When it comes to greening a house, especially older homes, nothing is more cost-effective than investing in a little extra ‘fluff’ inside the walls and in the attic.
Back in September 2012, the U.S. Department of Energy (DOE) celebrated a barely acknowledged milestone in the nation’s drive towards a sustainable future – over 1 million homes weatherized. The intent of the DOE’s Weatherization Assistance Program (WAP) is to greatly reduce the crippling cost of heating and cooling for low-income families through a mix of energy-efficient retrofits, and yes, better insulation. While heating and cooling costs may not be a crippling drain for middle-class Americans, they are a drain nonetheless – comprising nearly half of a home’s total energy bill. To put that in dollar terms, the Department of Energy estimates that homeowners will spend about $1,000 a year on heating when it’s cold outside, and cooling when it’s just too darn hot. We may thank God we live in an age of ubiquitous air conditioning, but it sure is eating a hole in our pockets. Dollar for dollar, investing in insulation is the best thing you can do when it comes to reducing energy consumption and costs.
What To Do?
Step 1 – Determine your R-value.
Get a whole-house energy assessment in order to determine your home’s R-value, or how effectively the house stays cool during the summer and retains heat during the winter. For the do-it-yourself types, that means taking a look at the insulation behind electrical outlets or beneath the floors in unconditioned spaces (i.e. above the garage). For fiberglass batting (pink fluff), multiply the depth by 3.2 to get a rough R-value estimate. For cellulose (flat grey fibers), multiply by 3.7, and for open cell spray foam insulation, multiply by 3.8.
The recommended R-value of walls is ultimately determined by local climate and cost considerations. Energy Star recommends an R-value of R30-R60 for attics and walls, and R13-R19 for floors of homes located in “climate zone 2”, which encompasses Central Texas. However, the more insulation, the better your home’s energy efficiency performance. It really is that simple.
Step 2 – Determine where you need to insulate and also find leaks.
Once you’ve determined the R-value of existing insulation, and a target insulation R-value, it’s time to figure out where you need to insulate. Insulation is all about separating the inside from the outside and creating a comfortable microcosm for living. Key areas to consider insulating include the floors, exterior walls, walls adjacent to unconditioned spaces (i.e. the garage), and the attic. Properly insulating the attic is probably the easiest way to cut energy consumption. During the winter, interior heat rises and escapes through the attic comprising nearly 45 percent of the heat lost. During the summer, sunbaked roofs tend to radiate heat back into the attic and spaces below.
Unfortunately insulation alone is no guarantee of energy efficiency. Nothing kills aspirations for energy efficiency faster than air leaks. Ensure that all leaks are identified and plugged – that means sealing attic floors, proper caulking, and weatherstrips for doors. In the same vein, uninsulated or poorly fitted ductwork is a major concern – potentially cutting efficiency by 40 percent and effectively mitigating any gains from added insulation. In other words, check your ductwork!
Step 3 – Choose your insulation type.
Most homes are stuffed with traditional fiberglass batting (pink fluff) which is cheap and does not require any specialized tools to install. Unfortunately, traditional batting has lower R-values than comparable amounts of cellulose, mineral wool, foam board, or spray foam insulation.
When it comes to bang for your buck, spray foam insulation tops the list. Unlike traditional blown or rolled fiberglass or cellulose, spray foam can reach all the little cracks and crevices – resulting in a high R-value and eliminating air infiltration. In a typical new construction or existing home retrofit scenario, it is applied to the underside of the roof deck vs on top of the ceiling, so it is preventing hot and cold from ever entering the attic space. It cannot be overstated how important it is to obtain R-value, air sealing, and block hot and cold from ever entering the attic space where the ductwork resides – all from the same product application.
Buildings insulated with spray foam insulation routinely perform 30 to 50 percent better than comparable buildings with fiberglass batting. To top it off, homes insualted with spray foam often qualify for state and federal tax deductions.
Step 3 – Save money from day one.
The great thing about investing in insulation is that you start seeing immediate results in thermal comfort and on your monthly bills. Payback times range from under a year to several years depending on the R-values, insulation material chosen, and geographic location. When insulation is pursued as a part of an overarching green strategy, such as found in net-zero houses, the results can be astounding. For example, if done at the time of new construction or when the heating and air conditioning equipment is due for replacement on an existing home, a spray foam roof can usually reduce the heating and cooling loads to allow a reduction in sizing of the new HVAC equipment. Ultimately, insulation is only a component, albeit a key component, of a holistic approach that will change the way we build, and the way we live.
If there was a surefire way to pay $1 now and get $2 tomorrow, we would all do it. When it comes to retrofitting an existing home for energy efficiency, insulation should be a key consideration. With fast payback times and an attractive cost-benefit ratio, there’s really no reason not to invest in some extra “fluff” for your home.
Live Well. Think Green. BuildNative.
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