Noise Assessments for Air Source Heat Pumps (ASHP): Everything You Need to Know

Why Do I Need a Noise Assessment for My Air Source Heat Pump (ASHP)?

When installing an Air Source Heat Pump (ASHP), one of the key factors to consider is noise. ASHPs are efficient and eco-friendly, but their outdoor units can generate sound that may impact your neighbours and the surrounding environment. Understanding how to manage this noise and ensure your installation complies with local regulations is crucial. Here’s why a noise assessment is important.

There are two primary components in an ASHP that produce noise:

1. The Fan – This drives air over the evaporator coil

2. The Compressor – This compresses the refrigerant gas (often R12 or R410A)

Both of these components are housed in the outdoor unit, and the noise produced is a combination of two distinct sounds:

• Fan Noise: Created by the turbulent air flow.

• Compressor Noise: Generated by the mechanical processes involved in compressing the refrigerant.

Both of these sources radiate noise into the environment, and it’s essential to ensure that the combined noise level does not exceed the acceptable limits defined by local authorities.

How Is Noise Measured for ASHPs?

To determine the impact of noise from an ASHP installation, two primary methods are used in the UK: MSC20 and BS4142.

1. MSC20 (Micro-Site Compliance)

   The MSC20 method is a relatively straightforward approach that assumes a background noise level of 40dBA. However, this method is currently under review, and the process may soon become simpler. For some installations, the MSC20 can provide a quick way to assess compliance with noise regulations. Read more here.

2. BS4142:2014+A1:2019 (The Standard for Industrial Noise)

   The BS4142 standard is a more comprehensive and commonly used assessment method. It is specifically designed for noise impact assessments of industrial machinery, plant operations, and devices like air conditioners and heat pumps. The standard considers:

   • The specific noise level produced by the heat pump.

   • The background noise level at the nearest sensitive receptor (typically a bedroom or resting room in a neighbouring property).

   • How the noise from the ASHP compares to the background noise.

   Most local planning authorities (LPAs) in the UK rely on BS4142 to determine whether the noise from your ASHP will be permissible. They will often require that the ASHP noise level remains lower than the LA90 (the background noise level) by a specified margin, which can vary by location.

   Why Should You Consider Noise Impact Before Installation?

   Before purchasing an ASHP or an air conditioning unit, it is important to verify whether noise assessments are required by your LPA. The noise emissions of different units vary significantly, so it’s best to obtain a BS4142 noise assessment report before making a purchase decision. This way, you can ensure that the unit you choose will comply with local regulations and avoid unnecessary complications later.

   What Happens if Your ASHP Is Installed Without a Noise Assessment?

   Sometimes, local authorities will retrospectively request a noise assessment after installation, especially if complaints arise or if the system’s noise is detected to exceed the permitted levels. In these cases, you might be asked to take remedial actions. Common issues might include:

   • The noise level exceeds the allowable threshold.

   • The system was not properly assessed according to the local planning authority's guidelines.

   It’s essential to address these issues promptly. Avoid purchasing an acoustic cover or housing as a first solution. These can be costly (often over £1,500) and may not effectively resolve the noise problem. Instead, consider other, more cost-effective approaches to reduce the noise impact, such as repositioning the unit or installing noise-dampening materials.

   What to Do Next?

   If you are planning to install an ASHP, here are the next steps:

   1. Check Your Local Authority’s Website – Review the planning guidelines provided by your Local Planning Authority (LPA) to determine if a noise assessment is required.

   2. Obtain a BS4142 Noise Assessment – If required, ensure that the assessment is carried out before purchasing the unit. This will help avoid purchasing a unit that doesn’t meet noise compliance.

   3. Retrospective Noise Assessment – If the unit is already installed, but you’ve been asked for a noise assessment, do not panic. There are often solutions available to reduce noise levels or mitigate complaints, without the need for expensive acoustic covers.

   4. Contact Us for Support – If you're unsure about the process, or if you need a noise assessment, get in touch. We can guide you through the process and help ensure that your installation is compliant with local regulations.

   Why Choose Us for Your ASHP Noise Assessment?

   • Expertise: We specialize in noise assessments for ASHPs and other residential and industrial systems.

   • Efficiency: We ensure fast and accurate assessments to prevent delays in your project.

   • Cost-effective Solutions: We help you identify the best, most affordable options for noise mitigation.

   • Compliant Reports: Our assessments meet all regulatory standards to ensure you can proceed with your installation with peace of mind.

   Get in touch with us today at 01908 643 433, email or fill in the form to discuss your ASHP installation.