AC Savings

Regular maintenance is vital to get air conditioning energy savings. A thougthful use of thermostats, zoning and a set of some very basic non-cost measures can provide huge AC savings...

Use the thermostat

Adjust your AC thermostat, and turn on a ceiling fan (or the fan associated to the AC system) whenever possible. Circulating fans make people feel more comfortable (and feel 4-6 ºF cooler than the thermostat reading) while using a small fraction of the energy used by the AC.

If you haven't a programmable thermostat, it will be a good idea to install one. Properly programmed, programmable thermostats can help you to save up to 15% in energy.

For other cooling strategies, see: Alternatives to Air conditioners

Low cost ways to get aC savings

Some non-cost or very low-cost rules may reduce your air conditioning bills:

- adjust the air conditioning thermostat settings with seasons. In summer and hot weahter you will get significant AC savings for each degree higher you set your thermostat. You may set your thermostat at 78ºF in the summer and at 68ºF in the winter, knowing that for each degree cooler in the summer (or for each degree warmer in the winter) your energy bills will increase by 4-6% or more.

- adjust the use of air conditioning to the presence of people in the house; programmable thermostats can be set to keep your house warmer during the day, when you are absent. And you can set it to automatically cool some time before you get home.

- use the AC fan-only option during the night;

- use shades, awnings, blinds, window films (or trees in the outdoors…);

- whenever possible locate condensers (of outside AC units) under shade. The AC effciency will increase.

- in high humidity days, set the AC fan speed on Low;

- Don't block the area around your AC condenser (outside unit). High grass, trash or fences around it will block free air flow and will cause higher consume.

- ask an air conditioning professional to install timers or switches to shut the air conditioning off when not in use.

Thermostats

Use programmable thermostats to set the temperature up (when leaving the home) and down (some time before entering).

You may save 4-6% on your air conditioning bills for each degree you raise the thermostat... A thermostat setting of 78ºF/26ºC should be sufficient to make your home comfortable in the summer.

See: Thermostats basics

Ventilation and fans

Use fans and ventilation instead of air conditioning, whenever possible. Ceiling fans (and other types of fans) can be very effective. Consider also cross and natural ventilation.

See: Ventilation and fans and Natural ventilation

Doors and windows

The doors (and windows) of rooms being cooled by room and portable air conditioners should be closed. If you have a room/window AC, closing off unused rooms will provide more cooling to the used areas.

Also do not operate your central air conditioning without keeping the windows and the entry doors closed.

Registers

Don’t cool unoccupied rooms, but also do not shut off too many registers. That will put pressure on the air conditioning system.

Inefficient appliances and AC

Do not forget that new high-efficiency AC systems allow large AC savings: up to 30 to 40%. They can pay themselves in energy savings in a short time.

Get rid of inefficient appliances (and also of old air conditioners). Old refrigerators and other domestic appliances are energy-inefficient, emit too much heat and require higher loads of air conditioning. Also replace incandescent light bulbs with CFL (fluorescents): they emit less heat and are more energy-efficient.

Outside air options

If your room air conditioner has an outside air option, use it as little and sparely as possible.

Clean the air filters

Clean or replace the AC air filters regularly (once a month...), during the cooling season. This is the immediate best single way to get AC savings. Dirty filters impede normal AC airflow and may increase operating costs up to 10%. Dirty air filters will make your cooling system (or your heating system) to work harder than necessary.

See: Central and Room AC filters

Pay attention the the ductwork

Leakage in AC ductwork (central AC) will increase the cooling bills. Auditing and sealing them carefully can bring high AC savings.

Do regular maintenance to get higher AC savings

An adequate 1) refrigerant charge, 2) airflow, 3) cleaned coils and 4) properly insulated and non-leaking AC ducts… are critical for air conditioning savings.

Fixing problems in any of these areas can easily improve AC savings by 10%-20%... Keeping the AC coils clean will keep the system at top efficiency.

See:
Professional AC Maintenance
AC Refrigerant charge
Cleaning AC Coils
AC Blower
Window air conditioner maintenance
Air Conditioners Size and Charts
Air Conditioners Performance