How to Avoid Grille and Duct Conflicts in AC and MVHR Installations: Guidance for Architects and Main Contractors

Grille and duct clashes delay projects, frustrate site teams, and reduce system performance. These issues are preventable when air conditioning and MVHR partners are involved early and contribute to the layout.

Across Hampshire, Berkshire and Surrey, architects and contractors are finding success when grilles are coordinated properly with lighting, beams and ceiling zones. This blog shows you how to avoid unnecessary change orders and maintain design intent.

Common grille and ductwork problems on site

Projects across Newbury, Reading and Guildford regularly face:

• Grilles installed too close to light fittings
• Ducts clashing with beams or steelwork
• Ceiling features blocking airflow
• Joinery or bulkheads obscuring terminal positions
• Visual misalignment with architectural details

Each problem leads to either rework or system underperformance. In many flats across a Petersfield site in 2023, poor grille placement caused both overheating and inconsistent airflow.

Why these conflicts happen

The root causes include:

• Grille layout omitted from reflected ceiling plans
• Contractors working from outdated ductwork drawings
• Lack of involvement from the system supplier at design stage
• Mechanical plans developed in isolation from architectural design
• No standard clearance zones agreed for ducts or terminals

On a commercial project in Woking during Spring 2024, the architect revised their design three times after grille clashes with lighting and partition details were discovered too late.

Case studies

Oxford apartment development (January 2024)

The architect planned a clean ceiling aesthetic with flush-mounted grilles. ClimateWorks reviewed lighting layouts and proposed coordinated grille spacing. No conflicts occurred during first fix or commissioning.

Winchester commercial fit out (Completed February 2024)

By working with the structural engineer before slab approval, we aligned duct zones with soffit levels. The result was uninterrupted ceiling zones and zero acoustic complaints from tenants.

School extension in Andover (Summer 2023)

ClimateWorks held early layout workshops with the main contractor. Grille positions were confirmed before M&E issue, avoiding any site-level design changes.

Professional endorsements

“We avoided major disruption during install by finalising grille and duct positions before design freeze.”
Architect, Oxford (2024)

“They reviewed every zone with us and made sure ceiling layouts remained consistent from drawing to install.”
Contracts Manager, Winchester (2024)

Coordination best practices

To keep your project on track:

• Invite your air conditioning and MVHR partner to review RCPs before tender
• Share proposed grille layouts with electrical and architectural teams
• Identify zones where throw distances may conflict with fittings or partitions
• Confirm grille type and finish early to avoid visual mismatches
• Allocate a specific duct clearance zone above all grilles and diffusers

This ensures you protect both performance and appearance across every unit or space.

Regulatory guidance

Designers and contractors should follow:

• Building Regulations Part F for minimum airflow standards
• CIBSE Guide B for detailed ductwork and airflow coordination
• BS EN 13779 for non-residential ventilation design

These provide the framework for effective grille and duct placement.

Why ClimateWorks helps you avoid problems

We support clients from Guildford to Andover by:

• Reviewing duct and grille layouts before Stage 4
• Offering grille options to match architectural finishes
• Providing RCP-ready drawings for coordination
• Attending site walkthroughs to confirm installation paths
• Completing handover documentation for each zone

Every service we deliver is designed to prevent clashes and reduce site risk.

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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