Though it may cost a little up front, a home energy audit could reduce your utility costs by 30 percent. Think of it as a checkup for your home's energy system (both heating and cooling): its consumption, structure and operating practices. An effective energy audit will teach you as much about your energy-use habits as it does about the house's construction and systems. Increasing your awareness and improving your habits is often the biggest source of future savings.
Providers and costs
A variety of providers offer home energy audits. Utility companies are the most common source and often subsidize most of the audit's cost. You can also request audits from companies that manufacture or install building components and appliances that affect a home's energy efficiency.
No matter who performs the audit, you should always take into account the provider's motives — that is, what product the firm sells. For example, if a window company performs an audit and then recommends new windows, you may want to seek an unbiased second opinion.
Another factor to keep in mind is that not all audits evaluate all aspects of energy use equally. For example, an audit performed by a natural gas company may focus primarily on gas use, though its report will likely include information and tips for also improving electrical energy efficiency.
A basic energy audit typically costs $25 to $100 and includes a visual inspection and evaluation of the building envelope, HVAC equipment, appliances and windows and doors. The provider produces a report that includes basic improvement recommendations.
An advanced energy audit typically will cost $100 to more than $500, depending on the services offered and whether part of the cost is subsidized. In addition to the services provided in a basic energy audit, an advanced audit usually includes more comprehensive report and diagnostic tests (see photos below), such as a blower-door test, thermographic scanning, combustion gas tests and duct blasting.
A calibrated blower door expels air from the house and measures the amount of air that is leaking in. The auditor determines a leakage ratio to compare with other similar houses. He or she may also calculate the "equivalent leakage area," the size of the hole that would be created in the home if all of the small leaks were combined.
An infrared camera detects temperature variations. Cold or warm air leaks are detected even inside walls, such as where unfilled plumbing and electrical holes run into the attic or where there is insufficient insulation.
A combustion safety and carbon monoxide test will check the combustion gases that are produced from home heating equipment.
Applying the results
Most of the information and recommendations resulting from an audit fall into two basic categories: appliance efficiency and air leaks. An inefficient air conditioner, furnace, water heater, refrigerator or light bulb costs more to operate than an efficient model. But determining whether to replace an appliance requires weighing the costs.
It's easy and inexpensive to replace a burned-out incandescent light bulb with a compact fluorescent lamp (CFL) or an LED bulb, but investing in larger appliances is a bigger decision. "I recommend replacing any furnace that is less than 80 percent efficient," says Erik Lindberg, energy-audit inspector for CenterPoint Energy in the Minneapolis metropolitan area. "The most efficient furnaces and water heaters also feature sealed combustion, direct venting and electronic controls that make them safer and more efficient to operate." Most audits will report how efficient your appliances are so that you can make the efficiency and cost comparisons.
To achieve any benefit from new appliances, you must also ensure that the heated or cooled air doesn't escape from the ductwork or house. "Everybody's worried about cold air leaking into their home, but they don't realize that cold air leaks in direct proportion to the amount of warm air leaking out," Lindberg says.
Even investing in new windows and insulation won't help if air is leaking out through holes in your ceiling such as an unsealed attic access, recessed lights or wiring and plumbing-run holes in the top plates. "The first step is sealing up any bypasses or air leaks into the attic. Start at the top floor ceiling and work your way down," Lindberg recommends. "But as you seal the air leaks in your home, consult a professional to be sure sufficient combustion air is maintained for natural gas appliances that are not sealed combustion models."
How much any recommendations will reduce your bills depends primarily on your willingness to follow through. But you'll never know where the potential lies until you examine the facts. To set up an audit, contact your local utility provider, your state's energy department or the Residential Energy Services Network.
Energy Audit Vs. Energy Rating
You may have heard the term home energy rating or seen a home for sale that is Energy Star rated. These terms refer to an energy-efficiency designation that is determined by an inspection using the Home Energy Rating System (HERS). The inspection is similar to a typical home energy audit, but it's more in-depth. HERS inspections are most often performed on new construction because the primary purpose of the rating is to establish more favorable home financing.
5 Easy Improvements That Will Save You Money
You don't have to spend a lot of money on a new air conditioner, furnace or windows to improve your home's efficiency. These five improvements will lower just about any home's energy bill:
1. Plug leaks into the attic and other unconditioned spaces. Start with leaks at the top of the house and work your way down.
2. Seal leaks around doors and windows with weatherstripping.
3. Install a programmable thermostat, and change the setting when you're not home (8 degrees lower in the winter; 8 degrees higher in the summer).
4. Turn off lights and appliances that are not in use.
5. Replace light bulbs with more efficient CFLs or LED bulbs.