Before you make an energy-saving investment — a few bucks for caulking or thousands for a new furnace — it pays to know how your household consumes it. After all, why add more insulation in the attic where the last inch costs as much as the first if there's only a marginal improvement in fuel savings?
The best returns come in two areas: weak links, for example, a pull-down attic stair that has no insulation blanket, and the biggest users, space heating and cooling. An HVAC engineer could provide an analysis. Most local utility companies will conduct an energy audit at low or no cost. Some HVAC contractors have infrared scanners that can pinpoint energy leaks.
On-site audits help because every household is different, and some use a lot more energy than others. But your costs are probably distributed according to this rundown of national usage by the Department of Energy. Taking into account all fuels sources, almost half of the budget, 45 percent, goes for conditioning living spaces — 32 percent for space heating and 13 percent for cooling. No other category comes close. The next largest is water heating at 15 percent. Working down the list, lighting accounts for 10 percent, refrigeration 8 percent, electronics (televisions and other appliances) 7 percent, cooking 5 percent, wet cleaning (clothes washers and dryers, and dishwashers) 4 percent, and computers 2 percent. All other categories are marginal and not broken out individually by the DOE.
Your best chance of a good return can be found in projects that save on heating and cooling. For example, if you upgrade to a new fan and a programmable thermostat that reduce the bill by 10 percent, you'll save about 5 percent of overall energy use. With fuel costs rising, a modest efficiency increase in heating and cooling will probably meet the rule of thumb that an energy-saving investment should pay for itself within 7 years.
On the other hand, if you spend a lot to change from incandescents to LED or compact fluorescent (CFL) light bulbs, the savings in energy consumption will affect only 10 percent of the energy bill. The incandescent light bulb phase-out may or may not take effect in 2012 as scheduled. But even the possibility of passage has caused runs on standard bulbs in many stores. Home Depot, for one, reports a double-digit increase in the sales of incandescents as well as a spike in LED sales.
Three factors drive the incandescent buying surge. First, many people want a bright light like a 150-watt incandescent for reading or close work. Second, CFLs cost a lot more, according to the DOE, about six times the equivalent incandescent, though the trade-off is that CFLs last longer and use less energy. Third is the clincher for many consumers, the elaborate disposal methods when CFLs wear out or break. They stem from concern about mercury sealed inside that can escape as mercury vapor. The Environmental Protection Agency has posted a 1,300-word set of clean-up instructions. They include: open a window and leave the room for 5 to 10 minutes; shut off the forced hot-air or air conditioning system for several hours. And after you clean up the pieces and vacuum, the EPA says you should clean up what you used to clean up. "Remove the vacuum bag (or empty and wipe the canister) and seal the bag/vacuum debris, and any materials used to clean the vacuum, in a plastic bag. And for all the trouble, by law or by choice, switching bulb types affects only a percentage of one of the smallest pieces of the residential energy pie, the 10 percent for lighting.
To find out more about energy use in your home, also consider some of the interactive websites that basically conduct an online energy audit. For example, energystar.gov offers a program called the Home Energy Yardstick. On the Lawrence Berkeley National Laboratory site called Home Energy Saver (hes.lbl.gov/consumer), the program crunches information you provide about utility costs, home square footage and other parameters, and in a few minutes comes up with comparisons to typical homes and how much different energy-saving investments will pay off in your situation.
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