ASHRAE Study on the Benefits of Coil Cleaning

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• Restoration of the one air handler resulted in improvements that will lead to energy savings of up to $40,000 this year, in accordance with the results and assumptions of this study. (The coil is 30 years old, and its last cleaning was one year ago, so the coil was in a dirty state.)
• Restoring the air handler resulted in a decrease in the pressure drop across the coil, of approximately 14%. This has resulted in a corresponding increase in airflow. The result is that the fan is producing that much more work in the form of cooling.
• Restoring the air handler resulted in an increase of 19 tons to 22 tons.
• Restoring the air handler increased the thermal efficiency of the cooling coil 25% with respect to its ability to transfer its energy to its sensible loads.
• Restoring the air handler increased the thermal efficiency of the cooling coil 10% with respect to its ability to transfer its energy to its latent loads. (This is especially significant as it helps to cure the only IAQ-related complaint from building occupants, which was elevated humidity levels in certain interior locations.)
• Restoring the air handler will continue to save energy by decreasing the load on the chiller plant, and making the heat transfer of its loading more efficient.
• A significant increase in latent heat transfer ability of the coil in the range of 10%. This indicates the ability of this coil "after cleaning" to being able to provide for better building dehumidification capacity control by delivering sub-dew-point air temperatures across the cooling coil.
• Other “soft” positive results come out of cleaning and normal maintenance operations and its resultant energy savings and airflow increases.
• The HVAC systems are cleaner, and do not provide an environment for fungal, bacterial and microbial growth in their coils, duct and pipes. IAQ and the awareness of good IAQ are increased in the building, and the overall comfort and work effectiveness can be greatly enhanced. Overall tenant satisfaction with the building environment has been improved as evidenced by the property manager’s communications and positive feedback.

Source: American Society of Heating, Refrigerating and Air-Conditioning Engineering, Inc. (ASHRAE), Ross D. Montgomery, P.E. and Robert Baker. Study Verifies Coil Cleaning Saves Energy. ASHRAE Journal (November 2006).

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