How MVHR Helps Developers Meet Part L Requirements Without Complex Heating Upgrades

Part L of the Building Regulations sets strict targets for carbon emissions and fabric performance. Many developers think this means investing in expensive heating upgrades like underfloor systems or heat pumps.

But across Hampshire, Berkshire and Surrey, forward-thinking developers are using MVHR (Mechanical Ventilation with Heat Recovery) to improve compliance without altering their core heating strategy.

This blog shows how MVHR supports energy performance, lowers carbon impact, and avoids costly design changes.

What Part L requires from new builds

As of the 2021 update, Building Regulations Part L demands:

• Lower Dwelling Emission Rates (DER)
• Improved building fabric (U-values and air tightness)
• Greater reliance on SAP-approved technologies
• Reduced primary energy use

For commercial builds, SBEM models are used to show similar outcomes. Either way, MVHR can support both fabric and energy targets.

How MVHR contributes to Part L compliance

MVHR improves your score by:

• Capturing and reusing up to 90 percent of heat from stale air
• Reducing the load on heating systems
• Maintaining consistent indoor temperatures and air quality
• Supporting better air change control for airtight buildings
• Providing SAP and SBEM credits when correctly specified

Developers in Farnham and Reading have avoided system redesigns by adding MVHR to enhance their SAP outputs.

Real project examples

Guildford townhouses (Completed April 2024)

The client used MVHR in all 16 units to maintain SAP compliance while retaining conventional heating. ClimateWorks designed systems with over 85 percent heat recovery, helping achieve required EPC ratings without heat pump retrofits.

Andover flats (Ongoing)

A six-storey block with tight acoustic constraints was fitted with ducted MVHR systems that reduced heating load. SBEM reports confirmed Part L targets were met without changes to insulation or windows.

Wokingham affordable housing (Q4 2023)

Using MVHR helped the developer meet DER requirements without adding photovoltaic panels. This avoided planning objections and preserved the façade design.

Developer endorsements

“We didn’t want to commit to heat pumps for every unit. MVHR helped us hit the numbers with our existing plan.”
Developer, Guildford (2024)

“The ventilation spec made the SAP assessor’s job easier. No resubmissions, no hold-ups.”
Project Lead, Wokingham (2023)

Other benefits for developers

• Avoid late-stage specification changes that delay M&E design
• Improve EPC scores to aid marketability and funding access
• Support Net Zero reporting and ESG goals
• Reduce overheating complaints in sealed apartments
• Gain full F-Gas and commissioning compliance at PC

On a Winchester project in March 2024, ClimateWorks delivered pre-populated commissioning packs that saved the client’s technical team two weeks at handover.

When to involve your MVHR partner

To benefit from this approach:

• Involve your supplier at RIBA Stage 3 to finalise layout
• Coordinate early with SAP or SBEM assessors
• Confirm duct routes and grille sizes in technical design
• Include system specs in planning packs to reduce risk
• Review aftercare and maintenance access from day one

We support projects in Oxford, Petersfield, Newbury and beyond to deliver compliance and quality at every stage.

Why developers choose ClimateWorks

• Proven record of improving SAP and SBEM performance
• Systems that work with your existing heating strategy
• Drawings and duct layouts for planning and coordination
• Full commissioning and F-Gas tracking
• Document packs for handover and Part L submission

We help you meet the regs without changing your whole M&E plan.

About the author

Dr. Julian Carter
Thermal Systems Expert and Technical Advisor at ClimateWorks

Dr. Julian Carter is a highly experienced thermal systems expert with over 15 years in the field, holding a PhD in thermal systems. His career spans academic research, consulting and teaching, focusing on air conditioning and refrigeration systems. Dr. Carter bridges the gap between theoretical advancements and practical applications, providing expert insights to organisations like ClimateWorks, where his guidance informs decision-making and industry best practices. Notably, he has worked on international projects with organisations such as Daikin Industries, the International Institute of Refrigeration (IIR), and the United Nations Environment Programme (UNEP). Currently a lecturer at Edinburgh University, Dr. Carter combines his expertise with a passion for educating the next generation of engineers and advancing climate control technologies.

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