Clogged with Debris: a blocked condenser coil expels less heat, forcing the HVAC system to work harder and longer. Putting a higher load on your equipment and consuming more energy. Facility Managers looking to cut energy wastage and costs should make coil cleaning part of their PPM schedule. Here’s why.
Regular maintenance inline with AS/NZS 3.666  is vital to the proper functioning and longevity of any HVAC system. One aspect of preventive maintenance that may have been overlooked is coil cleaning. Dirty coils can lead to reduced system efficiency, higher energy costs, and even system failure. Here’s why coil cleaning is an essential aspect of preventive maintenance and how it can benefit HVAC systems.
LEFT, before Cleaning: Lack of air flow, poor comfort conditions, poor energy efficiency. RIGHT, after treatment: Increased air flow, improved comfort conditions and improved energy efficiency
HVAC coils are essential components of any air conditioning or refrigeration system. They are responsible for transferring heat between the air or refrigerant and the coil's surface. HVAC coils come in two types: evaporator coils and condenser coils. The evaporator coils are located inside the air handler unit and remove heat and humidity from the air, while the condenser coils are located outside and transfer heat from the refrigerant to the outdoor air.
Why is Coil Cleaning So Important?
Over time, dirt, dust, and other contaminants can accumulate on the surface of HVAC coils. This accumulation reduces the coil's heat transfer efficiency, making the system work harder and consume more energy. Dirty coils can also lead to increased compressor failure and reduced system life span.
In addition, dirty coils can negatively impact indoor air quality. When coils become contaminated with mould or bacteria, they can release these contaminants (including mycotoxins, toxic compounds that are naturally produced by certain types of moulds ) into the air, which can lead to health issues for building occupants. According to the EPA, "Indoor air pollution is among the top five environmental health risks" . Regular coil cleaning is necessary to maintain good indoor air quality and prevent the growth and spread of harmful pollutants.
“Cleaning HVAC coils is a great, proactive way to optimise energy efficiency, maintain cooling capacity, improve indoor air quality, and extend equipment life."
"In a chiller plant, when coils are blocked, cooling capacity of the system decreases and the compressor needs to run for longer durations or operate at higher pressures to maintain the desired temperature setpoint. This increased workload on the compressor results in higher energy consumption leading to higher energy bills.”
Dave Muldoon, INDOOR AIR QUALITY EXPERT AT CLEAN-AIR
How is Coil Cleaning Done?
Coil cleaning involves removing the buildup of dirt, dust, and other contaminants from the surface of the coils and forms part of a mechanical plant maintenance program. The process typically involves using specialised chemicals, sprayers, and brushes to loosen and remove the contaminants. An enzyme-based, non-corrosive cleaner and surface preparation product will be best suited for evaporator coils. The product is applied to cooling and heating coils in situ, and will remove bacteria, fungi and other contaminants. Specific products, such as AerisGuard HVAC Coil Cleaner, have been proven to improve efficiency of units by up to 54% , dramatically lowering load requirements and saving on energy expenditure.
AerisGuard HVAC Coil Cleaner has been proven to improve efficiency of units by up to 54%.
The process must be done carefully to avoid damaging the coils, and it is essential to use appropriate personal protective equipment (PPE) to avoid exposure to the contaminants. In addition to the cleaning process, a further step would be to apply a corrosion protection, a resilient coating which is sprayed over the coil to reduce corrosion and prolong the life of the unit.
Benefits of Coil Cleaning
The benefits of coil cleaning are many. A few of the most significant benefits include:
- Improved Energy Efficiency: Clean coils improve the system's efficiency, leading to reduced energy costs and improved performance.
- Extended System Life: Proper coil maintenance can extend the lifespan of the system and reduce the need for expensive repairs or replacements.
- Improved Indoor Air Quality: Coil cleaning removes contaminants that can lead to poor indoor air quality and the spread of harmful pollutants.
Energy Efficiency: Dirty condenser and evaporative coils have a negative impact on energy efficient HVAC system operation. According to the US Department of Energy (DOE) “a dirty condenser coil can increase compressor energy consumption by 30%”. A dirty evaporative coil will decrease airflow which reduces heat transfer thereby degrading the dehumidification process. 
Coil cleaning is an essential aspect of preventive maintenance for any HVAC system. Dirty coils can lead to reduced system efficiency, higher energy costs, and even system failure. Regular coil cleaning can improve energy efficiency, extend system life, and improve indoor air quality. Building owners and operators should make sure to include coil cleaning in their HVAC maintenance plans to ensure optimal performance and reduce energy consumption.
 AS/NZS 3666 is a series of standards that provide guidelines for the maintenance and performance of heating, ventilating, and air conditioning (HVAC) systems in non-residential buildings. The standards are divided into four parts, each covering a specific aspect of HVAC system maintenance and performance, including air handling and water treatment systems, ductwork, and microbial control. The AS/NZS 3666 standards provide recommendations for the design, installation, operation, and maintenance of HVAC systems to ensure they perform efficiently and effectively while minimising risks to building occupants and the environment. Adhering to these standards helps building owners and operators maintain high indoor air quality and minimise energy consumption while extending the life of their HVAC systems. More info https://cleanairaust.com.au/news/hvac-maintenance-obligations/  WHO. (2018, May 9) https://www.who.int/news-room/fact-sheets/detail/mycotoxins  EPA. (2019, June 12). Indoor Air Quality. Retrieved from https://www.epa.gov/indoor-air-quality-iaq  https://aeris.com.au/wp-content/uploads/2022/08/Aeris-AG-ECC-AerisGuard-Multi-enzyme-HVAC-Coil-Cleaner-Info-Sheet.pdf  Sheppard, Robert. “Clean HVAC System Coils Save Energy” www.buildings.com/article-details/articleid/8282/title/clean-hvac-system-coils-save-energy.aspx https://www.environment.gov.au/system/files/energy/files/hvac-factsheet-cleaning-coils.pdf
Scheduled cleaning and maintenance of HVAC Coils and Ducting can limit the spread of allergens, dust mites, bacteria, mould VOCs, and pollen, and ensures that your HVAC system operates at peak performance. If you require expert HVAC Hygiene services contact the Clean-Air team today. Thanks for reading.