and programs that encourage homeowners to install effective insulation. Oak Ridge National Laboratory's Zip-Code Insulation Program is a tool that provides insulation levels for a new or existing home based on a zip code and other basic information about your home. Where to Insulate Insulation should be installed anywhere between a heated and an unheated space. For the best in energy efficiency, that includes:

• Attics - an uninsulated attic can increase energy bills by 30%.
• Ducts - in attics, crawl spaces, garages, or basements.
• Cathedral ceilings
• Exterior walls - installing insulation in a new home is an easy task; however, installing it in an older home can be a difficult and expensive endeavour.
• Floors above unheated garages.
• Basements
• Crawl spaces - uninsulated crawlspaces can increase energy bills as much as 15%.
• Slab-on-grade floors

This Old House has a great visual and matrix regarding where you should insulate. Understanding R-Value Insulation is rated in thermal resistance, called the R-value. R-value indicates the resistance to heat flow; the higher the R-value, the greater the insulating effectiveness. The R-value of insulation depends on the type of material, its thickness, and density. Recommended minimum R-values for homes vary by climate, home construction, and type of heating system used.

• For temperate climates: R-11 in walls and floors, R-19 in ceilings below ventilated attics.
• For moderate climates: R-19 in walls and floors, R-30 in ceilings below ventilated attics.
• For cold climates: R-19 in walls and floors, R-38 to R-49 in ceilings below ventilated attics.

For more specific recommendations by region, visit the Department of Energy. More on understanding what R-value is and if your home needs more of it from This Old House. General Installation Considerations Before beginning any installation work, follow these safety and fire precautions from This Old House:

• Read the label and follow all the manufacturer's directions.
• Wear clothing adequate to protect against skin contact and irritation; a long-sleeved shirt with collar and cuffs buttoned, gloves, hat, glasses, and disposable dust respirator are advisable in all do-it-yourself insulation projects.
• Do not cover or hand-pack insulation around bare stove pipes, electrical fixtures, motors, or any heat-producing equipment such as recessed lighting fixtures; electrical fire-safety codes prohibit the installation of thermal insulation within 3" of a recessed fixture enclosure, wiring compartment, or ballast, or above the fixture so that it will trap heat and prevent free circulation of air, unless the fixture is identified by label as suitable for insulation to be in direct contact with the fixture.
• If your home is very old, have an electrician check to see if the electrical insulation on your wiring is degraded or if the wires are overloaded; in either of these situations, it may be hazardous to add thermal insulation within a closed cavity around the wires because it could cause the wires to overheat.
• If your home was wired using the now obsolete method called knob and tube wiring, the National Electric Code forbids the installation of loose, rolled, or foam-in-place insulation if the insulation would surround the wires and prevent heat dissipation from the electrical conductors to a free air space.
• Do not cover attic vents with insulation; proper ventilation, especially in attics, must be maintained to avoid overheating and moisture build-up.