Choosing a Room Air Conditioner

Two-thirds of all homes in the United States have air conditioners. Air conditioners use about 5% of all the electricity produced in the United States, at a cost to homeowners of over $11 billion. As a result, roughly 100 million tons of carbon dioxide is released into the air each year—an average of about two tons for each home with an air conditioner.

Switching to high-efficiency air conditioners and taking other actions to keep your home cool could reduce this energy use by 20% to 50%. The most efficient air conditioners on the market are up to 70% more efficient than the typical room air conditioners found in U.S. homes today. There are steps you can take to lower your room air conditioner's energy use.

A room air conditioner's efficiency is measured by the energy efficiency ratio (EER). The EER is the ratio of the cooling capacity (in British thermal units [Btu] per hour) to the power input (in watts). The required cooling capacity depends on the size of the room being cooled. The higher the EER rating, the more efficient the air conditioner. Look for units with an EER of 10.0 or above. Check the EnergyGuide label for the unit, and also look for room air conditioners with the ENERGY STAR^® label.

Proper sizing is very important for efficient air conditioning. A bigger unit is not necessarily better because a unit that is too large will not cool an area uniformly. A small unit running for an extended period operates more efficiently and is more effective at dehumidifying than a large unit that cycles on and off too frequently. Based on size alone, an air conditioner generally needs 20 Btu for each square foot of living space. Other important factors to consider when selecting an air conditioner are room height, local climate, shading, and window size. The Energy Savers Web site includes a calculator for sizing your room air conditioner.

Verify that your home's electrical system can meet the unit's power requirements. Room units operate on 115-volt or 230-volt circuits. The standard household receptacle is a connection for a 115-volt branch circuit. Large room units rated at 115 volts may require a dedicated circuit and room units rated at 230 volts may require a special circuit.

If you are mounting your air conditioner near the corner of a room, look for a unit that can direct its airflow in the desired direction for your room layout. If you need to mount the air conditioner at the narrow end of a long room, then look for a fan control known as "Power Thrust" or "Super Thrust" that sends the cooled air farther into the room.

Other features to look for:

• A filter that slides out easily for regular cleaning
• Logically arranged controls
• A digital readout for the thermostat setting, and
• A built-in timer

1. Air conditioner cooling, but room is too warm - ice forming on cooling coil behind decorative front.

• Air directional louvers positioned improperly.
  Position louvers to direction upward and away from cooling coils.
• Dirty air filter - air restricted.
  Clean filter.
• Door, windows, registers, etc. open - cold air escapes; hot air enters.
  Close doors, windows, registers, etc.
• Electri-Saver in ON position.
  Set Electri-Saver to OFF.
• Front of unit is blocked by drapes, blinds, furniture, etc. - restricts air distribution.
  Clear blockage in front of unit.
• Insufficient cooling capacity.
  Reconfirm the required cooling capacity with your dealer.
• Outdoor temperature below 70 degrees F.
  To defrost the coil, turn selector switch to FAN position. After coils have defrosted, set thermostat to a warmer position.
• Selector switch set on Low-Cool.
  Turn switch to High - Cool.
• Thermostat set too cold for "nighttime" cooling.
  To defrost the coil, turn selector switch to FAN position. After coils have defrosted, set thermostat to a warmer position.
• Thermostat set too warm (lower number).
  Turn thermostat clockwise to colder setting (higher number).
• Unit recently turned on in hot room.
  Allow additional time to remove "stored heat" from walls, ceiling, floor and furniture.
• Vent control (some models) set at Open position.
  Turn control to Closed position for maximum cooling.

2. Air conditioner heating but room too cool.

• Air directional louvers positioned improperly.
  Position louvers to direction upward and away from cooling coils.
• Dirty air filter - air restricted.
  Clean air filter
• Doors, windows, register, etc. open - hot air escapes; cold air enters.
  Close doors, windows, registers, etc.
• Front of unit is blocked by drapes, blinds, furniture, etc. - restricts air distribution.
  Clear blockage in front of unit.
• Insufficient heating capacity for area to be heated.
  Reconfirm the required heating capacity with your dealer.
• Room temperature is warm enough.
  Heating will not occur until temperature at the thermostat is lower.
• Thermostat set too cool (higher number).
  Turn thermostat counterclockwise to warmer setting (lower number).
• Unit recently turned on in cool room.
  Allow additional time to heat walls, ceiling, floor and furniture.
• Vent control (some models) set at Open position.
  Set control to Closed position for maximum heating.

3. Air Conditioner will not operate on Cool, Fan, or Heat settings.

• House fuse blown or circuit breaker tripped.
  Replace fuse with time delay type or reset circuit.
• Thermostat set to low for cooling or too high for heating.
  Adjust thermostat to higher number for cooling, lower number for heating.
• Wall plug disconnected.
  Push plug into wall outlet.

4. Air from unit does not feel cold on Cool setting.

• Selector switch is in the FAN position.
  Turn switch clockwise to Cool position.
• Temperature sensing tube touching cold coil, located behind air filter (some models only).
  Straighten tube so it does not touch coil and/or insert sensing tube into mounting bracket on coil.
• Thermostat set too warm (lower number).
  Turn thermostat clockwise to colder setting (higher number).
• Thermostat temperature below 70 degrees F.
  Cooling may not occur until temperature at thermostat rises above 70 degrees F