Ultimate Guide to Home Energy Audits

If you're looking for ways to redraw your home energy consumption, you might consider a home energy audit to pinpoint problem areas. See more pictures of green living.
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With oil prices skyrocketing, and concerns over the environment at an all-time high, it's no wonder that people want to conserve energy. Making your home more energy efficient will not only reduce its carbon footprint but could also save you a lot of money -- shaving as much as 30 percent or more off your energy bills [source: DIY Network].

You think of your house or apartment as a solid foundation surrounded by sturdy walls. Though it can protect you from the elements, your home is not an impenetrable barrier. Cracks and crevices in windows, doors, walls, chimneys and pipes can create drafts, which force your heating and cooling system to work overtime. Insulation acts like a sweater to keep the heat inside your home, but if that sweater isn't thick enough (which is a problem especially in older homes), it won't do much to keep your home warm. And appliances can be real energy drainers if they're old or overworked.


Doing a home energy audit is an easy way to see how much energy your house is using --and losing -- every day. It can help you spot problems and take the right steps to improve your home's efficiency. Depending on your goals and budget, you can either do the audit yourself or pay a professional to do it for you.

So let's say you're ready to audit your home. Where do you start? In the next section, we'll find out.


Do-It-Yourself Home Energy Audits

Start any home energy audit by looking over your old energy bills.
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Before starting a home energy audit yourself, it's helpful to know what you're dealing with. Gather your energy bills from the last couple of years and compare them month-by-month to look for trends. Spikes in energy usage during specific times of the year can offer clues about your consumption.

Here's what to do.


Find the air leaks: Walk around your house and feel for air leaks in these places:

  • Gaps in the baseboard and where the walls and ceiling meet
  • Window and door frames, as well as their weather stripping and caulking
  • Mail slots and doggie doors
  • Fireplace dampers
  • Window-mounted air conditioners
  • Electrical outlets and switch plates
  • Pipes
  • Areas where building materials come together (such as in corners, around chimneys and along the foundation of your home)

If you're having trouble finding leaks, close any doors, windows and fireplace flues. Turn off combustion appliances, such as the water heater and furnace. Then turn on exhaust fans to pull air from the outside and make leaks more obvious. Either wet your hand and wave it in front of suspected areas (the draft should feel cool on your hand) or use the smoke from a stick of incense to see where the air moves.

Investigate the insulation:Check the thickness of your attic insulation to make sure it meets current recommendations. There also should be a vapor barrier under the insulation. The insulation should cover holes in ductwork, pipes and chimneys.

Once you've finished in the attic, head downstairs and check the basement. Unheated basements should also have insulation under the floor of the living area. Heated basements should have it in the foundation walls, as well as around the water heater, hot water pipes and furnace ducts.

Also check crawl spaces, ceilings and outside walls to make sure they're well insulated. To know whether there's insulation in your walls, turn off circuit breakers so that the electricity is off, remove the cover plate from the outlet and push a long, thin wooden stick into the wall (or drill a hole into the back of a closet). If you meet resistance, it means there's some insulation.

Check out heating and cooling equipment: Your furnace and air conditioner can be big drains on your home energy use. If your units are more than 15 years old, consider replacing them with more energy-efficient systems.

Have your heating and cooling systems checked by a professional each year. Replace the furnace filters as often as the manufacturer recommends (usually about once every month or two, especially during the winter when it's running regularly). If you have central air, vacuum the coils if they're dirty.

Look into the lighting: Using the wrong type of lighting can put a strain on your energy bill. If you have 100 watt bulbs, you may be able to get away with 60 or 75 watts. Or switch to compact fluorescent lightbulbs (CFLs), which use about 75 percent less energy than standard bulbs. Using more energy-efficient lighting may even get you a rebate from your utility company. You can also save energy by installing dimmer switches and sensors that flip off lights when no one is around.

Hunt for energy losers: Refrigerators, dishwashers and other appliances can sap energy if they're not properly set up and maintained. To see how much energy your appliances are using, plug in a Kill-A-Watt Electric Usage Monitor, which will give you details on energy use and show you how much extra you're spending. You may be able to make slight adjustments -- for example, adjusting the temperature on your refrigerator -- to improve your numbers. Also unplug any appliances (like DVD players or computers) when they're not in use.


Professional Home Energy Audits

The test attaches a fan to the outside door. The fan pulls air out of the house to lower the inside air pressure. Air from the outside flows in through any openings. While the air is being pulled out, the auditor can see where the leaks are occurring.
HSW 2008

Don't have the time or patience to do your own energy audit? Consider hiring a professional energy auditor. The auditor will do a room-by-room check to make sure your home is operating efficiently. Although there is a cost involved, it's usually no more than $200, and your utility company may offer to pick up part or all of the tab. Plus, the money you'll save in the long run will more than make up for anything you spend on the audit.

Even if you hire a pro, though, you need to prepare. Get a list ready of any problems you suspect. Also have copies of your energy bill over the last 12 months (call your utility company for copies if you don't have them on hand), so the auditor knows where to be on the lookout for potential problems.


To find an energy auditor in your area, ask neighbors or friends for a recommendation, look in the Yellow Pages under "energy" or call your local government energy office or utility company. When choosing a contractor, make sure the person is licensed and insured. Ask for references and check them. Call the Better Business Bureau and find out if there have been any complaints made against the company.

During the audit, the contractor should use a calibrated blower door test to check how well your home is sealed off against outside drafts, and a thermographic inspection to detect leaks. A professional audit should also include a check of leaks in the duct system, and a test of the heating and air conditioning units.

Thermographic inspections use infrared cameras to identify where heat is escaping from your home. The heat shows up on the camera as white, yellow and red. Sometimes this test is done together with the calibrated blower door test.
HSW 2008

So the audit is done and you've identified your problems. What next?



After the Audit -- What Next?

Even before the era of energy audits, thrifty homeowners knew the value of caulk.
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­At the end of the audit -- if you've had it done for you -- the contractor should give you a list of recommendations for making your home more energy efficient. Some auditors will also tell you how much you can save if you switch out your current systems for more energy-efficient equipment. If you've done the audit yourself, you should have your own checklist of trouble spots that need addressing.

Either way, don't immediately run out and drop $20,000 on a new furnace or air conditioning unit. Before making major overhauls to your home, first try some quick fixes -- like adding insulation or caulking crevices. They may be enough to do the trick.


Here are some of the most common trouble spots, and how to fix them:

  • Seal all sources of air leaks and cracks, including holes and cracks in windows. For small leaks (under 0.25 inch, or 0.63 cm), caulk usually works best. Expanding foam usually works better for larger holes. If you have really big openings (such as attic hatch covers), fill them with insulation (rigid foam or fiberglass). Also fill in any gaps in the insulation lining your attic, basement, crawl spaces and walls.
  • Add weather stripping to the tops, sides and bottom of doors, as well as around window sashes. Repair or replace any windows that are damaged or cracked. If they're in really bad shape, consider investing in newer, energy-efficient windows. You may get an added bonus by replacing your windows in the form of a tax break. Consider adding storm windows and thick blinds or curtains, which are good for preventing heat and cold loss.
  • Replace high energy lightbulbs with lower wattage or compact fluorescent lightbulbs, especially in the lamps you use most often, such as in your den and office.
  • When buying new appliances (and if your appliances are more than 10 years old, it may be time to start thinking about it), look for the Energy Star label. These products use 10 to 50 percent less energy than regular appliances [source: Energy Star]. You can also make the appliances you already have more efficient. For example, regularly vacuum your refrigerator coils and air conditioning unit, because getting the dust off will help them work better.

If you do need to make major improvements, you can hire a professional to help. There are companies that can help you pay for the improvements, such as Clean Power Finance.

To learn more about home energy audits and other related topics, check out the links on the following page.


Lots More Information

Related HowStuffWorks Articles
More Great Links


  • "Home Energy Audit and Thermographic Inspection." DIY Network. http://www.diynetwork.com/diy/he_diagnostics/article/0,,DIY_13893_2274796,00.html.
  • Le, Anh-Minh. "Audit Home for Energy Efficiency." SFGate.com, April 19, 2008. http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2008/04/19/HO8DVVR70.DTL.
  • The Daily Green. "DIY Home Energy Audit."http://www.thedailygreen.com/green-homes/latest/DIY-home-energy-audit.
  • Seattle Department of Planning and Development. "Do-it-Yourself Home Energy Audit." http://www.seattle.gov/light/printdocs/DoItYourselfHome.PDF.
  • U.S. Department of Energy. "Your Home's Energy Use." http://www1.eere.energy.gov/consumer/tips/home_energy.html.
  • U.S. Department of Energy. "Home Energy Audits." http://www.eere.energy.gov/consumer/your_home/energy_audits/index.cfm/mytopic=11160.