A window-mounted room air conditioner is a great solution for beating the summer heat without breaking the bank. But like central air-conditioning systems, room air conditioners require periodic maintenance. They also require proper sizing for the room or rooms they are used to cool.
With heating and cooling systems, bigger is not always better. Oversizing a heating or cooling appliance such as an air conditioner will reduce efficiency, worsen performance, and increase energy costs.
The Importance of Properly Sizing a Room Air Conditioner
The cooling size of an air conditioner is measured in its ability to extract a certain amount of heat measured in British thermal units, or BTUs. A common mistake when buying a room air conditioner is purchasing a unit too big for the size of the room (i.e., too many BTUs).
Why is this a problem? Because a key element of feeling "comfortably cool" is removing humidity from the air as well as reducing the room air temperature. While an oversized unit may quickly reduce air temperature, it will not properly reduce humidity or run efficiently. Oversizing results in humidity discomfort and expensive operation.
To properly size a room air conditioner, use the sizing chart provided by the Energy Star program of the DOE (Department of Energy).
Early Season Maintenance
Waking up your window-mounted air conditioner from a winter slumber involves just a few steps:
- Remove the outdoor cover from the outside of the air conditioner. Note: If you don't have a cover, be sure to check the inside of the unit carefully for insects or small animals or their nests. If you remove your air conditioner from the window for off-season storage, pull it out from storage but do not reinstall it yet.
- Thoroughly inspect the unit, unplug it from the wall, remove the front access cover, and remove the air conditioning unit from its mounting frame.
- Take the unit outside and vacuum out the condenser coils with a soft brush attachment. You can also hose off the coils from the inside out taking care not to get the electronics or motor wet.
- Check the condenser coil for bent cooling fins. If several fins are bent, straighten them with a coil fin comb, matching the teeth count of the comb to the "fins per inch" of the coil. Carefully draw the comb across the bent coil fins to straighten them.
- Inspect the foam air filter for dirt and damage. If it is ripped or damaged, replace it. If the filter is dirty, wash it with dish soap and water, let it dry, and reinstall it.
- Replace the unit into its frame. Reinstall the front cover, and plug in the unit to the electrical outlet.
Regular Seasonal Maintenance
The maintenance steps for starting up your window air conditioner at the beginning of the cooling season will get your unit in shape for the first month or so. After that, check the filter each month, and clean it as needed.
Also, check the water pan on the inside of the unit, and clean it with a rag or sponge as needed. Keeping the pan clean helps ensure proper drainage of the condensate created by the unit, and it helps prevent mold growth.