Standard packaged air handling units work perfectly well for straightforward applications. But when the building is unusual, the performance requirements are specific, or the physical constraints are tight, off-the-shelf equipment often means compromise. That’s where bespoke AHU design delivers real value.
We design and manufacture custom air handling units at our UK facility for clients across every sector. From a precision cooling system for an aerospace manufacturer in Derby to a flat-pack unit designed for challenging access at a retail complex in Epsom, every bespoke project starts with the same question: what does this specific building actually need?
When Bespoke Makes Sense
There are several situations where custom design is the right choice.
Non-standard plant room dimensions. Standard AHUs come in standard sizes. If your plant room is an awkward shape, has limited headroom, or has restricted access routes, a standard unit may not physically fit — or if it fits, it may not leave enough space for maintenance access. We design units to fit the available space, not the other way around.
Specific performance requirements. Some applications need precise temperature control, particular humidity ranges, enhanced filtration, or unusual airflow configurations that standard units don’t offer. Our Heathrow project required a bespoke unit engineered to the exact operational specifications of a live airport environment — no standard product could have met the brief.
Challenging access. Getting a large AHU into an existing building can be the hardest part of the project. Narrow corridors, no crane access, upper-floor plant rooms with small lift shafts — all of these constraints favour a unit designed to be delivered in sections that can be manoeuvred through the available route and assembled on site. Our flat-pack approach for the Epsom retail installation solved exactly this problem.
Integration with existing systems. Replacement projects often need new AHUs that connect to existing ductwork, pipework, and controls without extensive modifications to the surrounding infrastructure. Bespoke design means we match the new unit to the existing connections rather than redesigning everything around a standard product.
Unusual environmental conditions. Corrosive atmospheres, extreme temperatures, high humidity, or hazardous environments may require specialist materials, coatings, or construction methods that standard units don’t offer.
Our Design Process
Every bespoke project follows a structured process.
Brief and survey. We start by understanding what you need — performance requirements, spatial constraints, environmental conditions, and any specific challenges. For replacement projects, we survey the existing installation to understand what we’re working with.
Concept design. Our engineering team develops an initial design concept addressing the brief. This includes unit configuration, component selection, materials specification, and preliminary sizing. We share this with you for review before committing to detailed design.
Detailed design. Once the concept is agreed, we develop full manufacturing drawings, performance calculations, and specifications. Everything is modelled before manufacture — airflow, pressure drop, heat transfer, noise levels — so the finished unit performs as intended.
Manufacture. We build every bespoke unit at our UK manufacturing facility. In-house production means quality control at every stage, from casing fabrication through to final assembly and factory testing.
Delivery and support. We coordinate delivery logistics and provide installation support through our Electroair division. Commissioning support ensures the installed unit performs as designed.
Bespoke vs Packaged: The Cost Question
Custom AHUs cost more than standard packaged units. That’s a fact. But the comparison isn’t always straightforward.
A standard unit that doesn’t quite fit the space may require building modifications to accommodate it — structural work, ductwork adaptations, additional access provisions. These costs often exceed the premium for a bespoke unit designed to fit perfectly.
A standard unit that doesn’t quite meet the performance requirements may need additional equipment downstream — supplementary heating, external filtration modules, acoustic enclosures. Again, the total system cost can exceed a bespoke solution that integrates everything into a single optimised unit.
And a standard unit that’s oversized because the right size doesn’t exist in the range wastes energy for its entire operating life. Over 20 years, that efficiency penalty dwarfs the initial cost difference.
We always give clients an honest comparison. If a standard unit genuinely meets the requirements, we’ll say so. When bespoke design delivers better value, we’ll explain why.
What We’ve Delivered
Our project portfolio demonstrates the range of bespoke solutions we’ve delivered. From precision-controlled units for the aerospace sector to high-capacity systems for major airports, every project showcases our ability to engineer solutions that standard products can’t match.
Each project page includes the brief, the solution, and the outcome — real evidence of our bespoke design capability.
Let’s Talk About Your Project
If you’ve got a project where standard AHUs don’t quite fit the bill — physically, technically, or practically — get in touch. We’ll discuss your requirements, assess whether bespoke design is the right approach, and if it is, show you how we’d solve it.
