Unlocking Energy Efficiency: The Power of Retro-Commissioning HVAC Systems

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

One of the most effective strategies is retro-commissioning. This process systematically optimises existing HVAC and control systems, restoring them to peak performance—essentially returning them to the efficiency levels they had when first installed.

Instead of replacing older equipment, retro-commissioning fine-tunes what you already have. It identifies inefficiencies, corrects faults and settings, and ensures systems operate as originally intended.

For most commercial buildings, energy waste isn’t due to broken equipment; it’s because equipment runs inefficiently.

Why Older HVAC Systems Waste Energy

Over time, even well-maintained buildings drift away from their original performance. 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• Outdated or poorly maintained control strategies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, yet they drive up energy costs year after year. Businesses often sign off on higher utility bills without realising how much extra it costs them.

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

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 involve simple adjustments:

• Updating control sequences

• Correcting scheduling errors

• Rebalancing air and water systems

• Ensuring heat pumps operate effectively between heating and cooling

• Optimising free cooling, night purge, and plant sequencing

• Repairing minor leaks or AHU dampers

  
  

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

Retro-commissioning isn’t just restricted to HVAC systems. Lighting controls are often overlooked. Lights frequently remain on after hours because the lighting control system isn’t 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

  
  

This not only delays the need for major capital expenditure on replacement systems but also helps you get the best value from existing HVAC assets.

4. Improves Comfort While Reducing Complaints

Optimised controls lead to:

• Stabilised indoor temperatures

• More consistent airflows

• Fewer hot/cold spots

• Improved indoor air quality

  
  

This results in fewer reactive callouts and a more comfortable environment for building occupants.

5. Supports Carbon and Compliance Goals

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

• Reduced carbon emissions

• Improved EPC ratings

• Demonstrating measurable energy improvements

• Preparing 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

Many UK commercial buildings—especially those built between the 1980s and 2000s—are long overdue for 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.

We regularly see buildings still operating with their systems in manual mode (24/7) without any form of control after a BMS engineer's visit.

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

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

High energy costs make inaction increasingly expensive. 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" that can continuously monitor all systems and alert FM's, building operators, etc., when something isn't working as it should. This proactive approach allows for corrective action to be taken, reducing the impact on energy bills.