To help our valued clients, we have produced The Ultimate MVHR Airflow Testing & Commissioning Guide. This will help clients navigate their MVHR Installation, Commissioning & Ventilation Testing for Part F Compliance.
If you’re installing a Mechanical Ventilation with Heat Recovery (MVHR) system, following a structured installation and testing process is essential. Poorly installed or incorrectly commissioned systems can fail Part F Building Regulations, suffer from excessive noise, poor airflow performance, occupant complaints, mould growth, and increased energy consumption.
This comprehensive MVHR guide and checklist is designed for:
- House builders
- Developers
- Main contractors
- Self-builders
- M&E contractors
- MVHR installers
- Building Control professionals
Part F MVHR Vent Test Checklist ▶
What is a MVHR System?
Mechanical Ventilation with Heat Recovery (MVHR) systems continuously extract stale air from wet rooms such as:
- Kitchens
- Bathrooms
- En-suites
- Utility rooms
The system simultaneously supplies filtered fresh air into:
- Living rooms
- Bedrooms
- Studies
- Home offices
Heat energy from the extracted air is recovered through a heat exchanger before being discharged externally, significantly improving energy efficiency while maintaining indoor air quality.
MVHR Pre-Installation Checklist
Before installation begins:
✅ Confirm ventilation design calculations completed
✅ Verify required airflow rates under Approved Document F
✅ Confirm unit size suitable for dwelling volume
✅ Check design drawings are available
✅ Verify intake and exhaust locations
✅ Ensure condensate drainage route identified
✅ Confirm electrical supply requirements
✅ Check accessibility for future maintenance
✅ Verify filter replacement access
✅ Review manufacturer installation instructions
✅ Confirm duct routes minimise bends and restrictions
✅ Ensure acoustic requirements considered
✅ Verify ceiling voids and service spaces are sufficient
MVHR Unit Installation Checklist
Unit Positioning
✅ Unit securely mounted
✅ Unit level
✅ Antivibration mounts fitted
✅ Maintenance access available
✅ Filters easily accessible
✅ Condensate drain installed
✅ Condensate trap fitted where required
✅ Frost protection measures installed if applicable
Electrical Installation
✅ Isolator provided
✅ Power supply connected
✅ Controls connected correctly
✅ Boost switches installed
✅ Humidity sensors connected (if specified)
✅ Commissioning controls accessible
Ductwork Installation Checklist
Poor ductwork installation is one of the most common causes of MVHR test failures.
Duct Routing
✅ Routes follow design drawings
✅ Duct runs kept as short as possible
✅ No unnecessary bends
✅ Flexible ducting minimised
✅ Correct duct diameters maintained
✅ Ductwork properly supported
✅ No crushed ductwork
✅ No sharp radius bends
Airtightness
✅ All joints sealed
✅ Connections taped correctly
✅ Manufacturer-approved sealants used
✅ Spigot connections sealed
✅ No visible air leakage
Insulation
✅ Cold-space ductwork insulated
✅ Intake duct insulated
✅ Exhaust duct insulated
✅ Vapour barriers intact
✅ No gaps in insulation
Valve & Grille Checklist
Supply Valves
✅ Installed in living rooms
✅ Installed in bedrooms
✅ Positioned away from occupants where possible
✅ Correct valve type fitted
✅ Valves unobstructed
Extract Valves
✅ Installed in kitchen
✅ Installed in bathrooms
✅ Installed in utility rooms
✅ Installed in WC areas
✅ Accessible for maintenance
✅ Correct extract locations achieved
External Terminal Checklist
✅ Intake and exhaust terminals installed
✅ Weather protection fitted
✅ Bird guards installed
✅ Correct separation distances maintained
✅ Terminals not blocked
✅ Access available for inspection
✅ Installed in accordance with manufacturer guidance
Pre-Commissioning MVHR Air Flow Checklist
Before airflow testing:
✅ Property substantially complete
✅ Internal doors fitted
✅ Windows installed
✅ Background ventilators installed where applicable
✅ Ductwork cleaned
✅ Filters installed
✅ All vents unobstructed
✅ Electrical supply energised
✅ Unit operational
✅ System balanced preliminarily
MVHR Commissioning Checklist
Part F requires systems to be commissioned to demonstrate compliance.
Airflow Testing
✅ Supply airflow rates measured
✅ Extract airflow rates measured
✅ Continuous rates recorded
✅ Boost rates recorded
✅ Whole dwelling ventilation rates verified
✅ Room-by-room measurements completed
✅ Results recorded
System Balancing
✅ Supply valves adjusted
✅ Extract valves adjusted
✅ Design airflow achieved
✅ Airflows balanced
✅ Pressure losses addressed
✅ Final settings recorded
MVHR Ventilation Testing Checklist
Independent MVHR Air Flow testing should verify:
Extract Ventilation Rates
✅ Kitchen extract rate achieved
✅ Bathroom extract rate achieved
✅ Utility room extract rate achieved
✅ WC extract rate achieved
Supply Ventilation Rates
✅ Living room supply rates achieved
✅ Bedroom supply rates achieved
✅ Home office supply rates achieved
Whole Dwelling Performance
✅ Overall system airflow verified
✅ Design rates achieved
✅ Part F compliance confirmed
✅ Test certificate issued
Common Reasons MVHR Systems Fail Testing
1. Incorrect Airflow Rates
Many systems are installed without proper balancing, causing airflow deficiencies.
2. Poor Ductwork Installation
Crushed or excessively long duct runs restrict airflow.
3. Air Leakage
Unsealed joints can dramatically reduce performance.
4. Dirty Filters
Construction dust frequently affects commissioning results.
5. Incorrect Valve Settings
Installers may accidentally alter balanced settings.
6. Undersized MVHR Units
The selected system may not meet dwelling airflow requirements.
7. Installation Deviations
Site changes often differ from original designs.
8. Blocked External Terminals
Debris and protective coverings are frequently overlooked.
9. Incomplete Construction
Testing before completion can produce invalid results.
10. Lack of Independent Verification
Independent testing helps identify issues before Building Control review.
Documentation Required for Building Control
Ensure the following documentation is available:
✅ Ventilation design calculations
✅ Manufacturer specifications
✅ Installation drawings
✅ Commissioning sheet
✅ Airflow test results
✅ User operating guide
✅ Maintenance instructions
✅ Part F Ventilation Test Certificate
✅ Handover documentation
Final MVHR Compliance Checklist
| Item | Complete |
|---|---|
| Design Calculations | □ |
| Unit Installed Correctly | □ |
| Ductwork Sealed | □ |
| Insulation Installed | □ |
| Valves Installed | □ |
| Electrical Connections Complete | □ |
| System Commissioned | □ |
| Airflows Balanced | □ |
| Ventilation Tested | □ |
| Part F Compliance Demonstrated | □ |
| Certificate Issued | □ |
Why Independent MVHR Testing Matters
Building Regulations require ventilation systems to provide adequate airflow and indoor air quality. Independent third-party MVHR Flow Rate Testing provides confidence that the system has been installed and commissioned correctly and delivers the performance specified in the design for compliance with Building Regulations Part F.
Early testing can identify installation issues before handover, avoiding costly remedial works and delays with Building Control sign-off.
Part F MVHR Vent Test Checklist ▶
About APT Sound Testing
APT Sound Testing Ltd provides nationwide MVHR testing, commissioning verification, Part F ventilation testing, air tightness testing, sound insulation testing and acoustic consultancy services for residential and commercial developments.
Our experienced engineers use calibrated equipment to verify ventilation system performance and assist developers, contractors and self-builders in achieving Building Regulations compliance.
Call: 01525 303905
Email: info@aptsoundtesting.co.uk
Website: https://www.aptsoundtesting.co.uk
Contact Us to Book Your MVHR Airflow Test
Need independent MVHR airflow testing or Part F ventilation testing?
Our team can provide fast turnaround testing appointments throughout the UK, helping you achieve Building Regulations compliance and avoid costly project delays.
📞 01525 303905
📧 info@aptsoundtesting.co.uk
🌐 https://www.aptsoundtesting.co.uk
