When an air handling unit can no longer perform reliably, the question is whether to refurbish it or replace it with a newly manufactured one. Both routes can deliver a high performing, energy efficient system. The right choice depends on the condition of the unit, the budget available, the disruption you can tolerate and your carbon goals. This article compares AHU refurbishment and new AHU manufacturing on cost, energy savings, downtime and sustainability.
Refurbishment and manufacturing in brief
AHU refurbishment restores an existing air handling unit to full working order through a targeted programme of repairs and upgrades: replacing fans, coils, filters and dampers, renewing panels and seals, upgrading controls and improving heat recovery. It typically extends working life by another 10 to 20 years and is carried out in situ. New manufacturing means designing and building a bespoke replacement, engineered to current standards and sized precisely for the building today. Manufacturing is the right answer when a unit is too corroded or damaged to recover, or when the building requirements have outgrown the existing unit.
Comparing the cost
Refurbishing an air handling unit in situ costs in the region of 40 per cent of the price of supplying and installing a new unit. The saving comes from retaining the existing casing and structure where it is sound, avoiding removal and disposal costs, and reducing the craneage and builder work that a full replacement often demands. New manufacturing carries a higher capital cost, but it is not money wasted when a unit is genuinely beyond economic repair.
Comparing the energy savings
The two routes are closer than many people expect, because the largest energy savings come from modern components that can be fitted during a refurbishment just as readily as in a new build:
- EC fans: upgrading to electronically commutated EC plug fans is the single most effective measure. They are markedly more efficient and quieter than belt driven fans, and can be retrofitted during refurbishment.
- Heat recovery: adding or upgrading a heat recovery device captures warmth from extract air and cuts the load on heating plant.
- Controls: modern AHU controls modulate fan speed, fresh air and heating in real time, one of the most cost effective efficiency measures available.
A refurbished unit can therefore achieve energy performance close to that of a newly manufactured one, at a fraction of the capital cost. A new unit holds an edge only where the original design itself is inefficient, for example where the unit is badly sized or the casing leaks heavily.
Downtime, disruption and carbon
Refurbishment usually wins on disruption. It can be phased and carried out in situ with little or no interruption, and avoids the long manufacturing and installation programme of a new unit. It is also the lower carbon option, retaining the embodied carbon in the existing structure while the efficiency upgrades cut operational carbon. Approved Document L of the Building Regulations continues to raise the bar for energy efficiency, and a well planned refurbishment helps existing buildings keep pace.
Which option is right for you?
Refurbishment is usually the better choice when the existing unit casing and structure are sound, the budget is limited, disruption must be kept low and carbon reduction matters. New manufacturing is the better choice when the unit is beyond economic repair or the building needs have outgrown it. The only reliable way to know which applies to your building is a professional survey.
Get a clear, costed recommendation
With over 40 years of experience, BVS offers both AHU refurbishment and bespoke AHU manufacturing, so our advice is genuinely impartial. We carry out detailed AHU validation and ventilation surveys, produce honest costed condition reports, and recommend the option that delivers the best value over the life of the asset. Contact the BVS team for an AHU survey and a clear recommendation.