Central Air Conditioning Maintenance & Cleaning

It’s finally summer and warmer temperatures are on the way. That’s good news, unless your home air conditioning system is on the fritz! And if you haven’t had your air conditioner checked recently, now is the time to do some maintenance, before the first big heat wave arrives.

Inspecting and maintaining a central air condition is not that difficult; most do-it-yourself homeowners can learn how to check proper operation and perform basic system cleaning and preventative maintenance. More complex repairs, maintenance tasks and updates may require an expert. You should have your system checked periodically by an expert even if you do most of your own maintenance.

With proper installation, cleaning and maintenance, a modern central air conditioning system should last at least 10 to 15 years. Read on to learn how to get the most from your home A/C system.

Central Air Conditioning Maintenance Tips

Most central air conditioning systems are connected to the forced-air heating and cooling system and have two separate components; a condenser (usually installed outside the house) and an evaporator (usually mounted in the plenum or main duct above the furnace). Inspect your furnace filter monthly; clean or replace the filter every month during the summer and winter months when you run the air conditioning (or heater) most frequently. Basic maintenance includes:

  • Check hose connections, visually inspecting for cracking or leaks that may need to be repaired.
  • Check to be sure that the “condensate tube” drains freely.
  • Use a garden hose with a spray nozzle to periodically wash the compressor located outside.
  • Keep plants at least a foot away from the condenser and trim tree or plants that hang over the unit; better not to have them draining water and dropping debris onto it.
  • Vacuum the air register vents in your home regularly to keep dust from building up. Do not place furniture or other objects where they cover the registers.
  • Once a year or every other year at the most, have your ductwork cleaned by a professional.
  • Cover your outdoor air conditioning compressor with plywood during the winter months to prevent corrosion or damage from falling ice or debris but do not wrap it in plastic or materials that block good air flow; you don’t want to trap moisture.
  • Remember to call an HVAC professional early in the season; waiting until a heat wave usually means delays!

Use Your Central Air Less Often

The best way to save money on cooling your home is to avoid using your central air conditioning system any more than needed. This not only reduces fuel costs but also prolongs the useful life of the central air condition system itself. Follow these tips to keep your home cool and reduce the need to turn your on A/C:

  • Plant trees around your home to help shade it from the sun.
  • Install ceiling fans and use floor fans as needed to circulate air during hot weather.
  • A whole home fan system can lower temperatures inside your home by ten degrees in a few minutes; these systems are becoming more popular as fuel costs increase.
  • A well-insulated home stays much cooler; be sure your home has adequate ventilation and insulation in the attic; ridge vents, an attic fan and soffit vents or gable vents are critical to keeping your home cool during the hot weather.
  • Electric lights emit heat; keep them off when not in use. Timers and sensors are a great ways to control lights in your home.
  • Avoid using heat emitting appliances such as the oven, dishwasher, laundry clothes washer and dryer and others during the heat of the day. Wait until evening, when its cooler, to clean the dishes and clothes; hey, it’s a good excuse anyway!
  • Check with your gas and electric provider to see if they offer incentives for lower usage during peak conditions, adding or upgrading insulation, door and window seals or other home efficiency improvements.

Central Air Conditioning System Components

Proper installation and configuration of a heating and air conditioning (HVAC) system is a complex project that greatly affects its efficiency and longevity. As a major investment in your home, the HVAC system deserves at least a basic understanding of the system components and the purpose of each:

Outdoor Compressor and Condenser – The most visible component is the compressor / condenser unit, which is usually installed outside the home. Cleaning the condenser coil located inside the compressor unit is one important maintenance task that needs to be performed annually unless otherwise specified by your manufacturer.

Indoor Evaporator – A major component of your home cooling system is the evaporator, which is generally co-located with your furnace in the garage or other service location. A number of regular maintenance steps need to be followed; see section below on cleaning instructions for details.

Refrigerant – Inside the Evaporator, copper tubes carry refrigerant that absorb heat by circulating it through the evaporator coil, cooling the air flowing into the home. The hot air is then released at the outdoor compressor’s condenser coil.

Ductwork – Sheet metal ducts carry the cool air to various rooms in the home. These must be properly insulated and should be checked periodically. The only way to remove dust and particulate matter inside the ductwork is to have it professionally; the skills and equipment required just aren’t within most homeowners’ repertoire.

Registers and Vents – The ducts terminate at registers; covered vents in the floors, walls and/or ceilings inside the home.

Tubes and Lines, Connectors and Wiring – Proper maintenance includes inspecting and replacing various lines and cables as needed. 240 volt electrical power is most often used.

Instructions to Clean Your Central Air Conditioning System

Several maintenance and cleaning steps are most important and also simple to do; allow 2 to 4 hours, depending on the size of your home, your own familiarity with the system and maintenance steps and the condition of your system.

It should be mentioned that having this maintenance done professionally generally costs between $100 and $300, so doing it yourself may or may not be worthwhile in your own situation. But if you like knowing the job is done right doing it yourself can save a few bucks. And hey, you’ll know more about your central air conditioning this way and can better detect problems before they arise and be sure you get the best value possible when you do need to hire a professional expert to handle repairs and upgrades!

Cleaning the Outdoor A/C Unit (Compressor and Condenser)

  1. Begin by shutting off electrical power to the entire system; most units have a covered 240 volt power switch located on the side of the house near the unit.
  2. The most important job is cleaning the condenser coil; a fan basically sucks outside air through the fins, leaving them covered with lawn clippings, dirt, bugs, dead leaves and other crap. Add in a little moisture and you have the perfect place for dirt and grime to build up. This fun little chore may need to be done every couple of weeks during the spring when dandelion "wishies" are flying! Use a garden hose and a soft nylon brush to clean the condenser coil fins.
  3. Two copper tubes connect the compressor and the condenser coil to the evaporator coil back inside the house. One or both should have insulation, depending whether or not your system has a heat pump. Visually inspect the insulation for signs of wear or damage.
  4. Most units have a sealed, maintenance-free fan motor; look for lubrication ports or check the manufacturer’s manual to be sure whether or not it needs to be oiled.
  5. Your system owner’s manual should explain how often the refrigerant needs to be recharged; this is not a service you can perform yourself so call in a pro! If you see any signs of refrigerant or oil leaking inside or around the compressor or condenser, its also time to give your A/C pro a call.
  6. When you have completed servicing the outdoor compressor unit, you need to follow some precautions to restart the system to prevent damage. If the unit uses a 240 volt power connection set the indoor thermostat to the off position. Switch the 240 volt switch back on and wait 24 hours before running the system to allow the warming element to heat up the lubricant inside the compressor. Set the thermostat to the “cool” position to check the system for proper functioning.
  7. Always wait at least five minutes anytime you turn the system off at the thermostat; this prevents overstressing the motor by restarting it while it is decompressing. Some units have a circuit delay to prevent this problem.
  8. Most outdoor compressor units are mounted on a concrete pad; use a garden hose and stiff brush to keep dirt, moss, etc. from building up around the base and on the cover of the unit.
  9. Don’t clean your outside compressor if the outside temperature is below 60 degrees F; a compressor won’t work in cold temperatures so testing the system after maintenance won’t be possible.

Cleaning the Indoor A/C Unit (Evaporator)

  1. You should check the furnace filter monthly and replace it regularly to prevent dust from building up on the evaporator coil fins. Be sure the blower is turned off before you pull out the filter so that no dust is accidentally blown through the system by having the blower come on with no filter in place.
  2. If applicable per your manufacturer’s directions, with the power off, open the blower compartment to lubricate the motor with electric motor oil; you should see lubrication ports if your unit requires periodic lubrication. Use a shop vac to remove dust inside the compartment before closing everything back up.
  3. Next, check the condensation drain to be sure it is free of algae, sludge or other grime that could cause it to clog; you can use a mixture of 1 part bleach to 16 parts water to clean out the drainage tube. Flexible drain tubes are usually removable while some units have a rigid plastic tube that is fixed; insert a piece of wire to inspect the tube for clogging.

15 Responses to Central Air Conditioning Maintenance & Cleaning

  1. Pingback: Central Air Conditioning Maintenance & Cleaning | Chicago Air Conditioning Service & Repair

  2. Kevin says:

    This is really a great list of things to do when it comes to air conditioning maintenance and getting the most out of your hvac equipment. I do want to stress that the one component that costs you the most in energy consumption is your indoor blower motor. Your indoor fan works in summer and winter and can get coated with lint and other materials on the blower wheel blades. Here is an important note, the only way a service technician can clean those blades is to pull the entire blower housing out of your furnace or air handler and unfortunately you see a lot of techs just stick a vacuum in there for show and aren’t really doing anything useful. That’s why I’m not afraid to charge my customers a little more because it allows me to take the time to do a better job. In addition to maintenance there are some excellent developments in green building technologies like solar power, geothermal and even as you mentioned landscaping can play a significant roll in energy savings. There’s some really cool green building design going on for example, in commercial hvac applications you can reduce blower motor energy consumption by decreasing a systems duct size in conjunction with a variable speed motor that runs slower and uses 20 to 30% less energy and remember that thing is running almost all year round, this is a significant savings for commercial and residential buildings especially when you scale it to high rises and skyscrapers that are found in downtown Chicago for instance. I’ve ranted on probably long enough but I did enjoy your post, keep up the good work and it’s a great site!

  3. Rafter Tales says:

    Thanks for the great tips Kevin; always great to see what advice a pro has to offer. If you’d be interested in writing a guest article on the site please contact us.

  4. Chuck says:

    Those are great tips unless you have a geothermal system. Then the only maintenace is changing filters.

  5. Ifeoma Uchechukwu says:

    The lesson was good but it would have been better, if the functions of each part of the AC was stated and explained.

  6. Brett says:

    I think all of the previous explainations have been great. Thanks a lot.

  7. Thank you for sharing this post! I'm sure many of us learned much from it. hope you could post more regarding maintenance and repair, as this s a common concern o those who are having air conditioning unit.

  8. Sergey says:

    Great  instruction article!

  9. Olga Lantz says:

    I think that manufacturers of all home products, such as “Central A/C and Furnace”, should consider that a lot of these maintenance requirements are now done by WOMEN!!.I have found that it requires a lot of strength to disassemble and re-asemble these units.

  10. Thanks for posting this air conditioning maintenance check list. I’m going to refer my customers to read this article as it will help them to understand the importance of maintaining their AC system.

  11. love the article, will bookmark it on my site!
    thank you for value info.

  12. Pingback: How your HVAC system works! | HVAC Repair Phoenix

  13. Pingback: Central Air Conditioning Maintenance Tips « Scardina

  14. Emma Stokes says:

    Your tips for maintaining your A/C unit is great. I think if u added pictures to your text for people who dont know what a compressor or condenser looks like will be very benificial.

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