Checklist: Air Conditioner Maintenance

Check the outside condensing unit

Some people intentionally cover their condenser to protect it from the elements during the winter, but these units require no protection since they are designed to be outside.

Run your air conditioner before regular use
Run your air conditioner for a few minutes before you actually need it, in late spring or early summer. If you wait until the first hot day then discover it isn't working, you'll find yourself on a waiting list, sweltering for days before an air conditioning specialist can come to repair it.

Change the air conditioner's filters regularly
Dirty filters restrict air flow, reduce efficiency and worst case, can cause the evaporator to ice up. Disposable fiberglass filters should be replaced. Electrostatic or electronic filters need to be washed regularly.

Check the access panels
Be sure all access panels are secure, with all the screws in place.

Check for obstructions
Clean obvious obstructions, such as newspaper and leaves, from around the exterior of the unit.

Set the correct mode
Be sure the thermostat is set in the cooling mode. Just setting the dial below room temperature will not activate the air conditioner if it is set in the heat mode.

Never use water to clean your air conditioning system
A thoroughly cleaned air conditioning unit will operate at top efficiency. However, homeowners are strongly discouraged from cleaning it themselves by using a hose and water because of the serious risk of electrical shock and possible shorting of electrical components.

Thomas Fishler, Thomas Fishler's Heat & Air Conditioning & Duct Cleaning, Carmichael, California.