Dirty Coils Cost You Money
Waiting to take action until you notice symptoms of dirty cooling coils increases your energy costs. Properties that have instituted annual coil cleaning programs have saved money—and the increased maintenance costs have had payback periods of less than one year.
As cooling coils age, they become less effective and their cooling capacities are diminished. This is caused by dirt build-up over time, which reduces heat transfer capabilities and limits air flow through the coil. As a result, compressors in direct expansion units must work harder, and chilled water units’ central capacity is limited and less efficient.
Four common symptoms of dirty coils are:
- Increased static pressure
- Decreased heat transfer
- Decreased indoor air quality
- Decreased compressor life
This partially cleaned air conditioning coil shows the degree of clogging that had been present (black area compared to the shiny silver).
A study reported in a recent American Society of Refrigeration and Air Conditioning Engineers (ASHRAE) Journal found that good maintenance and operation practices at a fairly large facility—including annual coil cleaning—resulted in a 10–15% overall energy savings, including the following:
- 14% reduction in air pressure drop across the coil
- 6% increase in cooling tons available to the facility at the central plant
- 25% increase in sensible thermal efficiency of the air handler
- 10% increase in latent thermal efficiency of the air handler
Coil cleaning should be included in your annual maintenance budget for all facilities. Locations near food service exhaust, construction sites or manufacturing facilities may require more frequent cleaning.