Solving complex ventilation challenges with bespoke AHUs

29/09/2026

Solving complex ventilation challenges with bespoke AHUs

No two ventilation projects are exactly the same. Buildings vary in size, layout, and purpose. Available plant space differs dramatically. And there is huge variability in access restrictions, performance requirements, and client specifications.

Despite this, standard air handling units (AHU) designed around predetermined dimensions and configurations can still often provide everything required. But when a building presents a particularly unusual challenge, or clients have especially specific performance needs, bespoke AHUs might be the only feasible solution.

Challenges that influence AHU design

Several considerations have to be balanced for every successful AHU installation. Bespoke AHUs are normally a response to a small number of consistent challenges, including:

  • Restricted space. A refurbishment project, for example, may have very little available plant space. Existing walls, ductwork, and other building services can limit the dimensions of a new AHU.
  • Access limitations. If access routes are narrow, standard AHUs may be unable to be either delivered, positioned, or installed correctly.
  • Performance requirements. Airflow, heating, filtration, and extract requirements can all be specific to the building, with some environments demanding higher performance than standard AHUs deliver.

Air Vent Technology has a long history of designing and manufacturing bespoke AHU units that meet the performance, space, installation, and operational demands of clients across the UK. It’s from these decades of experience that we know bespoke design gives engineers greater freedom to balance any competing requirements.

Making an AHU fit a confined space

A previous AVT project demonstrates just how important this flexibility can be.

Our customer needed a supply AHU small enough to travel through the building, be installed inside an existing enclosed cupboard, and meet specified airflow, filtration, and heating requirements. The cupboard couldn’t be rebuilt or dismantled, creating strict limits on the dimensions of the unit.

Over a three-month period, we worked with the customer to refine the design. The eventual solution used a U-shaped airflow arrangement, with air travelling down through the unit and back up. This allowed the AHU to fit the available space while delivering the required 400l/s airflow and a 20°C temperature rise.

Planning extended beyond the AHU itself. Doors, corridors, and other potential obstacles were measured to confirm that the completed unit could reach its final position.

The result was a bespoke AHU that met the required performance specification within a highly restrictive space.

When the specification goes beyond performance

For another bespoke project, we supplied a colour-matched externally mounted AHU for a new biomethane production plant. The unit needed to provide tempered air, with a high-level extract fan supporting crossflow ventilation.

Its position on an elevated external platform meant custom sizing was required. The customer also wanted the equipment to maintain visual consistency with the rest of the plant.

Our expertise ensured the unit was manufactured in the exact RAL colour requested, using powder-coating capabilities to achieve the required finish.

From the initial site visit to delivery of the finished unit, the entire process took just two weeks. The completed AHU met its performance targets, fitted the designated space, and matched the customer’s required colour.

Bespoke AHUs: start the conversation early

Both projects highlight the value of involving an AHU manufacturer as soon as possible when unusual requirements are identified.

Early discussions allow engineers to understand the complete picture and consider requirements together rather than individually. Potential problems can also be identified and resolved before any equipment reaches site.

As bespoke AHUs continue to play an important role across refurbishment, retrofit, and new-build projects, the starting point is always the same: understanding what the project needs and designing the AHU accordingly.

If you’re working on a project where space, access, or unusual performance requirements are making AHU selection difficult, speak to our team about a bespoke solution. We’re always ready to help.

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