The Dirty Details
If you’re looking to reduce your carbon footprint, start at home. Saving energy can be as simple as turning off lights, electronics and appliances when you’re not using them, and adjusting your thermostat—and you’ll see the savings add up on your energy bills.
More than half of the energy used in the average home is for heating and cooling. Air leaks in your walls, windows or ductwork will drive up your energy use. Substantial energy losses can also occur if there’s inadequate insulation in walls and ceilings. If you live in an older home, in particular, you could be losing up to 30 percent of the energy you pay for.
Keep the following parts of your home in mind when working to cut down energy use:
Lighting comprises 5 to 10 percent of your energy bill. Changing light bulbs is a small investment, but over time it can save significant amounts of energy and money. Replace inefficient incandescent bulbs, which can lose up to 90 percent of energy as heat, with LEDs or compact fluorescent bulbs.
Weather stripping and caulk are inexpensive and can be used to seal air leaks that cause drafts. Leaky ductwork can reduce efficiency of your system by 15 percent. Check areas around door and window frames, electrical outlets, light switch plates, baseboards, vents, pipes and wires for gaps and cracks. Have a professional auditor inspect your system once a year—they will use special tools to detect air leaks that go beyond visual inspection.
Many older homes lack adequate insulation in walls. Before building codes were updated, homes in California used to use as much energy for heating as those in Minnesota. Despite building code changes, attics may still be poorly insulated in newer homes.
Adding insulation may be a larger investment for exterior walls, but additions to an attic are generally less expensive and easier to do. Overall, upgrading insulation can significantly reduce energy use—you could save up to 20 percent on your heating bill. The Home Energy Saver tool can help you calculate how much insulation is recommended in your zip code and type of house.
Drafty windows can account for to 10 to 25 percent of overall heat loss. Weather stripping and insulating around windows can help reduce energy losses, but if you have older, single-pane windows you may want to consider replacing them.
Window frames and glazing also can also affect energy loss. Wood frames are a better choice than aluminum frames, which can have condensation problems, or vinyl and fiberglass, which have more environmental impacts from production. If you choose aluminum frames, they should have insulating strips between the inside and outside of the frames.
Here are our tips for selecting windows:
- Adding storm windows may reduce heat loss from a window by 10 to 20 percent without requiring the purchase of new windows.
- Look for Energy Star-labeled windows that have at least double-panes and low-E, or low-emissivity, coatings to reduce heat transfer through the glass. Windows with low-E coatings may cost 10 to 15 percent more, but can cut energy losses by 30 to 50 percent.
- Choose windows with a low U-factor (at least 0.4 or lower) for maximum efficiency in cold climates. U-factor or U-value indicates how well the whole window insulates. A lower U-factor indicates less heat loss.
- In colder climates, south-facing windows with a low U-factor and a high Solar Heat Gain Coefficient, or SHGC, (0.6 or greater) will maximize heat gain in the winter. SHGC measures how much heat is gained from the sun through the window. In the summer, south-facing windows don’t add significant heat when properly shaded.
- Choose low SHGC (0.4 or less) windows in warm climates to keep heat out. Make sure the glazing has at least 0.6 Visible Light Transmittance, or VT, to maintain lighting. VT is the fraction of light that passes through the window, and a higher number maximizes daylight.
- In warmer climates, it is difficult to control heat from east- and west-facing windows. But there is not much heat gain from north-facing windows, so they are not worth the additional expense of low SHGC windows.
- Check with your local utility if there is a rebate program in your area for upgrading windows.
- To calculate how different materials and types of windows can help you save energy, use this free software developed by the Lawrence Berkeley National Laboratory: windows.lbl.gov.
Consider upgrading old, inefficient appliances. While the upfront costs may seem high, it should save you money in the long term. Use the Energy Star product finder to determine if you should invest in newer models. Below are the top three most energy-intensive home appliances:
- Water heaters. The average American spends over $200 a year to heat water. If you typically use less than 40 gallons of hot water per day, consider a tankless water heater. These can be 20 to 30 percent more efficient than conventional storage tank water heaters. Tankless water heaters may cost more upfront, but they can last twice as long as their conventional counterparts.
- Clothing driers. If your dryer is outdated, consider replacing it with an Energy Star-rated model. Try to use your dryer less by hanging clothes outside to dry or washing your jeans less often.
- Refrigerators. Energy Star-rated refrigerators are about 10 percent more efficient than standard models.