OK. It's officially summer here in Washington, D.C. I'm seeking the coolest, shadiest places possible as I get ready for the hottest few months of the year. It's already been a hot June in much of the country, and it may end up being one of the hottest Junes on record in DC.
Naturally, I'm starting to think about how I'm going to stay cool this summer, while trying to minimize my energy use. Drew provided some excellent tips on summertime energy savings in his blog post two weeks ago, and Allison examined the potential of using strategic shading to help keep your house cool in her blog post on May 10. Our readers also supplied some great comments on keeping your house shaded with plants when we asked later that week how you shade your home in the summer.
Some of my favorite take-aways from those post were: plant well-placed trees to save up to 25% on your energy costs and cool the surrounding air temperatures by as much as 9°F—which also helps remove some carbon from the atmosphere; position small groundcover plants to reduce radiant heating from the ground near the house; install awnings and overhangs to keep sunlight off windows, and keep your blinds and curtains closed during the day; and always ensure proper ventilation when using shade barriers keep walls cool.
I thought I'd look a little closer at air conditioners—since that's one of the biggest energy users in homes across much of the country. Air conditioners use about 5% of all the electricity produced in the United States (wow!), at a cost of over $11 billion to homeowners. As a result, about 100 million tons of carbon dioxide are released into the air each year—an average of about two tons for each home with an air conditioner.
By switching to high-efficiency air conditioners and taking other actions to keep your home cool, you could reduce your energy use by 20% to 50%. If you're considering buying a central air conditioning unit, you can get a 30% tax break until the end of the year if you buy a qualified energy-efficient model. In some states, you may still be able to get a rebate on an ENERGY STAR air conditioner purchase through a Recovery Act-funded program.
Properly maintaining your air conditioner is key to keeping it running efficiently. The most important thing is to routinely replace or clean its filters. Keeping the filter clean can lower your A/C unit's energy consumption by 5% to 15%.
Also, check your evaporator coil every year and clean it if necessary. For outdoor A/C units, condenser coils can also become very dirty if the outdoor environment is dusty or if there is foliage nearby. Cleaning the area around the coil, removing any debris, and trimming foliage back at least two feet gives adequate air flow around the condenser. Also, shading the outside unit can increase its efficiency by up to 10%! How cool is that?
For window units, inspect the seal between the air conditioner and the window frame to ensure it makes contact with the unit's metal case. Moisture can damage this seal, allowing cool air to escape from your house. When your A/C unit needs more than the regular maintenance routine, hire a professional service technician to tick off the items on your A/C maintenance checklist.
Another good way to save money on your cooling bill is to improve airflow in your home through various ventilation strategies, since fans use far less energy than A/C units. Adding a window fan or ceiling fan to your bedroom or installing an attic fan can reduce or eliminate the need to run an air conditioner at night. Ventilated attics are about 30°F cooler than unventilated ones. Properly sized and placed louvers and roof vents help prevent moisture buildup and overheating in your attic.
Have a great summer—keep saving energy and cutting emissions—and be cool!