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Are Air Source Heat Pumps Noisy? What You Really Need to Know Before Installing
- Lindo Mavuso
- Sep 10
- 4 min read
So you're thinking about switching to an air source heat pump…
But there’s one question bouncing around your head louder than any compressor:
“Aren’t they noisy?”
Let’s get straight to the point: No, air source heat pumps are not loud. In fact, most of the time, you’ll barely notice it’s running.
And in this short guide, we’ll break down:
What kind of sound does a heat pump make
How loud they really are (in decibels, not guesses)
When they make noise (and when they don’t)
How to make yours as silent as possible
If noise has been holding you back from going green, consider this your myth-busting moment.
Already considering a switch? Learn more about our ultra-efficient systems here: Air Source Heat Pump Installation →
How Loud Is a Heat Pump in Real Life? (Measured in Decibels)
Let’s skip the vague opinions and get into hard numbers.
A typical air source heat pump outdoor unit produces between 40 and 50 decibels (dB) when running.
Here’s what that actually sounds like:
Sound Source | Decibel Level |
Whisper | 30 dB |
Modern Heat Pump | 40–50 dB |
Fridge (running) | 40–45 dB |
Conversation | 60 dB |
Gas Boiler (startup) | 70–80 dB |
So, unless your heat pump is running full blast during sub-zero temperatures, it’s not going to drown out your Netflix binge or keep the neighbours up at night.
In many cases, the soft hum from the outdoor unit is quieter than your existing combi boiler or even your kitchen fridge.
And if you're thinking about putting it near a window or shared boundary, don’t stress, UK planning rules already limit units to 37 dB at 1 metre from the nearest property line (at the assessment positions, ignoring the effect of the façade, so certified installers ensure MCS compliance automatically.
Want Peace of Mind?
At Puraflow Renewables, we use ultra-quiet R32 & R290 units from brands like Midea, Mitsubishi Electric, Vaillant, and Samsung, many of which include silent mode, smart controllers, and vibration-dampening mounts.
We also provide tailored placement guidance during our free home survey to ensure noise isn’t an issue — even for compact properties or terraced homes.
When Do Heat Pumps Make Noise (And When Are They Silent)?
Let’s break it down, because heat pumps aren’t just on or off. Their sound levels change depending on how hard they’re working.
Here’s when you’ll notice them:
During Cold Spells
On freezing winter mornings (below 0°C), the unit works harder to extract heat from the air. That’s when the fan spins faster and the compressor kicks in at higher levels, but even then, it usually stays within 45–50 dB.
Still much quieter than a gas boiler during startup or radiators knocking around.
During the Defrost Cycle
Now and then, especially in frosty weather, your heat pump will enter defrost mode to clear ice from the external coil.
This lasts 5–10 minutes, and you might hear a brief uptick in sound (fan noise + soft whoosh). Totally normal. Completely automatic.
When It’s Not Working Hard? Practically Silent
On mild days or when your home is already warm, your heat pump ramps down and becomes whisper-quiet.
The indoor unit? It’s just a small circulation pump and valve, usually no louder than a ticking watch.
Concerned about placement or neighbours? During our free home survey, we’ll assess wall positions, spacing, and orientation to make sure noise is a non-issue, especially if you live in a terrace or semi-detached.
How to Make Your Heat Pump as Quiet as Possible
Even though most modern heat pumps are already quiet, a smart install can make them virtually silent.
Here’s how we do it at Puraflow Renewables, and how you can make sure noise is a non-issue for years to come.
1. Choose the Right Location
This is the #1 factor in how noisy your unit will feel.
Ideal placement:
On a flat surface away from bedroom windows
On a rear or side wall (not under an open window)
With at least 1 metre clearance around the unit for airflow
Avoid corner placements or echo chambers between walls — they can amplify sound like a speaker box.
2. Use Wall Brackets or Acoustic Pads
If the unit is wall-mounted, use anti-vibration brackets to isolate noise.
For ground-mounted systems, rubber isolation feet or slabs can reduce low-frequency hums.
We install all systems with vibration-reduction built in as standard.
3. Enable “Quiet Mode” (If Available)
Many premium systems from brands like Midea, Mitsubishi Electric, Vaillant, or Samsung include a low-noise mode.
This reduces fan speed during sensitive hours
Useful for night-time operation or densely populated areas
Ask us about quiet-optimised models during your initial consult.
4. Keep It Clean and Serviced
Dust, debris, and clogged filters can force the system to work harder, which increases sound.
Annual servicing keeps everything running smoothly and quietly.
At Puraflow, we offer ongoing support plans to ensure optimal performance and low-noise operation all year round.
Final Thought
Air source heat pumps aren’t just low-carbon and cost-efficient, they’re also whisper-quiet when installed correctly.
And with proper planning, most homeowners won’t hear anything louder than a soft breeze.
Ready to start your installation? Book your free home survey here →
Final Verdict: Are Air Source Heat Pumps Noisy?
No, not in any meaningful way.
Modern air source heat pumps are designed to run quietly, efficiently, and unobtrusively, even in cold UK winters.
With most units operating at 40–50 decibels, you’ll rarely hear more than a soft hum outside your window.
And with smart placement, vibration isolation, and silent mode enabled?
Your new heating system could be quieter than your fridge, while saving you hundreds a year and cutting your carbon footprint.
Ready to Install an Ultra-Quiet Heat Pump?
At Puraflow Renewables, we design and install whisper-quiet systems across the UK, with full support, grant guidance, and ongoing maintenance.
No guesswork. No noise. Just clean, quiet heating, done right.
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