Building Regulations & Part L Uplift: What It Means for Cooling and Ventilation

In 2022, the UK introduced the Part L uplift in the Building Regulations as part of its roadmap to net zero. While this update has mostly been discussed in the context of heating and insulation, it has big implications for air conditioning, evaporative cooling, and ventilation in commercial and industrial buildings. Fast-forward to 2025, and the effects are starting to be felt in real-world projects.

Why Part L Matters

Part L focuses on the conservation of fuel and power. In simple terms, it sets stricter targets for how buildings use energy. For cooling and ventilation, this means systems are expected to be more efficient than ever — not just in terms of equipment performance, but also how that equipment is designed, installed, and controlled.

For example, traditional comfort cooling may need to justify its energy demand against more efficient or passive options. Evaporative cooling and modern ventilation solutions are now seen as strong contenders because they can provide fresh air and temperature control at a fraction of the energy cost of conventional AC.

Design Choices Are Changing

Specifiers and facility managers are rethinking their approach. Instead of defaulting to mechanical cooling across the board, there’s a greater emphasis on mixed-mode strategies:

Evaporative cooling for large, open spaces such as warehouses and leisure facilities, where high airflow and reduced carbon output are a priority.
Mechanical ventilation with heat recovery (MVHR) to ensure fresh air without excessive energy loss.
Smart controls that fine-tune system operation, ensuring equipment only runs when conditions demand it.

These aren’t “nice to haves” anymore — they’re becoming necessary to meet compliance and avoid higher operational costs down the line.

The Bigger Picture

The Part L uplift is a stepping stone. With future tightening of standards expected, businesses that act now will avoid the scramble later. Choosing efficient cooling and ventilation doesn’t just tick a compliance box — it directly reduces running costs, supports employee wellbeing, and strengthens a company’s sustainability credentials.

At the same time, it’s worth noting that one size doesn’t fit all. The right mix of AC, ventilation, and evaporative cooling depends on building type, usage, and comfort requirements. But the trend is clear: energy efficiency is no longer optional.

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