Sound power vs sound pressure in heat pump design
When you’re speaking with homeowners about heat pumps, noise is rarely a technical question for them; it’s a practical one. They may ask questions like “Will I hear it in the garden?” or “Will it bother the neighbours?”.
So, before you get into system sizing or efficiency, you often end up addressing noise concerns in simple terms. This is where having a good understanding of the differences between sound power and sound pressure makes your job easier, as you’ll be able to answer the homeowner’s questions clearly and design the heat pump system correctly.
By carrying out detailed assessments and being able to present the results to your customer, you can help address some of their concerns.
Read more about:
What are the differences between sound pressure and sound power
Why these matter
Help prevent homeowner concerns before they happen
Sound assessments and calculations
Where support makes all the difference
What are the differences between sound pressure and sound power?
Sound pressure and sound power often get used as if they mean the same thing, but they don’t. Understanding the difference helps avoid confusion. Let’s break the two important definitions down:
Sound pressure level: the perceived ‘loudness’ of the heat pump from a certain distance from the source of the sound. It is what people hear once the heat pump is installed and running. This changes depending on where the heat pump is sited and is affected by everything around it, such as walls, windows or distances.
Sound power level: the loudness measured at the unit itself. This will also be included on the heat pump’s ErP label. The sound power doesn’t change no matter where you install it.
Why these matter
On paper, a heat pump can look perfect. The sound power rating is within spec, the unit is “quiet” and everything checks out during selection. But once it’s installed, real world scenarios come into play. Any potential noise concerns are based on perception, and sound pressure determines this.
Think about using sound power when:
Comparing different models
Checking specifications
Designing or selecting the heat pump at planning stage
Ensuring compliance or performance requirements are met
Think about using sound pressure when:
Deciding where a heat pump will be sited in line with MCS standards
Working on tight properties where placement options are limited
Fitting units near reflective surfaces like fences, walls or paving
