A study published earlier this year found that professional HVAC cleaning could reduce fan and blower energy consumption by up to 60 per cent, while increasing supply airflow by up to 46 per cent.
The research was conducted across diverse environmental conditions and represented the first large-scale analysis of HVAC cleaning as an energy-saving intervention.
Professor Mark Hernandez, an academic at the University of Colorado Boulder and one of the study’s authors, explained that the key question was whether cleaning the ducts actually contributed to energy savings.
He said: “And the answer is yes, [though] it’s dependent on how much dirt work you have – the more you have, the better the benefit.”
During the testing, the researchers revealed an unexpected benefit of operating a clean HVAC system: dramatically improved system stability.
A key component of modern HVAC systems’ sensor network is variable airflow valves (VAVs), which report to a central control system.
When the system is dirty, the VAVs constantly look for the correct position, repeatedly opening and closing as they struggle to maintain proper airflow.
Prof Hernandez said: “The dirty system had the VAVs opening and shutting, but after cleaning, they were all opening together, all closing together – it behaved like a symphony orchestra.”
The improved system stability has major positive impacts on both energy efficiency and occupant comfort, as VAV systems waste less energy overshooting and undershooting their targets when operating more smoothly, and maintain more consistent temperatures and ventilation rates.
A parallel study undertaken by Denver Public Schools examined the effect of duct cleaning on indoor air quality and respiratory exposures.
The Denver researchers selected four schools with the poorest ventilation performance – as measured by their air exchange rates – to evaluate how cleaning might improve both air quality and ventilation effectiveness.
Initial results showed troubling patterns, as many schools were completely shutting down their HVAC systems overnight to conserve energy. When these systems were restarted in the morning before students arrived, some classrooms experienced dramatic spikes in airborne pollutants as settled dust and contaminants were re-suspended.
The researchers hypothesised that proper cleaning would help address these pollution spikes, but have yet to quantify the exact magnitude of improvement.
However, the research indicated that regular HVAC cleaning could be a crucial and often overlooked tool in building decarbonisation strategies.
The researchers explained: “Unlike many energy efficiency upgrades that require substantial capital investment, duct cleaning is a relatively straightforward maintenance intervention.
“The benefits scale with system size – larger ductwork systems showed greater improvements in airflow after cleaning, while smaller systems benefited more from coil cleaning due to enhanced heat exchange efficiency.
“The emergence of affordable Internet of Things monitoring technology has made it possible to precisely measure these improvements, providing facility managers with concrete evidence of cleaning’s impact on system performance.”
According to market research firm Industry Today, the Australian market for energy-efficient HVAC systems was valued at approximately US$1.5 billion in 2024. It is projected to grow at a compound annual growth rate of 6.33 per cent over the next decade, reaching US$2.7 billion by 2033.
The strong growth is supported by national energy efficiency policies, rising electricity tariffs, increased consumer
environmental awareness, as well as commercial retrofitting, net-zero building goals, and the integration of smart technologies.
A recent example of modern, energy-efficient HVAC design in Australia is the nearly completed Sydney Fish Market at Blackwattle Bay. The energy efficiency efforts of this project rely on the precise control and optimisation provided by its HVAC system.
HVAC design was not merely a technical requirement, but a central element of the fish market’s sustainability strategy – energy-efficient mechanical and electrical systems were needed to support the project’s vision of reducing environmental impact while meeting the comfort, safety, and reliability standards expected of a high-profile public facility.
The main client objectives for the project involved designing a central cooling plant aimed at reducing carbon emissions while implementing an HVAC solution that achieves a 25 per cent reduction in carbon emissions and lowers energy consumption by 5 to 30 per cent compared to traditional systems.
Another key aim was to implement a system that could seamlessly integrate with advanced building management systems (BMS) for optimal monitoring and control.
More than 130 variable drives were supplied for the landmark project, selected for their energy efficiency, seamless BMS integration, durability, ease of installation and maintenance, and application-specific control.
The drives covered a wide range of plant and equipment, including water systems such as pumps for chilled water, condenser water, and cooling tower operations; and air systems such as supply, return, and exhaust fans to maintain optimal indoor environments.
The drives are connected to the central BMS, facilitating real-time monitoring, predictive maintenance, and precise operational control.
This setup maximises efficiency during partial loads and peak demands, reduces equipment wear, and extends the system’s lifespan.