The air-handling unit (AHU) is a critical part of an HVAC system that circulates and conditions the air within a building. Over time, AHUs can experience wear and tear, resulting in decreased performance, higher energy consumption, and potential indoor air quality issues. Recognising the signs that your AHU needs refurbishment is essential for maintaining a comfortable and efficient indoor environment. In this blog post, we will discuss five common indicators that suggest it’s time to consider refurbishing your AHU.

Decreased Performance

One key sign that your AHU requires refurbishment is a noticeable decline in performance. If you experience inconsistent airflow, uneven temperatures throughout the building, or difficulty in maintaining comfort, it may be due to worn-out components or outdated technology in the AHU. Upgrading or replacing critical elements such as fans, motors, coils, and controls during the refurbishment process can help restore its performance.

Unusual Noises

Unusual or excessive noise coming from your AHU is another indication that refurbishment may be necessary. Rattling, banging, screeching, or other abnormal sounds could be caused by loose or worn-out components, damaged bearings, or imbalanced fan blades. These noises not only indicate potential mechanical issues but can also disrupt occupants and affect their comfort. A thorough inspection during refurbishment can identify and address these noise-related problems.

Increased Energy Consumption

A sudden increase in energy consumption without any changes in occupancy or usage patterns might be a sign that your AHU is operating inefficiently. Aging components, outdated controls, and inefficient fan systems can contribute to higher energy usage. Refurbishing the AHU presents an opportunity to upgrade to energy-efficient motors, install variable frequency drives (VFDs) for fan speed control, and implement advanced control strategies to optimise energy usage, leading to long-term energy savings.

Poor Indoor Air-Quality

The AHU plays a critical role in maintaining indoor air quality (IAQ) by filtering and conditioning the air before distributing it throughout the building. If occupants experience more allergies, respiratory issues, or a decline in air quality, it could be due to a compromised AHU. Over time, filters can become clogged, moisture can accumulate, and microbial growth can occur, resulting in poor IAQ. Refurbishing the AHU involves inspecting and replacing filters, cleaning coils, and addressing underlying issues to ensure a healthier and more comfortable environment.

Age & Lack of Maintenance

Lastly, the age of your AHU and its maintenance history are crucial factors in determining if refurbishment is necessary. Older AHUs that have not received proper maintenance are more prone to performance issues and inefficiencies. Even without specific signs, it’s advisable to consider refurbishing older AHUs to improve their reliability, performance, and energy efficiency. Regular maintenance and inspections can help identify potential issues early on, preventing costly breakdowns or replacements.


Recognising the signs that your AHU needs refurbishment is vital for maintaining optimal indoor air quality, energy efficiency, and occupant comfort. If you observe decreased performance, unusual noises, increased energy consumption, poor IAQ, or have an aging AHU without regular maintenance, it’s time to consider refurbishing the unit. By addressing these issues through refurbishment, you can enhance the AHU’s performance, extend its lifespan, and ensure reliable operation, leading to a healthier and more comfortable indoor environment. Consult HVAC professionals to assess your AHU and plan the necessary refurbishment steps.