The Energy-Efficient House
Ceiling Fans Clothes Washing Dishwasher Ducts Heating & Air Conditioning Lighting Range Refrigerator Solar Cells Solar Water Heating Televisions Water Heater Windows

Ceiling Fans

By lowering the need for sensible cooling, ceiling fans can save noticeably on air conditioning. One study suggested an 8% cooling savings in a Texas climate if the thermostat set point is raised 4 degrees.

However, this is only valid if the thermostat is indeed turned up. And electricity can be wasted if the fans are left on when one leaves the room or the house. Fans will not make the furniture and the floors any more comfortable.

Clothes Washing

Clothes washing can use more than 10% of the electricity in a single fuel home in the hot and humid climates in the U.S. However, the electricity used by a clothes washer itself is often less than 4% of the electricity used in the overall laundry process. So washing machines are rated by how much energy is used in the total process to heat water, agitate the clothes, spin them mostly dry, and then complete the process with clothes dryers.

The best clothes washer on the market in 2019 saved 75% of the energy compared to the minimum requirement in 2004, when the first federal standard took effect. It also saved 71% of the water used in the average unit sold in 2010, when the first federal standard took effect.

Using cold water for washing and clothes lines for drying eliminates almost all of the energy used for laundry purposes.


Dishwashers use more than 1% of the energy typically consumed in a home in the hot and humid part of the U.S. when water heating is considered.

The best dishwasher on the market in 2019 saved 75% of the water compared to the minimum requirement for a unit sold in 2010, when the first federal standard took effect. The best unit also saved 57% of the energy compared to the minimum requirement for a unit sold in 2004, when the first federal standard took effect.


In general terms, duct sealing and balancing is the most important energy measure you can employ for an old or new house. Ducts in a typical home leak 25% of the conditioned air, which is most of the air leakage in a house. Some poorly built apartment units can leak as much as 45%! With proper sealing, this can be reduced to 10%. “Balancing” air delivery by installing larger ducts to allow more air to enter a room or relief vents that prevents over-pressurized rooms improves comfort and lowers bills.

There are air quality benefits from this retrofit as well. Leaking ducts can pull supply air in from a garage that is contaminated with chemical fumes, a yard with pesticides, or an attic with mold or dust.

Heating & Air Conditioning

In hot and humid climates in the U.S., cooling uses 1/3 of all electricity. For electrically heated homes, about 11% of total electricity is used for space heating. For homes heated with natural gas, about 53% of total gas is used for this purpose.

The most cost effective ways to save on heating and cooling energy are to seal your air ducts, apply caulking and weatherstripping, and place solar screens over older windows. However, if you are replacing your unit, get a high-efficiency air conditioner. If you heat with electricity, install a heat pump. If you already have a heat pump, install a higher efficiency unit.

For those who want to get top-of-the-line equipment (which does not always yield a quick payback), consider central units with inverters, minisplit units that cool each room or area of the home without ducts that can leak air, or geothermal heat pumps that use the earth’s temperature to heat and cool.


In the hot and humid Southern U.S., lighting used about 8% of the electricity in the average home.

Light Emitting Diodes (LEDs) can save 80 to 90% of the energy used by incandescent bulbs sold just a few years ago. And saving electricity on light means saving electricity on air conditioning.

However, make sure that the LEDs you buy have a good Color Rendering Index (color quality) of 90 or above. And if you place them in enclosed fixtures or use them with dimmer switches, make sure the LEDS are designed for them. Otherwise, lamp life will be greatly reduced.


Electric cooking uses about 1% of the electricity consumed in a single-fuel home in the hot and humid part of the U.S.

Induction cooking can lower electric use, but only in certain situations. If a cooking vessel does not completely cover a burner, induction cooking can save as much as 46% compared to a strip-heat electric range. But if a cooking vessel completely covers the burner, strip heat can actually be a little more more efficient than induction cooking, because it captures the heat emitted from the burner much better.

Induction strip heating is still expensive if purchased as a range/oven unit. However, single burners can be purchased at much lower prices.


Refrigerators are the most energy-consuming appliance after water heaters. In the hot and humid Southern U.S., they use about 6% of electricity consumption.

Electricity use per unit has fallen 45% since 1990. However, the most efficient unit sold today can save 69% compared to 1990 levels.

Solar Cells

Solar cells can provide most/all of your electricity consumption on an annual basis. However, you should reduce your needs with energy efficiency measures and efficient appliances as much as possible before you self generate.

Solar Water Heating

In hot and humid climates in the U.S., solar thermal water heating can save 70% to 75% of the energy used to create hot water.

A recent innovation is a solar-cell assisted heat pump water heater, which uses direct current electricity to provide resistance heat during daylight hours.


About 1/6 of the electricity used in homes in hot and humid climates in the U.S. is from "plug loads," from niche appliances to electronics. About 1/3 of these plug loads is from TVs and associated home entertainment equipment.

Buying efficient televisions, electronic devices, and computer equipment carrying the Energy Star label is one of the best ways to manage plug-load costs.

Water Heater

In hot and humid climates in the U.S., water heating makes up 14% of consumption in electrically heated homes. For homes with natural gas, about 34% of total gas consumption is used for this purpose.

Quick payback measures include installing low-flow showerheads and aerators, or if you have them, installing better ones. If you have a garage or basement and use electrically heated hot water, consider upgrading to a heat pump water heater, which can save 50% and more compared to standard “strip heat.”

Tankless water heaters also save energy. However, the cost is so high that you will rarely get a quick payback in a residence. These are more appropriate for commercial uses serving large numbers of people such as laundries and restaurants.


New windows for existing homes do save energy. They do several other good things as well, including reducing noise, dust, and sometimes insects. However, if the only reason you are buying a new window is to save energy, and your existing windows have good weatherstripping, then consider solar screens instead. They are much more cost effective.

When considering windows for old or new homes, look for a Solar Heat Gain Coefficient of 0.35 or lower. U-value, the insulation effectiveness in the frames, is also good for comfort. Again, a value of 0.4 or lower is good. However, while U-values are good for comfort, in the Southern U.S., they do not save a lot of energy relative to their cost.

Also important is what the frame is made of. Frames made with vinyl and ABS plastic are derived from toxic chemicals. Wood, fiberglass, and aluminum are much more sustainable (though aluminum has lower U-values).