Heat Pump Noise: Guidance and Solutions
Air source heat pumps (ASHPs) are an increasingly popular choice for sustainable heating and cooling in residential and commercial properties. However, heat pump noise has emerged as a key concern, particularly in densely populated or rural areas.
Heat pump noise can affect neighbouring properties, which raises the importance of proper placement and noise assessments. While most installations fall under permitted development rights, certain conditions, such as proximity to other dwellings and local noise sensitivity, may require additional noise assessments to ensure compliance.
Limitations of the MCS020 Noise Assessment Method
The MCS020 standard provides a framework for assessing ASHP noise, yet it has notable limitations. In areas with very low background sound levels, often found in rural locations, the method may underestimate the likelihood of noise-related complaints.
In these quieter environments, even low levels of ‘heat pump noise’ can become intrusive, as there is minimal ambient sound to mask it. Consequently, installations that meet MCS020 criteria in urban settings may still fail to comply in rural areas. This highlights the need for a more nuanced approach to compliance in noise-sensitive environments.
When Our Services Are Essential
Our acoustic consultancy can provide crucial support in the following situations:
- For properties in rural or semi-rural areas where background noise levels are very low.
- When a proposed ASHP installation is near neighbouring properties, requiring detailed noise assessments in line with BS 4142.
- In cases where local authorities or Environmental Health Officers (EHOs) require noise impact assessments for planning or compliance purposes.
- When disputes arise between neighbours regarding ASHP noise.
We bring extensive experience in negotiating noise criteria with EHOs and can help navigate complex regulatory requirements.
Tips for Locating a New ASHP Unit
1. Assessing Location
For urban or suburban areas with higher ambient noise levels, installations are more likely to fall within permitted development rights. In rural areas, where background sound levels may be significantly lower, involving an acoustician is recommended to avoid potential non-compliance or disputes. A key crossover point is typically when background sound levels fall below 30 dB(A).
2. Understanding Tonality and Operational Patterns
Heat pump noise can often contain tonal sounds and may switch on and off frequently, increasing the potential for annoyance. These characteristics should be carefully considered during the site assessment and planning phases to ensure the unit does not create unnecessary disturbances.
3. Maximising Distance from Neighbours
To minimise the impact of heat pump noise, site the unit as far from neighbouring properties as possible. As a general rule, doubling the distance from the noise source reduces sound levels by approximately 6 dB due to point source propagation.
For example, moving a unit from 5 metres to 10 metres away from a neighbour can significantly reduce perceived noise.
4. Considering Reflections
Reflections from nearby surfaces, such as walls or fences, can amplify air source heat pump noise. This is quantified by the Q factor, which can range from 2 (minimal reflections) to 8 (significant reflections). Ensuring adequate space and strategic placement of the unit can help mitigate these effects.
5. Proper Installation
A poorly installed ASHP can generate excessive noise. Following the manufacturer’s installation guidelines is critical, particularly regarding levelling and securing the unit. Variations in installation can lead to higher operational noise and reduced efficiency.
Ground Source vs Air Source Heat Pump Noise
Ground source heat pumps (GSHPs) typically produce much less noise than ASHPs. Unlike ASHPs, which generate external noise from their fan and compressor units, GSHP noise is confined to the internal pump equipment housed within a building. This makes ‘heat pump noise’ a more significant concern for ASHPs, particularly in noise-sensitive environments. For those particularly concerned about noise, GSHPs may be a preferable alternative, although a large area of land is typically needed for their installation.
Checklist for ASHP Installation
- Location Assessment: Determine whether the area has low background noise levels that may require a professional acoustic assessment.
- Distance from Neighbours: Ensure the unit is placed as far from neighbouring properties as feasible.
- Use Existing Barriers: Having a barrier between the heat pump and a neighbouring property such as a shed can help to reduce noise levels.
- Minimise Reflections: Avoid placing the unit near reflective surfaces to reduce amplified noise.
- Consider Tonality: Account for the unit’s potential tonal noise and switching patterns.
- Follow Installation Guidelines: Adhere strictly to the manufacturer’s recommendations to avoid increased noise levels.
- Consult an Acoustician: For rural areas or challenging installations, seek professional advice to ensure compliance and minimise impact.
How We Can Help
We offer a tailored Noise Impact Assessment service to assist you in securing planning permission and have successfully worked with local authorities and EHOs to resolve noise issues for our clients. Our expertise ensures your ASHP installation meets all regulatory and community requirements while maintaining good neighbourly relations.
We can help with finding a suitable location for the unit, and advise if your heat pump will need to have noise control applied such as an enclosure and what performance that enclosure will need to have.
Contact us today for a free, no obligation fee proposal to assist with your air source heat pump noise control.