Today's homebuyers often shop around for the best mortgage interest rates, knowing that even a few tenths of a percentage will save thousands of dollars over the life of the loan. Yet they often don't recognize that energy-efficient construction in that new house will also save them thousands of dollars over the years they live in the house.

The typical U.S. household spends $1,000 to $1,500 each year on utility bills. Of this, about half goes to heating and cooling, a third to appliances and lighting, and about an eighth to water heating.

Energy-efficiency features can reduce your power bill by several hundred dollars a year. Look for homes with the following features. If you're building a house, it's worthwhile to pay for upgrades in these features. A small investment today can mean long-term savings.

Insulation

Insulation is measured in R-value, which measures its resistance to transferring heat. For energy efficiency, look for wall values of at least R-11 and ceiling values of at least R-30.

Windows

The most efficient windows for this climate are double-glazed windows filled with a non-conducting gas — usually argon — and coated with a transparent low-emissivity coating. Low-e coatings reflect infrared heat radiation, helping keep the heat outside in summer and inside in winter. Double-glazed, low-e windows reduce heating and cooling costs more than 30 percent over single-pane aluminum windows — or about $100 a year for a typical 2,000-square-foot home.

Heating and Cooling

Another place where an initial investment can save in the long run is in the selection of the heating and cooling system. Sealing and proper installation of the HVAC system are the most important and often, most overlooked factors. Look for a heat pump with a Heating Season Performance Factor (HSPF) greater than 7 and Seasonal Energy Efficiency Ratio (SEER) rating of at least 12. A central air conditioning unit should have a SEER rating of at least 12.

Appliances

Choose energy-efficient appliances and lighting. The EnergyGuide labels on major appliances show the appliances' estimated energy use and annual operating costs. Light fixtures used more than two hours a day are good candidates for fluorescent bulbs. In general, look for the Energy Star label, the U.S. Department of Energy's symbol for energy efficiency, when shopping for heating and cooling systems, appliances, lighting and windows.

Sealing

Good insulation won't make up for air leaks around penetrations such as water pipes. Builders who want to improve energy efficiency take special care in sealing any possible air leaks.

Buying an energy-efficient home — or improving the energy-efficiency of an older home — will also pay off when you go to sell your home.

According to a recent survey by Professional Builder magazine, energy efficiency is the number-one upgrade that homebuyers ask for. A related survey, however, showed that builders underestimate the value that consumers place in energy and resource efficiency.

You can see how well your builder met energy-efficiency standards by getting a Right Choice High Tech Audit of your home's energy efficiency and air quality. However, the simplest way to make sure you're buying a very energy-efficient home is to buy a Right Choice home.