It's easy to take your air conditioner for granted... until it stops working on a miserably hot day. If possible, have an air conditioning contractor inspect your unit before you start using it each summer. Regular maintenance will not only help spot potential problems, but will also increase the life and energy efficiency of your unit.

What you can do

• Clean up around your air conditioner. Outdoor condenser coils can become dirty and blocked, which makes your unit work harder and increases your cooling bill. Your dryer vents, falling leaves, and lawn mower are all potential sources of dirt and debris. Allow for adequate air flow to your unit by cleaning the area around the condenser coil, removing any debris, and trimming foliage back at least 2 feet.
  
   
• Change your air filter regularly. Inspect your unit's air filter once a month and clean or replace filters as necessary. Keeping the filter clean can lower your air conditioner's energy consumption by 5% to 15%. Ask your service contractor to show you how to do this, if you aren't familiar with the process.
  
   
• Keep your condensation line clear. Condensate lines drain away the moisture your air conditioning unit creates. A plugged condensate drain can cause water damage in the house and affect indoor humidity levels. You can help keep the line clear of mold and mildew by pouring in a small amount of household bleach. Ask your service contractor to show you how.

When you hire a service contractor
When you do your pre-season check, ask the technician to do the following:

• Check for correct amount of refrigerant
• Test for refrigerant leaks using a leak detector
• Capture any refrigerant that must be evacuated from the system, instead of illegally releasing it to the atmosphere
• Inspect for and seal duct leakage in central systems
• Measure air flow through the evaporator coil
• Verify the correct electric control sequence and make sure that the heating system and cooling system cannot operate simultaneously
• Inspect electric terminals, clean and tighten connections, and apply a non-conductive coating if necessary
• Oil motors and check belts for tightness and wear
• Check the accuracy of the thermostat

Trouble spots
Look out for these things that can compromise cooling power and energy efficiency:

• Leaky ductwork. Leakage from areas such as ductwork joints, elbows, and connections can be substantial -- as much as 20% to 30%. This is especially costly if the ducts travel through unheated or uncooled spaces such as attics, basements, or crawl spaces. Use duct tape or caulk to seal ductwork.
  
   
• Thermostat placement. Don't place lamps or TV sets near your air-conditioning thermostat. The thermostat senses heat from these appliances, which can cause the air conditioner to run longer than necessary. Make sure your thermostat isn't placed in the light of a sunny window.
  
   
• Thermostat abuse. Don't set your thermostat at a colder setting than normal when you turn on your air conditioner. It will not cool your home any faster and could result in excessive cooling and, therefore, unnecessary expense. Install a programmable thermostat so you can automatically reduce the temperatures during low-occupancy hours.