Retro-Commissioning: The Smart, Energy-Saving Second Chance for UK Buildings

As energy prices rise and carbon-reduction targets tighten for UK landlords, building owners and facilities managers are under pressure to try to improve the efficiency of their existing HVAC assets.

Often overlooked and forgotten, one of the most effective — is in retro-commissioning: which the systematic optimisation of the existing HVAC and control systems to restore them back to peak performance - in other words the same as the day they were first installed and commissioned.

Rather than replacing older equipment, retro-commissioning fine-tunes what you already have, identifying inefficiencies, correcting any faults/settings, and ensuring systems operate only as they were originally intended to.

For most commercial buildings, energy waste isn’t caused by broken equipment — it’s caused by equipment running inefficiently.

Why Older HVAC Systems Waste Energy

Over time, even well-maintained buildings often drift away from their original performance. But are you aware?

Common issues include:

• Misaligned temperature and pressure set-points

• Sensors that have slipped out of calibration

• Fans, pumps, and chillers running longer than required

• Simultaneous heating and cooling

• Outdated or poorly maintained control strategies

• Airflow imbalances and unnoticed duct leaks

These issues rarely trigger alarms, but they drive up energy costs year after year. Businesses are often unaware and simply sign-off higher utility bills without realising how much extra its costing them.

Retro-commissioning uncovers and resolves these inefficiencies — often at surprisingly low cost.

The Energy-Saving benefit of Retro-Commissioning

1. Immediate Reduction in Energy Consumption

Retro-commissioning targets hidden inefficiencies. By re-tuning the BMS or HVAC controls, correcting drifted set-points, and eliminating unnecessary equipment operation, buildings can typically achieve:

10–30% reductions in HVAC energy consumption

For larger systems, this often translates into six-figure annual energy savings.

2. Low Cost, Fast Payback

Unlike equipment replacement, retro-commissioning focuses on optimisation rather than capital investment. Many improvements just involve some simple adjustments:

• Updating control sequences

• Correcting scheduling errors

• Rebalancing air and water systems

• Ensuring Heat Pumps are operating effectively between Heating/Cooling

• Optimising free cooling, night purge, and plant sequencing

• Repairing minor leaks or AHU dampers

Because these improvements are low-cost, the paybacks vary depending on the building systems type and size and often fall between 1 and 4 years.

These retro commissioning isnt just restricted to the HVAC system. Often overlooked are lighting controls. No wonder lights are often on out of hours because the lighting control system isnt operating as it should.

3. Extends the Life of Existing Plant

When equipment runs efficiently, it experiences:

• Less mechanical stress

• Fewer unnecessary hours of operation

• Lower risk of premature failure

It also delays the need for major capital expenditure on replacement systems and helps you benefit the best value from the existing HVAC assets.

4. Improves Comfort While Reducing Complaints

Optimised controls result in:

• Stabilised indoor temperatures

• More consistent airflows

• Fewer hot/cold spots

• Improved indoor air quality

This also then leads to less reactive callouts and a more comfortable environment for the buildings occupants.

5. Supports Carbon and Compliance Goals

With the tightening EPC performance standards for commercial buildings — including MEES, and operational energy reporting — retro-commissioning offers a practical and cost-effective route which include:

• Reduced carbon emissions

• Improved EPC ratings

• Demonstrate measurable energy improvements

• Prepare for net-zero carbon goals

It’s also one of the fastest ways to reduce a building’s operational footprint without needing any major refurbishment work.

Why Building Owners Should Act Now

For many UK commercial buildings — especially those built between the 1980s and 2000s — are long overdue an energy performance review. Even buildings with some form of BMS often suffer from years of adjustments, that have never been corrected, occupancy changes, and outdated programming.

Indeed we regularly see many buildings which are still operating with their systems operating in manual mode (24/7) without any form of control - following a BMS engineers visit.

To understand just how much extra it can cost a business, this Case Study by EnviroLogic sums the problem perfectly and highlights the additional cost (and therefore the immediate savings) to the client involved.

Retro-commissioning provides a second chance to unlock the original efficiency your building was originally designed to deliver.

High energy costs make inaction increasingly expensive. Whilst optimising existing HVAC systems remains one of the highest-value, lowest-cost interventions available.

A Practical Call to Action for UK Building Owners

If you own, operate, or manage a building, ask yourself:

• When was the last time your HVAC controls were formally reviewed?

• Are your systems still operating as they were originally designed?

• Are sensors, valves, dampers and actuators functioning correctly?

• Do your operating hours reflect today’s occupancy?

• Do you have evidence your plant is running efficiently?

If you can’t confidently answer “yes” to all of the above, your building is almost certainly using more energy than it should.

A retro-commissioning assessment can quickly identify improvement opportunities and quantify potential savings — giving you a clear business case for action.

In Conclusion - The Second-Best Time to

Re-Commission Your Building is Now.

Whether your building is 5 years old or 50 years old, retro-commissioning offers an immediate path to:

• Reduce energy consumption.

• Lower carbon emissions

• Cut operating costs

• Improve comfort

• Extend the life of your HVAC system

In an era of high energy costs and sustainability commitments, giving your building a performance reset isn’t just smart — it’s essential.

Never to be forgotten is the option to include an IoT "Virtual Engineer" which can continuously monitor all of the able systems and alert FM's, building operators etc that something is working when it shouldn't be so that corrective action can be taken to reduce the impact on the energy bill.