Are Heat Pumps Noisy? The Honest Answer
Noise is one of the biggest worries people have about heat pumps. The honest truth: modern units are genuinely quiet (40–60dB, less than a fridge) — and most complaints come from poor siting, not the pump.
The short answer
No — modern heat pumps are genuinely quiet, and noise is far less of a problem than people fear. A typical modern air source heat pump runs at 40–60 decibels at 1 metre — comparable to a domestic fridge, a quiet dishwasher, or steady rain, and quieter than a normal conversation. The latest 2026 units (especially R290 models) are 4–8dB quieter than a few years ago, and many carry Quiet Mark certification. Ground source heat pumps are quieter still — no outdoor unit at all.
The single most important fact: the vast majority of noise complaints come from poor installation and siting — not the heat pump itself. A fan pointed at a neighbour’s bedroom, a unit crammed too close to a boundary, or hard reflective surfaces cause nearly all real-world problems — and correct siting prevents them. In England, installations must pass a 37dB(A) noise limit at the nearest neighbour’s window (tightened from 42dB in May 2026) via the MCS 020 calculation. So: not silent, but genuinely quiet when chosen and fitted well. Full detail — the decibels, the rules, night noise and how to keep it quiet — below.
What this guide covers
“Are heat pumps noisy?” is one of the most common hesitations before switching from a gas boiler — and it’s a fair question, because a heat pump does have an outdoor fan, unlike a boiler. But the honest, evidence-based answer is reassuring: fitted properly, a modern heat pump is a quiet, unobtrusive machine. Here’s the full picture, including the bits some installers gloss over.
How loud are heat pumps really?
| Sound | Decibels (dB) |
|---|---|
| Whisper / quiet library | 30 |
| Domestic fridge | 40 |
| Quiet heat pump (R290, Quiet Mark) | 40–45 |
| Light rain / quiet office | 50 |
| Typical heat pump (at 1m) | 40–60 |
| Normal conversation | 60 |
| Dishwasher / washing machine | 60–70 |
As the table shows, a modern air source heat pump at 40–60dB(A) at 1 metre sits comfortably in “everyday quiet appliance” territory — the quietest models (R290 units, and Quiet Mark certified ones like the Vaillant aroTHERM Plus and Viessmann range) are around 40–45dB, on a par with a fridge. Two things to remember: decibels are logarithmic (a 10dB drop halves perceived loudness, so the newest units feel dramatically quieter than the numbers alone suggest), and these figures are measured right next to the unit — sound falls off sharply with distance, so several metres away at a neighbour’s boundary it’s typically below the background noise of a normal street. Indoor components (the hot water cylinder and controls) are near-silent — a faint fridge-like hum at most.
The UK neighbour noise limit (37dB — updated 2026)
Important 2026 update: the limit tightened from 42dB to 37dB
In England, air source heat pumps installed under permitted development (i.e. without a full planning application) must meet a strict noise limit at neighbouring homes. Here’s the current position — and note that many guides are out of date on this:
The limit is now 37.0 dB(A), measured 1 metre from the nearest neighbour’s habitable room window or door. This was tightened from the previous 42dB(A) on 28 May 2026, when MCS 020(a) became the only accepted certification route for permitted-development heat pump installs in England. If you see “42dB” quoted, it’s the old figure. Wales has similar rules (revised 1 June 2026), though details differ — Welsh homeowners should check Welsh Government guidance.
Your installer runs an MCS 020(a) noise calculation that predicts the sound reaching your neighbours, based on the unit’s sound power, position, distance, fan direction and any barriers. If it’s at or below 37dB(A) at every neighbour position, the install proceeds under permitted development — no planning application. If no siting can pass (which happens with tight terraces), you’d need full planning permission. Always ask for the MCS 020 workings before signing — it decides both compliance and whether your timeline is weeks or months. (This is the heat pump equivalent of solar’s planning rules, handled by any MCS-certified installer.)
Why siting matters more than the pump itself
This is the single most important thing to understand about heat pump noise: in the large majority of real-world noise complaints, the problem is poor siting and installation — not the heat pump. A perfectly quiet unit can become a nuisance if it’s installed badly. The common culprits: the fan facing directly at a neighbour’s (or your own) bedroom window; the unit crammed into a tight, enclosed corner where hard walls reflect and amplify the sound; positioning too close to a boundary; or a lack of anti-vibration mounts, letting the compressor transmit a low hum into the building structure. Get the siting right — fan pointed at open space away from windows, sensible clearance, vibration isolation, no reflective “sound trap” corners — and nearly all noise issues simply never arise. This is exactly why a proper survey matters: a good installer assesses noise and positioning before fitting, rather than bolting the unit to the nearest convenient wall. It’s also why choosing an experienced MCS-certified installer is worth more than obsessing over a model’s headline decibel figure.
Are heat pumps noisy at night?
Heat pumps run at broadly the same volume day and night, but they can feel more noticeable after dark simply because the background noise is quieter — the same 45dB unit that’s inaudible against daytime traffic may be just perceptible in the small hours. Two situations make a heat pump briefly louder, and both can happen at night: a defrost cycle (the unit reverses for a few minutes in cold weather to clear frost from the coil, giving a short whooshing sound), and a cold snap (the pump works harder, running the fan faster). Neither is loud, but both stand out when all else is silent. The fix is twofold: most modern units have a “night mode” / “quiet mode” that lowers the fan speed overnight (at a small cost to output), and — again — good siting (fan away from bedrooms, vibration isolation) makes it a non-issue. If night noise is a specific worry, raise it at the survey so the installer positions the unit and sets night mode accordingly.
How to keep a heat pump quiet
If you want the quietest possible outcome, these are the levers — most are about choice and installation, not luck:
- Choose a quiet model — look for a low sound-power figure and Quiet Mark certification (Vaillant, Viessmann and others do well here).
- Site it well — fan facing open space, away from bedroom windows (yours and neighbours’), 3+ metres from a neighbour boundary where possible.
- Insist on anti-vibration mounts — stops the compressor humming through the wall.
- Avoid enclosed, reflective corners — open space around the unit prevents sound build-up.
- Use an acoustic barrier if needed — a well-designed screen can cut perceived noise further (without blocking airflow).
- Enable night mode if the unit’s near a bedroom.
- Consider ground source — if noise is an absolute dealbreaker, a ground source heat pump has no outdoor unit and is effectively silent outside.
Do these — most of which a good installer handles as standard — and heat pump noise ceases to be a concern.
Frequently asked questions
Are heat pumps noisy?
No — modern units are genuinely quiet, running at 40–60dB at 1 metre (comparable to a fridge or quiet dishwasher, quieter than conversation). The latest R290 models are 4–8dB quieter still, and many are Quiet Mark certified. Ground source pumps are near-silent. Most noise complaints come from poor siting, not the pump.
How many decibels is a heat pump?
Typically 40–60dB(A) at 1 metre; the quietest models (R290, Quiet Mark) are ~40–45dB — about the same as a fridge. For context: fridge 40dB, light rain 50dB, conversation 60dB. Sound falls off with distance, so at a neighbour’s boundary it’s usually below background street noise. Look for a low sound-power figure when comparing models.
What’s the UK noise limit for heat pumps?
In England, 37.0 dB(A) at 1m from the nearest neighbour’s habitable window — tightened from 42dB on 28 May 2026 under MCS 020(a). (Older guides still say 42dB.) Your installer runs the MCS 020 calculation; passing it keeps the install permitted development. Wales has similar rules (from 1 June 2026). Ask for the workings before signing.
Are heat pumps noisy at night?
They run at the same volume, but feel more noticeable as background noise drops. They’re briefly louder during defrost cycles and cold snaps. Most units have a “night mode” that lowers fan speed overnight, and good siting (fan away from bedrooms, vibration isolation) makes it a non-issue. Raise night noise at the survey stage.
Can my neighbour complain about my heat pump?
Yes — if a heat pump causes a genuine noise nuisance, a neighbour can report it to the council’s Environmental Health team, who can investigate. But a properly sited unit passing the 37dB MCS 020 limit is very unlikely to cause issues. Most disputes stem from poor installation, which is why good siting and an MCS-certified installer matter. Talk to neighbours early if concerned.
Which heat pumps are the quietest?
Quiet Mark certified models lead — the Vaillant aroTHERM Plus and Viessmann units are among the quietest, and R290 (propane) heat pumps are generally quieter than older refrigerants. Ground source pumps are quietest of all (no outdoor unit). See our best heat pumps guide for quiet models, and check the sound-power figure on any quote.
The honest bottom line
Are heat pumps noisy? Not really — and certainly not the way the worry suggests. A modern air source heat pump runs at 40–60 decibels, no louder than a fridge or quiet dishwasher, and the newest 2026 models are quieter still. It isn’t silent — there’s an outdoor fan, and it’s briefly more audible during winter defrost cycles or at night when everything else is quiet — but “noisy” genuinely misrepresents the technology fitted well. The single biggest takeaway is that nearly all real noise problems come from poor siting, not the heat pump: get the positioning right and it’s a non-issue.
That’s exactly why the installer and the survey matter more than the headline decibel number. A good MCS-certified installer runs the MCS 020 noise calculation, positions the unit away from bedrooms with proper vibration isolation, and keeps you comfortably within the 37dB neighbour limit. If noise is on your mind, the best next step is to have an expert assess your specific home — a couple of free, no-obligation home surveys from MCS-certified installers will tell you exactly how quiet a heat pump would be at your property, and where it should go. For most homes, you’ll find noise is far less of a concern than you feared. (And if you’re still weighing it all up, see our honest are heat pumps worth it? guide.)
Important
Going Solar UK is an introduction service, not an installer. This guide gives general 2026 information on heat pump noise for research: actual noise levels depend on the specific model, its siting, your property and surroundings, and noise regulations change – the England permitted-development limit changed to 37dB(A) under MCS 020(a) on 28 May 2026, and rules differ in Wales, Scotland and Northern Ireland. The figures here are typical estimates, not guarantees. Always get a professional survey and MCS 020 noise assessment for your specific property, and confirm current planning rules, before proceeding.
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