Mechanical Ventilation with Heat Recovery (MVHR) units can produce noise, but well-designed systems typically operate below UK Building Regulations Part F limits (30 dB in bedrooms, 35 dB in kitchens). Noise levels depend on unit quality, installation practices, and mitigation measures like anti-vibration mounts. Properly installed MVHR systems should maintain a quiet, comfortable indoor environment while ensuring efficient ventilation.
Understanding MVHR Noise in the UK: Design, Limits, and Mitigation
MVHR systems are essential for energy-efficient ventilation, but concerns about noise often arise. Here’s a detailed breakdown of how noise is managed under UK regulations and best practices.
1. Noise Limits Under UK Building Regulations
Building Regulations Part F sets clear acoustic standards for MVHR systems to protect occupant comfort:
- Bedrooms and living rooms: ≤ 30 dB LAeq,T (equivalent to a quiet library).
- Kitchens and bathrooms: ≤ 35 dB LAeq,T (similar to light rainfall).
These thresholds ensure systems don’t disrupt daily activities or sleep quality. While Part F doesn’t mandate formal noise testing, adherence to these guidelines is critical for compliance and occupant satisfaction.
2. Factors Influencing MVHR Noise Levels
a) Unit Design and Fan Speed
- Larger units at lower speeds: Generate less noise than smaller, high-speed models. For example, a 200 m³/hr unit running at 50% capacity is quieter than a 100 m³/hr unit at full capacity.
- DC vs. AC fans: DC fans (used in premium units like VENTI’s ARIA) adjust speed smoothly, reducing abrupt noise spikes.
b) Installation Best Practices
- Anti-vibration mounts: Prevent mechanical vibrations from transferring to the building structure.
- Ductwork layout: Minimise bends and rigid connections, which amplify airflow noise. Airtight seals at joints further reduce turbulence.
c) Component Quality
- Acoustic insulation: High-quality duct insulation absorbs sound.
- Heat exchanger type: Rotary exchangers (common in commercial systems) are noisier than counter-flow designs, which lack moving parts.
3. Noise Mitigation Strategies
| Strategy | Impact |
|---|---|
| Sound attenuators | Reduce inline noise by up to 15 dB when installed near vents or units. |
| Decentralised systems | Smaller, room-specific units (e.g., VENTI FLUXO) limit noise propagation. |
| Regular maintenance | Cleaning filters and fans prevents noise from dust buildup. |
Proactive design, such as placing the MVHR unit in a loft or garage, also isolates noise from living areas.
4. Real-World Noise Profiles
- Breakout noise: Measured 3m from the unit, should not exceed 45 dB (comparable to a refrigerator hum).
- Inline noise: At air valves (1–3m away), levels should stay below 25 dB in bedrooms, ensuring minimal disruption.
For context, 30 dB is quieter than a whisper, making well-installed MVHR systems virtually imperceptible during routine use.
Choose MVHR systems that balance efficiency with acoustic performance—consult experts like VENTI for tailored solutions that keep your home quiet and compliant.