21/01/2026
| An insight from 4B's MEP Partner, Luke Mitchell.
Big Energy Saving Week is a useful moment to pause and reflect on where energy is actually consumed in our buildings, and where the biggest opportunities to reduce it truly sit.
Across most commercial and residential developments, MEP systems account for around 60–75% of total operational energy use. That alone makes MEP the single biggest lever available when improving energy performance.
That said, MEP doesn’t exist in isolation. Fabric performance, airtightness, internal heat gains and occupancy assumptions all set the level of demand that MEP systems are required to respond to. From an MEP surveying perspective, no amount of efficient plant can fully compensate for excessive demand that’s been locked in early.
This is why the early design stages matter so much.
By the end of RIBA Stages 2–3, most projects have already fixed their heating and cooling strategy, ventilation approach, plant sizing and spatial allowances. At that point, a significant proportion of a building’s lifetime energy cost has effectively been committed, often without the client fully realising it.
Too often, energy efficiency is discussed early but only properly scrutinised later during value engineering or construction. By then, opportunities to reduce demand have usually passed, and efficiency is what tends to be engineered out.
In reality, some of the most effective energy-saving measures are also the least complicated:
👉 Right-sizing of plant based on realistic thermal modelling
👉 Incorporating high-efficiency HVAC and heat recovery systems
👉 Designing low-temperature, electrified heating strategies
👉 Applying sensible zoning, controls and commissioning
When considered early, these measures can deliver meaningful reductions in operational energy with only modest capital impact.
One area still frequently overlooked is commissioning and post-occupancy tuning. Many buildings are still operating 15–20% above their intended energy use simply because systems aren’t set up or fine-tuned as designed.
In our experience, energy-efficient MEP strategies typically sit within a 2–4% uplift to MEP capital cost, with paybacks well within the life of the asset. The real risk to performance isn’t technology. It’s timing.
A thought I often come back to: While the end user experiences comfort at the flick of a switch, the performance behind this is the result of countless MEP designs and installation decisions.
Energy performance is not added at the end of a project. It is designed in early, shaped by informed decisions, and protected throughout delivery.
Big Energy Saving Week should be a reminder of that.
