Use Less A/C and Cut Your Electric Bill
It doesn’t take much time or money to slash your cooling costs. Just follow these tips for energy savings.
Finding Air Leaks
Locating air leaks can be tricky. They’re often so small as to be hardly noticeable. To find them, follow a trail of smoke.
Close all the windows in the house, turn off all the fans and exhaust fans, and shut off the furnace. Light some incense and walk slowly around the outer walls of the house. Anywhere you notice the smoke blowing away from something or being sucked toward something, there’s probably an air leak. Now that you’ve found it, seal it! Here’s how.
Heat-Reducing Window Film
Heat control window film will help keep rooms cooler, and yes, you can install it yourself. These films reflect the sun’s heat and ultraviolet rays, and reduce glare without obscuring the view. The more direct sunlight coming through the window, the more the film will help (and it may lower your air-conditioning bills!). Applying the film takes approximately 30 minutes per window. It should last about 10 years. Prices vary with film size. A 3-ft. x 15-ft. film (which can cover two to three windows) costs about $30. The film is sold at home centers and hardware stores. Gila is one company that makes heat control film (gilafilms.com). Different types of film are available, so get the one designed for heat control. The film can be applied to any window, including double-pane low-e windows, although they already reduce radiant heat loss and gain. One drawback is that the film may void the manufacturer’s warranty for the seal on double-pane windows, although the film representatives we talked to said the film shouldn’t affect the seal. If the window warranty has already expired or reducing excessive heat is more important to you than possibly jeopardizing a warranty, then apply the film. Otherwise, consider other options, such as installing shades, awnings or shutters over the windows or even planting a tree to block the sun.
Cover Open Soffits
Builders often put a soffit where they want to put cabinets or recessed light fixtures, and sometimes they use soffits to contain heating ducts. Soffits have a high potential for leakage, especially if they contain recessed lights. Refer to your sketch and dig around in the insulation if necessary to find them. Reflective foil insulation, sometimes called ‘bubble-pack’ insulation, works well as an air barrier for soffits. It’s flexible and only about 1/4 in. thick, making it easy to cut with a scissors. You have to clear insulation from the surrounding wood to get the caulk to stick. Then cover the foil with insulation when you’re finished. However, don’t put insulation within 3 in. of recessed lights unless the fixture is IC rated (for ‘insulation contact’). The rating will be listed on a label inside the recessed can.
Get an Energy Audit
An energy audit entails a series of tests, including the blower door pressure test (shown), that tell you the efficiency of your heating and cooling system and the overall efficiency of your home. On the basis of the test results, the auditor will recommend low-cost improvements to save energy and larger upgrades that will pay you back within five to seven years. Audits take two to three hours and cost $250 to $400, but if you set one up through your utility company, you may be eligible for a rebate.
A basic part of an energy audit is the blower door test. The auditor closes all the doors and windows and then places a blower fan in a front or back door. This blower door test measures the ‘tightness,’ or air infiltration rate. The pressure and flow gauge shows the difference between the inside and the outside airflow so the auditor can calculate the air leakage rate.
Install a Programmable Thermostat
Setting your cooling system four to six degrees warmer when you’re away at work or on vacation and automatically lowering it to 78 degrees when you’re home can cut 5 to 20 percent off your energy bill. Mounting a programmable thermostat is a simple DIY project. Follow the manufacturer’s instructions for programming it.
Service Your Air Conditioner and Save up to $65 a Year
Roughly half of an average home’s annual energy bill (gas and electric), about $1,000, is spent on heating and cooling. Air conditioners placed in direct sunlight use up to 10 percent more electricity. If yours sits in the sun, plant tall shrubs or shade trees nearby—but don’t enclose the unit or impede the airflow. Place window units on the north side of the house or install an awning over them.
Keep your window or central air conditioner tuned up so it runs at peak efficiency (to do it yourself, see Cleaning Air Conditioners in the Spring). Every two or three years, call in a pro to check the electrical parts and the refrigerant (expect to pay $150).
If your central air conditioner is more than 12 years old, replacing it with an Energy Star model can cut your cooling costs by 30 percent and save maintenance costs. The payback for replacing a 12-year-old system is typically about eight years. An air conditioner’s efficiency level is measured by the seasonal energy efficiency ratio (SEER). The higher the number, the more efficient the unit. A 13 or 14 SEER rating is considered high efficiency.
Use a Leak Detector to Find Drafts
If your home is drafty, use a thermal leak detector (several brands are available online). The battery-operated handheld tool uses infrared sensors to identify spots that are warmer or colder than the surrounding area, signifying an air leak or poor insulation.
Just point the Thermal Leak Detector at windows, walls and ceilings. When the detector finds a cold or warm spot, the LED light changes from green to red (for warm) or blue (for cold).
Of course, you’ll still have to do some detective work to figure out what the problem actually is and how to fix it.
Clean or Change AC Filters Monthly
Dirty air filters are the No. 1 cause of air conditioning breakdowns and they cost about 7 percent more in energy costs (or about $45 a year) in hot climates. Change central AC furnace filters monthly during the summer. Most window units have a removable filter behind the air inlet grille that you can take out and rinse monthly.
Keep Cool With Shade
Cut AC costs through your own sweat equity by shading your house with trees, trellises and vines. Shading blocks direct sunlight through the roof and windows, which is responsible for about half of the heat gain in your home. Carefully positioned trees and horizontal trellises on the east and west sides can save up to 30 percent of a household’s energy consumption for heating and cooling. For an average household, that’s $100 to $250 in energy costs annually.
Photo provided by Heather Down istockphoto.
Use Fans and Raise Your Thermostat
Ceiling fans can save you money by keeping you comfortable at higher thermostat settings. Each degree higher than 78 degrees will save you 5 to 10 percent on air conditioning costs. The moving air from a ceiling fan increases the amount of evaporation from your skin and helps cool you off.
Photo provided by Hampton Bay