Why Early Coordination of MVHR and AC Systems Reduces Variations and Delays

Late-stage mechanical design is one of the biggest causes of installation delays and unexpected cost variations on residential and mixed-use projects.

For main contractors, architects, and consultants working across Hampshire, Berkshire, and Surrey, early coordination of mechanical ventilation with heat recovery (MVHR) and air conditioning systems is critical to staying on schedule and on budget.

At ClimateWorks, we support M&E integration from RIBA Stage 2 or 3, providing reliable duct planning, accurate sizing, and buildable layouts—before problems emerge on site. This blog explains how our early-stage input prevents rework, reduces risk, and protects architectural intent.

Common problems when mechanical design is left too late

When MVHR and air conditioning are not integrated early, projects face:

• Duct clashes with steel, joists, or lighting
• Grilles placed without coordination with joinery or ceiling design
• Condensate pipe runs requiring core drilling or boxing-in
• Oversized plant rooms from generic system allowances
• Last-minute redesigns to accommodate missed access or zoning needs

In a 2023 M&E coordination report by BSRIA, 68% of delays in residential fitouts were linked to poorly sequenced building services planning (source). Early input avoids this.

What early coordination includes

Our early involvement provides:

• RIBA Stage 3 ductwork layouts aligned to structure and lighting
• Plant sizing based on real room loads and ventilation needs
• Grille positioning coordinated with lighting and ceiling design
• Service routes that avoid clashes and preserve structure
• Advice on acoustic treatment and access zones

This ensures the architect’s plans, the structural layout, and the M&E intent all align before technical design begins.

Project examples with specific dates

Woking – Six-unit new build scheme (Q3 2023)

We were brought in at Stage 2 by a developer-led design team. By producing early MVHR and split AC layouts, we helped reduce ceiling build-up by 75mm and avoided structural clashes. No post-start variations were needed.

Winchester – High-end residential renovation (Jan–Apr 2024)

Working alongside an architectural firm from Guildford, we redesigned the initial mechanical proposal that had not accounted for preserved ceiling roses and cornices. Early grille coordination enabled a compliant system that preserved all listed finishes.

Reading – Student housing retrofit (ongoing, 2024–2025 phase)

ClimateWorks engaged during pre-construction to zone MVHR units across floors with minimal risers. This avoided extending corridor service zones and helped the contractor meet tight build schedules for summer intake.

Endorsements from architects and contractors

“We’ve worked with ClimateWorks across multiple residential and commercial projects. Their early involvement always makes a difference. They’re able to coordinate mechanical systems with lighting, joinery, and structure at concept stage—avoiding the usual headaches.”
— Lead Architect, Guildford-based firm (2024)

“ClimateWorks delivered RIBA Stage 3 designs that our team could build from with zero rework. Everything from grille placement to acoustic zones was nailed from day one.”
— Project Manager, Hampshire main contractor (2023)

Benefits of early MVHR and AC design

By working with us before technical design freezes, you get:

• No service clashes in key zones
• Systems that are buildable, accessible, and unobtrusive
• Faster planning and smoother approvals
• Better thermal and acoustic outcomes
• Fewer contractor variations and delays

As highlighted in Approved Document Part F, MVHR systems must now meet strict flow, access, and commissioning requirements. These are best delivered when planned early—not retrofitted after the structure is complete.

How to engage ClimateWorks early

• Include us at Stage 2 or 3—before layout drawings are frozen
• Let us review architectural and structural plans together
• Provide space planning details for accurate load and flow calculations
• Share client expectations for comfort and aesthetics

We return buildable layouts, grille plans, riser diagrams, and plant sizing that M&E consultants and installers can take forward.

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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