Cool air feels good, but high utility bills do not. Efficient air conditioners can save you serious money over the life of the system and keep you just as cool.

When you are considering the efficiency of an air conditioner, size is everything. Oversized and undersized can be equally bad. When a unit is oversized, it will cycle over and over. The constant starting and stopping of the unit will pull more energy, and the dehumidifying properties of the cooling coils will not have time to fully operate. This will result in moisture being blown into the duct works and the ambient air with each start up. If the unit is undersized it will not be able to generate enough cooled air to maintain the desired temperature, and will run constantly.

Air conditioners are rated on their efficiency using a measurement known as the Seasonal Energy Efficiency Ratio (SEER). This measurement is the cooling output divided by the energy consumption with climate and certain other variables factored in. The higher the SEER number, the more efficient the unit, is the general rule. Older units might have a SEER as low as 7 or 8. For a long time, The Department of Energy mandated a SEER of 10 as the minimum for all newly installed units. This figure has recently been raised to 13, and is a topic for debate currently. Some units are capable of SEER ratings as high as 17 or 18.

Window units use EER (Energy Efficient Ratio) rather than SEER, but the principle is basically the same. The principle of “bigger is not necessarily better” applies to window units also. Humidity plays such an important role in comfort, and is often more important than just mere temperature. Smaller units tend to remove more moisture because they have longer runs. When a unit first starts it actually blows a bit of moisture out of the unit. Once the cycle is running smoothly, the condensation of moisture on the cooling cools begins. Therefore, a longer running cycle is going to provide a more comfortable environment.

There are other factors that will increase the efficiency of an air conditioner and result in a reduction of operating expense. A programmable thermostat is one such idea. The thermostat can be set to automatically raise the ambient temperature at night during sleep or when the home is vacant during working hours. A ten degree raise in temperature setting during these time periods can result in a ten percent reduction in operating costs.

Properly maintaining your system will also result in increased efficiency. Routine changing of filters is one of the most important maintenance requirements. Efficiency of air conditioning is an issue that goes beyond savings to the owner of the home or building. It is an issue of national concern. The wide spread use of air conditioning has created a large strain on electrical power demand especially during heat waves. Power generation is struggling to keep up with demand and brown-outs have become frequent during periods of high demand. Air conditioning efficiency takes place on an individual level, but the air conditioning industry is working to improve efficiency with improved models and the development of new technology as well.

Water removed from the air during operation falls down the cooling coil and drops into the base. From here it follows channels or passages to the rear of air conditioner. Some of the water is lifted up by the fan blade and used to cool the heating coil, while most proceeds to the rear. Once at the rear it drops out of the base and onto the ground. That is, if everything is working perfectly.

The reality of window air conditioners is that they can leak water. One that leaks can drive you crazy trying to find the cause of the problem. The following are a few suggestions of the most common reasons why water leakage occurs.

1. Improperly installed.

A window air conditioner must be slightly lower at the rear than the front. This allows the water being removed from the room to drain to the back of the machine. A difference of one inch is sufficient. This is always the first thing to check. Many are improperly installed in the haste to get relief from the heat. If installed too low at front the water will flow into the room rather than outside. If installed too low at rear, water can roll out front edges before has chance to exit towards rear drain.

2. Icing up.

Water being de-humidified can turn to ice if there are problems with the cooling system. There are many reasons for an air conditioner to produce ice. Remove front grille while machine is operating. If ice is present on the cooling coil you will probably need service. For more information see our other article: Why window Air Conditioners Ice up.

3. Air leakage around air conditioner.

If warm air is able to enter around the air conditioner it will encounter cooler, dryer air. When they meet condensation will occur. If water leaking from front of air conditioner inspect to see if dripping from body of machine, or water droplets clinging to front area. To test, operate machine for 30 minutes and then use flashlight to check under front edge of base. Small water droplets here indicate an air leakage problem. Add foam insulation to stop warm air from infiltrating.

4. Drain hole blocked.

Rear of air conditioner base has a drain hole or groove to allow water to escape. If becomes blocked water can back up. To test, operate machine for 30 minutes and then inspect if draining properly. If appears blocked use a small piece of wood to open drain hole at rear of metal base. CAUTION: Never be tempted to drill holes into the air conditioner body to relieve water pooling. Severe damage can result.

5. Internal drains blocked.

There are small passageways that allow water to drain from front of air conditioner to the rear. If they become blocked water will pool at front of machine and overflow onto floor. If this happens the air conditioner will require removal from window and servicing.

6. Outside temperature too cold.
This occurs at end of cooling season. If outside temperatures drops below 60 degrees Fahrenheit at night the cooling coil may ice up. If no leakage at bedtime but water in front of machine in morning, suspect this problem. If this problem suspected turn off machine before bedtime and restart as day warms. Alternately, operate machine at night with selector switch in ‘fan only’ position. This will circulate room air during night but not allow cooling.

Copyright 2005 by Donald Grummett. All right reserved. Donald Grummett is an appliance service manager in Ottawa, Canada. In the trade over 30 years as a technician, business owner, and technical trainer. Learn more invaluable information about your household appliances by visiting http://www.mgservices.ca