As temperatures drop, energy use in commercial buildings rises sharply. According to the Carbon Trust, heating alone can account for over 50% of a commercial building’s total energy consumption during winter months. Yet much of this energy is wasted due to poor system performance, outdated controls, or overlooked maintenance.

Here, we explore where commercial buildings lose the most efficiency in winter, and what facility managers can do to stop it.

Overheating zones

One of the most common winter inefficiencies is overheating. Research from CIBSE shows many commercial spaces are heated well above recommended comfort levels, particularly in offices with poor zoning.

Common causes include:

  • Inadequate temperature controls
  • Heat gains from equipment and occupants not factored into settings
  • Lack of zone level monitoring

Overheating not only wastes energy but also reduces occupant comfort and productivity. Even a 1°C increase in internal temperature can raise heating energy use by up to 8%.

Misaligned BMS settings

Building Management Systems (BMS) are designed to improve efficiency, but only when correctly configured. Studies by the Carbon Trust indicate that poorly commissioned or outdated BMS settings are a major contributor to winter energy waste.

Issues often include:

  • Heating running outside occupied hours
  • Simultaneous heating and cooling
  • Seasonal settings not adjusted for winter conditions

Regular commissioning and seasonal optimisation ensure systems respond to real building demand rather than outdated assumptions.

Poor Insulation on Pipework

Uninsulated or poorly insulated pipework is a silent energy drainer. The Energy Saving Trust estimates that insulating hot water pipes can reduce heat loss by up to 75%.

In commercial buildings, exposed pipework in plant rooms, ceiling voids, or risers can:

  • Increase boiler runtime
  • Cause uneven heating distribution
  • Raise overall energy costs

Proper insulation is a low-cost intervention with immediate efficiency gains.

Old or dirty filters

HVAC filters that are clogged or overdue for replacement restrict airflow, forcing systems to work harder to maintain temperature. According to HVAC efficiency studies, dirty filters can increase energy consumption by 5–15%.

Consequences include:

  • Reduced heat transfer efficiency
  • Higher fan energy use
  • Increased wear on system components

Routine maintenance keeps systems operating at peak efficiency throughout winter.

Inefficient boiler operation

Older boilers or poorly maintained systems often operate below optimal efficiency. The UK government’s building efficiency guidance highlights that modern condensing boilers can achieve efficiencies above 90%, while older systems may fall well short.

Common winter issues include:

  • Incorrect flow temperatures
  • Short cycling
  • Lack of weather compensation controls

Optimising boiler performance ensures heat is delivered efficiently, not expensively.

Unbalanced HVAC systems

An unbalanced HVAC system delivers too much heat to some areas and not enough to others. This imbalance often leads to occupants manually intervening by opening windows or using portable heaters, which further increases energy waste.

Balancing systems helps:

  • Ensure even heat distribution
  • Reduce unnecessary energy demand
  • Improve occupant comfort

Professional testing and balancing are key to resolving these inefficiencies.

Hybrid keeps the wasted energy to a minimum by identifying inefficiencies, optimising systems, and maintaining building performance year-round, Hybrid helps commercial buildings stay comfortable, compliant, and energy efficient, even in the depths of winter.