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Air conditioning doesn’t get nearly the respect it deserves for being an amazing technology. Air conditioners make previously inhospitable parts of the country livable, providing the moderate temperatures needed for safe work and play and comfortable living. They can only do this important work if they are well-maintained, which includes ensuring that components like their condenser coils and evaporator coils are cleaned regularly.

More than 75 percent of homes in the U.S. have air conditioners, and these devices consume about 6 percent of all electricity produced here, costing homeowners about $29 billion per year. Unfortunately, a significant portion of that energy consumption is waste caused by inefficient air conditioning units.

Improving the energy efficiency of your air conditioner can greatly reduce your energy bill. In some hotter parts of the country, electricity costs related to operating an air conditioner can make up 70 percent of homeowners’ summer energy bills.

How Air Conditioners Work

Air conditioners work in a way similar to how your refrigerator works but on a larger scale. Air conditioners are closed loop systems that cool buildings through heat absorption. Warm air from the interior of the building is sucked in through a grille at the base of the inside air conditioning components. This air flows over evaporator coils through which a refrigerant circulates.

The air conditioner’s evaporator has reduced pressure on the refrigerant, allowing it to more easily convert into a gas. When the warm air passes over the evaporator coils, the refrigerant absorbs heat from that air. The cooled air is then blown throughout the building, while the refrigerant, now in vapor form, circulates back outside to the compressor.

The vaporized refrigerant releases its heat outside and passes over condenser coils, where it is cooled. The system’s compressor increases the pressure the vapor is under, thus converting it back into a liquid. The process then begins again, with the refrigerant flowing back into the building.

Why Clean AC Coils

Evaporator and condenser coils have a more difficult time doing their jobs if they are dirty. Each set of coils has a specific function to perform, and a build-up of dirt or grime can inhibit their effectiveness.

For evaporator coils, dirt and grime can result in an impaired ability to absorb heat and sufficiently cool the air. This can result in more energy use, as the unit must work harder to provide desired temperatures and increased wear and tear on the unit from higher pressures and temperatures. Dirty evaporator coils may also result in frost and ice buildup on the evaporator, which can damage the unit.

Even a thin layer of dust on the evaporator coil can impair its function, as dust may insulate the coils, keeping heat in and air away from the coils. Unclean coils may also develop tiny holes that allow the refrigerant to leak.

The consequences of having dirty condenser coils are similar to those of having dirty evaporator coils. Dirty condenser coils will be less effective at converting vapor back into liquid and may result in excess moisture that can cause corrosion and affect the longevity of the unit.

Air conditioner technicians clean condenser coils by shutting off power to the outside unit, removing the top of the unit or an access panel and using brushes, spray, and specialized tools to remove dirt or grime from the coils and the unit. Evaporator coils are cleaned by turning off the power to the air conditioner, opening the access panel and using specialized cleaners and tools to clean the coils, similar to how condenser coils are cleaned outside.

In general, central heat and air conditioners are expected to last 10 to 30 years, with 20 being around average (units located in hot areas of the country where they will see more use, such as Florida or Arizona, typically last less than 20 years).

Most homeowners report spending between $3,612 and $7,134 on new air conditioning units, according to HomeAdvisor, so prolonging the life of your air conditioner unit through good maintenance is an excellent investment of your time and money.

Other AC Maintenance Tips

While cleaning your air conditioner coils is an important maintenance task, there are a number of other ways you can maintain your air conditioner, improving its efficiency and longevity.

  • One of the easiest and most effective maintenance tasks you can do to improve the efficiency of your air conditioner is regularly replacing the filters in your air conditioner. Clogged filters impair airflow and have a huge negative impact on a unit’s efficiency. Clogged filters can also impact the air conditioner’s coils. When normal airflow through an air conditioning system is obstructed, air that bypasses the filter can transport dirt into the evaporator coil and reduce its ability to absorb heat.
  • Air conditioning experts recommend changing air filters once a month during the summer months. In homes located in dusty areas or that have fur-shedding pets in the house, more frequent changes may be necessary.
  • Keeping the outside unit clear of vegetation and debris will also help to improve its efficiency and prolong its useful life. Over time, leaves, twigs, grass clippings, and other debris can build up on the outside of the unit and may reduce airflow.
  • Once per year, you should clean the outside of the unit and trim or cut away any vegetation growing near the unit. To clean the outside unit, cut the power to the unit and use a garden hose to wash out debris. The water flow should be gentle so you do not damage the unit.
  • Inspecting your thermostat can help ensure your air conditioner is working properly. Compare the temperature on the thermostat with another thermometer to ensure it is accurate. If the temperature appears to be off, you may need to replace the thermostat. Installing a new programmable thermostat can help you save on power, giving you greater control of when and how often the unit runs.
  • Regular maintenance visits by trained professionals can also help ensure that your unit is running properly and that any maintenance issues are identified and resolved. Professional air conditioner maintenance technicians and air duct cleaning services can perform a number of specialized maintenance tasks that do-it-yourselfers just don’t have the tools or training to perform. Their professional experience also gives them the insight needed to detect developing problems and mitigate them before they can become major expenses.