One of the easiest, most cost-effective things than can be done in regards to energy efficiency is to have the HVAC system's condenser and evaporator coils inspected yearly and cleaned as necessary. Energy costs can be cut up to 30% with yearly cleanings. Costly service calls for frozen up units can be avoided with preventative cleaning to ensure the system is running at 100% efficiency. Clean coils affect energy efficiency, indoor air quality and longevity of the HVAC system.
In order to understand the negative impact dirty coils have on an HVAC unit, a quick description of their function and importance in maintaining a comfortable environment is detailed below:
An air-conditioning system has two coils, usually made of copper tubes with aluminum fins. The evaporator coil is the indoor coil and it's often described as the "cold" coil because it provides indoor cooling by absorbing heat blown across the fan. The condenser coil or outdoor coil is the "warm" coil as it rejects the heat as a fan blows outside air over it.
Although the evaporator coil is sheltered by an air filter (the condenser coil lacks this kind of protection), over time it still accumulates dirt. In addition, the evaporator coil and its condensate pan can become polluted with pollen, spores and other contaminants, all of which can have an undesirable effect on indoor air quality.
The condenser coil is exposed to the outside air and elements such as dust, dirt, leaves, grass clippings, animal fur, animal urine and more. While the condenser coil does not affect indoor air quality, cleaning it in conjunction with the evaporator coil will improve energy efficiency.
Accumulating dirt on coils inhibits heat transfer, forcing the compressor to work harder, increasing the temperature and head pressures as much as 75 percent as well as limiting the dehumidification process.
This results in increasing energy usage and utility costs while decreasing system life and occupant comfort. Dirty coils cause air quality in general to decline, motors to fail, as well as decrease the life expectancy of the entire unit. Additionally servicing dirty systems can lead to misdiagnosing problems and/or faulty or unnecessary repairs.
Having an annual coil cleaning can prevent malfunctions before severe degradation of the system or wasting significant amounts of energy. A coil cleaning program should be established when the coils are new and clean, and should be performed with enough frequency to prevent coil deterioration.