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The Rural Missouri NEWS Service
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February 2008 Insulation 101 What’s the fastest, most cost-effective way to save energy in your home? The answer, experts agree, is insulation. According to the U.S. Department of Energy (DOE), the typical U.S. family spends close to $1,500 annually on energy bills. DOE statistics show that, typically, 44 percent of a homeowner’s utility bill goes for heating and cooling and that 80 percent of older homes are under-insulated. DOE states you may be able to reduce your energy bill from 10 percent to 50 percent by taking certain steps. One of the major ones is increasing the amount of thermal insulation in your home — the equivalent of wrapping your house in a blanket to keep it cool in summer and warm in winter. How much will you save by insulating? The answer depends on factors like climate; size, shape and construction of your house; living habits; type and efficiency of your heating and cooling systems; and the fuel you use. In addition to saving money on your utility bill, increased insulation will add to the value of your home — an edge you may want to invest in if you plan to sell your house soon. How do you know if you need insulation? According to the U.S. Department of Energy – Energy Efficiency and Renewable Energy (EERE) and Energy Star, you need to insulate if you answer “yes” to these questions:
What’s an R-value? Heat naturally flows from warm to cool. In summer, heat flows in. In winter, heat flows out.
Insulation, which comes in many forms, resists the flow of heat. “R-value,” meaning resistance to heat flow, measures
insulation’s effectiveness. The greater the R-value, the greater the insulating power.
R-values are cumulative, so don’t remove old insulation unless it’s damp or mildewed. Adding a layer of R-19 insulation batt to an existing layer of R-19 batt will give you a total of R-38 — the minimum you need for an attic in Missouri. How much insulation do you need? Energy Star has a table at www.energystar.gov under Home Improvement and Air/Insulate that shows the R-value levels for insulation for all states. In Missouri, that ranges from R-38 to R-49 for ceilings, R-11 to R-26 for wood-frame walls, R-13 to R-25 for floors and R-11 to R-19 for basement/crawl space walls, depending on the type of heating system you have. R-38 is typically 12 to 15 inches of insulation. The Federal Trade Commission enforces R-values, which must be provided by the manufacturer, retailer or installer of the insulation you buy. Complaints may be made to 1-877-FTC-HELP (382-4357). You can calculate how much insulation you need for your specific home by using the U.S. Department of Energy’s (DOE) ZIP Code tool to calculate the R-value of existing insulation and determine how much more you need. Start with your ZIP, then answer questions about what type of house you have, its primary heating and cooling systems and where you want to check the insulation levels. The resulting report will tell you how much R-value to add and where you have enough. The site is at http://www.ornl.gov/~roofs/Zip/ZipHome.html or order the information on a CD-ROM from Oak Ridge National Laboratory, Oak Ridge, TN 37831-6070, fax 865-574-9354. Before you insulate Insulation alone will not stop all the leaks in your house. Caulk, weatherstrip and seal before you install insulation. Covering the leaks with insulation will make it more difficult to reach them later to fix. Here’s a useful list from the Missouri Department of Natural Resources on what to fix before you insulate:
A word about metal-framed buildings According to DOE more heat flows through metal studs and joists than through wood. Accordingly, placing insulation between the wall studs or between attic or floor joists doesn’t work as well for metal-framed houses as for wood-framed houses. DOE advises you to place continuous insulative sheathing over the outside of the wall frame, between the metal framing pieces and your exterior siding. If your attic has metal joists, you may want to place rigid foam insulation between the joists and the ceiling drywall. Types of insulation Insulation comes in many forms. The University of Missouri Extension Web site — http://extension.missouri.edu/explore/aggruides/agengin/g01721.htm — compares the R-values of different materials. Other materials that are not insulation per se but have R-values include brick, plywood, fir or pine boards, gypsum or plaster board, fiber board, carpet, concrete blocks, siding, air space and windows. The most common types of insulation, according to DOE, are: Fiberglass batts or rolls are made from mineral fibers and glass and available in widths suited to standard spacings of wall studs and attic or floor joists. Fiberglass blown-in loose-fill includes loose fibers or fiber pellets that are blown into building cavities or attics. According to The Attic Experts in Chicago, blown-in insulation retains its insulating value longer than batt. Cellulose insulation is typically made of paper waste treated with fire-retardant chemicals. One advantage is that it can be more densely packed or sprayed around pipes, wires and electrical boxes. Rigid foam board – This insulation is made from fibrous materials or plastic foams and is pressed or extruded into board-like forms and molded pipe-coverings. Spray foam is a polyurethane foam applied by a professional applicator. It also can help reduce air leaks. Radiant barrier is a reflective surface used alone and facing an open space, such as in an attic. Radiant barriers are more effective in hot climates. Do it yourself or hire a professional? Installing insulation can be a do-it-yourself job depending on the design of your house, the materials used in its construction and your own experience and skills. If you do it yourself, DOE advises you to wear protective clothing and don’t pack insulation around bare stove pipes, electrical fixtures, motors or any heat-producing equipment. If yours is an old house, have an electrician check to see if the electrical insulation on your wiring is degraded or the wires overloaded. The DOE’s site at http://www.ornl.gov/sci/roofs+walls/insulation/ins_12.html provides helpful guidance on installing batts, rolls, rigid board, loose-fill and reflective insulation. Installing insulation in the attic floor can be relatively easy but more difficult in exterior wall cavities. Insulating basement or crawl space walls or floors can be done by homeowners using rigid or batt insulation. Most spray applications require contractors. If you hire a professional, DOE recommends getting bids from several contractors for the same R-value. You may find the quoted prices for a given R-value installation vary by more than a factor of two. Measure the depth of insulation installed to make sure you’re getting what you paid for. And be sure to get a signed and dated statement describing the insulation installed. You can locate a member of the Insulation Contractors Association (ICA) to install insulation at http://www.insulate.org/locate.html. In Missouri, the following are ICA contractors:
Alladin Insulation/Masco Eastern Division
Gale Insulation/Masco
Hayes Insulation Co.
Ozark’s Modern Insulation
Where to insulate Regardless of what insulation material you use, here are useful tips from Energy Star, the University of Missouri Extension and www.consumerenergycenter.org on where to insulate:
In summary, here’s an at-a-glance list of where to insulate from DNR:
An insulation word to the wise Two frequent insulation problems are poor workmanship and moisture condensation. Neil Meador with the Missouri Department of Agricultural Engineering points out that you’ll pay for the decreased effectiveness of improperly cut and fitted insulation as long as you own the house. During winter, moisture is added continually to the warm air inside your house, creating water vapor. When water vapor encounters a cold surface, such as inside an insulated wall, it condenses to a liquid, causing the insulation to become wet. Using a vapor barrier will stop water vapor from entering the wall or ceiling and condensing on cold surfaces. Useful Web sites for insulation info... DOE and its EERE office have a comprehensive “Insulation Fact Sheet” at http://www.ornl.gov/sci/roofs+walls/insulation/ins_02.html. DOE’s site at http://www1.eere.energy.gov/consumer/tips/insulation.html#map includes a map of recommended R-values. North American Insulation Manufacturers Association at http://www.naima.org/. Cellulose Insulation Manufacturers Association at http://www.cellulose.org/. Spray Polyurethane Foam Alliance at http://www.sprayfoam.com/cdps/cditem.cfm?nid=3. |
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