Air Conditioner Efficiency Ratings

In general, when it comes to efficiency, the more efficient the unit, the more it will cost initially. However, a more efficient, therefore more expensive, unit will actually save you money over time as it requires less fuel to cool your home.

If you are concerned about efficiency, watch for the Energy Star label. Cooling efficiency for air conditioners is indicated by a SEER (Seasonal Energy Effiency Rating). The SEER rating tells you how efficiently a unit uses electricity: the higher the number, the greater the efficiency. The typical SEER rating of units manufactured prior to 1992 is about 6.0. In 1992, the government established a minimum cooling efficiency standard for units installed in new homes at 10.0 SEER. High efficiency units have a rating of at least 12.0 SEER. If for your new home, you are looking for a highly efficient unit, consider the Lennox Elite 13 or the Amana RCE Prestige Ultra.

Sound Ratings

The cooling effect on an air conditioning will go under appreciated if every time it is on you go crazy because of the noise. Depending on the location of your outdoor (condensing) unit and the floorplan of your home, your unit will either disturb you indoors or outdoors. A noisy unit may destroy the peace and quiet in your yard, or interrupt your child's nap. The sound level of outdoor units is measured in bels (similar to decibels), on a scale from 0 (barely perceptible) to 13 (the loudest).

Most air conditioners operate at 8 to 9 bels. The quietest units operate at 6.8 bels. This may not sound like a wide range, until you learn that a 9-bel unit is 10 times louder than an 8-bel unit. In other words, one 9-bel unit makes as much noise as 10 8-bel units put together. If you are looking for a relatively quiet unit, consider the Amana Prestige Ultra RCE with its sound blanket and its quiet low (850) RPM Condenser Fan or a Lennox Elite 13 or Lennox Merit 12. These Lennox units use scroll compressors instead of traditional piston-driven compressors. The scroll compressors and these units' precision balanced direct drive fan allow them to operate without producing so much noise.

Comfort Features

Some air conditioners come with additional features that provide greater comfort. Two-speed units can run on low-speed (using about 50% of the energy) 80% of the time. Consequently, they use fewer on/off cycles and produce fewer drafts and much small temperature swings.

Select the Correct Size

One thing you cannot forget is the size. If you have a large house you need an air conditioning unit that will be able to cool the whole thing. In other words, in order to achieve comfortable cooling and dehumidification, the system must be correctly sized. Traditionally, central air conditioning units have been sized in tons, with one ton cooling 12,000 BTUs per hour. However, things have changed, with the exception of the highest SEER equipment (16 SEER and above), most new equipment is cooling fewer than 12,000 BTUs per ton. Thus, if you need to replace your existing equipment at your home or place of business, you may have to buy a larger unit (more tons) than your present unit, in order to get the same amount of cooling. So, don't just look at the AC in your old house and assume you need the same one, check the newest regulations. Have an experienced air conditioning technician visit your residence or business, run a heat load, and identify the size and model of equipment which will meet your cooling needs.

If you do not want to go to that trouble, you can always use the general rule of thumb, you need 12,000 BTUs of cooling for each 500 square feet of living space. This ratio assumes that the space you are cooling has standard 8 foot ceilings, that windows make up less than twenty percent of southern facing walls, that your windows have drapes or blinds and that you close them during the heat of the day, and that your walls and attic are insulated. If this is not the case for you, then adjust for your considerations

Bigger is not always better. An over size unit will lower the temperature too quickly and will shut off before it has an opportunity to properly dehumidify the air being conditioned. Excessive humidity can create an environment which facilitates the growth of mold.

When it comes to air conditioning you can know what the things mean, but you should have a trained technician come out and assess your house, or at least your floor plans to find the best one specific to your needs.