What’s both central to the HVAC system and a large consumer of energy costs for your facility? The Air Handling Unit (or AHU). Air Handling Units condition and circulate air in a building or facility as part of the heating, ventilating, and air-conditioning (HVAC) system. AHUs work hard and constantly to maintain a comfortable building environment. If the building is to remain comfortable, the air handlers need to operate without issue. We frequently see AHUs that are 25-50+ years old, are still in service and don’t always run as well as they did at the beginning of their life, making AHU refurbishment a much needed step to ensure your facility functions normally and doesn't waste unnecessary energy -- or money.
The typical lifespan of an Air Handling Unit is considered to be 20 to 25 years. Many times, the AHU labors away out of sight in a mechanical room. As long as it is still operating and producing air flow however, facility managers defer replacement. Replacing an AHU is a relatively large capital expense.
AHU performance typically deteriorates over the years and the space it serves is therefore unevenly and poorly conditioned. After a while however, there’s often general acceptance of poor temperature control and poor ventilation as being “just the way it is.” We also often find that space use has significantly changed over the life of the AHU and modern controls can reduce the energy use by tracking space occupancy and reducing air flow and conditioning of outside air. While we can now make AHUs run much more efficiently, they didn’t start that way.
AHUs were invented as part of the development of the complete HVAC system. Although various methods of cooling, from evaporation to using tons of ice were employed in an attempt to cool down spaces, it wasn’t until the twentieth century that HVAC systems, as they are known today, were invented.
It’s not clear exactly when the “first” AHU was created. But between the introduction of air conditioning in the early 1900s and the refinement of this technology in the 1930s-1950s, air handlers were developed, improved upon and finalized as the models found in buildings today.
The energy savings available when upgrading air handlers, coupled with utility incentives, make it cost effective to redesign and refurbish the AHU as an alternative to a complete replacement. The process also greatly improves the comfort level of the space.
AHU refurbishment or retrofitting typically includes:
With these improvements, it is not uncommon to reduce the energy use of the AHU by 40% or more and extend its life by 15-20 years.