Most modern air source heat pumps aren’t loud. In normal use, an ASHP typically produces a gentle hum of around 40 decibels—roughly the same as a fridge or dishwasher. The real secret to a quiet system isn’t the model alone; it’s smart siting, careful installation, and good design.
Worried your new heat pump will drone away like a helicopter idling in the garden? You’re not alone. It’s one of the most common questions we hear from homeowners across Manchester and Greater Manchester—right up there with “will it work in winter?” and “how much will I save?”
The short version: no, a well-installed air source heat pump shouldn’t turn your back garden into a runway. But noise concerns are worth taking seriously, because where you put the unit and how it’s fitted make a genuine difference. Get those bits right, and most people barely notice it’s there.
In this guide, we’ll explain what a heat pump actually sounds like, what makes some noisier than others, and where to put yours to keep things peaceful. We’ll also cover the UK rules you need to know and share the siting mistakes we see far too often.
Are heat pumps loud in real life?
Let’s start with what you’ll actually hear. An air source heat pump (ASHP) makes noise from two main components: the fan, which draws air across the unit, and the compressor, which pressurises the refrigerant to raise its temperature. Together, they produce a low, steady hum.
How loud is that? According to reporting from The Guardian (2024), a typical ASHP runs at around 40 decibels—comparable to a fridge or a quiet conversation. On particularly cold days, when the unit has to work harder, it can climb towards 60 decibels. That’s still roughly the level of a gas boiler firing up, so we’re not talking about anything dramatic.
Here’s the thing about perception, though. You’ll notice a 40-decibel hum far more in a silent garden at 11pm than you ever would during the morning school run. Context matters. The sound itself is modest; it’s whether it stands out against everything else that people tend to react to.
Reassuringly, a UK Government survey found that only 4% of people living near a heat pump noticed its sound from indoors. For comparison, 57% noticed barking dogs. So if you’re picturing constant complaints from over the fence, the evidence suggests otherwise.
Are heat pumps noisy, or is it something else?
When a heat pump genuinely bothers someone, it’s usually not the machine—it’s how it was installed. There’s a big difference between normal operating sound and a problem that needs fixing.
Normal sounds include:
- A steady, low hum from the fan and compressor
- A slightly louder period during the defrost cycle, when the unit clears ice in cold weather
- A gentle whoosh of moving air
Problem sounds, on the other hand, are your clue that something’s off:
- Rattling or buzzing usually points to loose panels or poor mounting
- A tonal, persistent hum can mean vibration is resonating through the building
- Whooshing or straining airflow often signals an obstruction restricting the fan
The good news is that nearly all of these issues are preventable. As Jack Harvie-Clark of Apex Acoustics told The Guardian, “Modern heat pumps can be significantly quieter, and proper placement—away from property boundaries—can further reduce noise impact.” That’s exactly why quality installation and proper commissioning matter so much.
What affects ASHP noise the most
Some factors are baked into the unit; others come down to the person fitting it. Here’s what really moves the needle.
Unit choice and sound ratings
Manufacturers publish sound figures for their units, but there’s a catch worth understanding. Sound power is the total noise a unit generates at the source, while sound pressure is what you’d actually hear at a set distance. Spec sheets usually quote both, and they can look very different. A higher sound power figure doesn’t automatically mean a noisy garden—distance and siting change everything. Some manufacturers also make low-noise models that trade a sliver of efficiency for a quieter run.
Installation quality
This is the unglamorous bit that makes the biggest difference. A heat pump sitting on a level, solid base with proper clearances and anti-vibration mounts will be far quieter than the same unit bolted carelessly to a wall. Good pipework support, sturdy brackets, and keeping the unit from touching the fabric of the house all stop vibration transmitting indoors. Cut corners here and even a premium unit can hum through your living room wall.
Siting and reflections
Sound bounces. Tuck a unit into a tight corner and hard surfaces will reflect the noise back and forth, amplifying it. Narrow side passages act like a tunnel, funnelling sound towards windows. Where the unit sits relative to walls, fences, and openings genuinely changes how loud it feels.
Operating conditions
During a cold snap, the defrost cycle kicks in more often, and the unit works harder. You might notice it a touch more on a frosty January morning. It’s temporary, though—not a constant drone. It’s also worth knowing that running a heat pump like a gas boiler, flicking it on and off, forces it to work harder and louder. A steady, continuous flow keeps things both quieter and more efficient.
Best heat pump location to reduce noise
If you take one thing from this heat pump siting guide, make it this: placement is everything. Here’s a homeowner-friendly checklist we use when planning a quieter installation.
- Keep it away from bedroom windows where you can—yours and your neighbours’.
- Avoid narrow side passages that tunnel and amplify sound.
- Don’t box it in. A heat pump needs generous airflow, so cramming it into a tight enclosure can actually increase noise through turbulence.
- Mind the boundary. Position it thoughtfully relative to neighbouring properties and, where possible, on the “quiet side” of the house.
- Choose solid ground over resonant timber decking. If decking is unavoidable, it needs reinforcing to stop it acting like a drum.
- Leave room for servicing. A clever position that no engineer can reach is a false economy.
Every property is different. A detached home has options a mid-terrace simply doesn’t, and a compact garden needs more careful thought. If space is tight, that’s exactly where a proper survey earns its keep.
ASHP noise UK rules and neighbour considerations
Most domestic heat pumps can be installed under permitted development, which means you won’t usually need full planning permission. That said, the rules do come with conditions around siting and noise, so it’s worth understanding the basics.
In England, the rules were updated on 29 May 2025. According to MCS Certified, the changes now allow a heat pump to be installed within one metre of a property boundary, increase the permitted size, and let detached homes install up to two units. Installations in England must comply with the updated MCS 020 a) planning standard, while Scotland, Wales, and Northern Ireland continue to follow MCS 020.
In practice, a competent installer designs around these requirements from the start, running a sound calculation to check the unit meets the noise limits at your neighbour’s windows and doors. If your property is tight on space or you share close boundaries, a professional assessment is the safest way to avoid any nasty surprises down the line.
Common noise mistakes we see
Over the years, we’ve been called out to plenty of installations that other people got wrong. The usual suspects:
- Mounting the unit directly to a resonant wall with no vibration isolation
- Squeezing it into a corner where sound reflects and builds
- Fitting it under a bedroom window purely because “it fit”
- Obstructing airflow, which adds turbulence and perceived noise
- Poorly clipped pipework that carries vibration straight indoors
Almost every one of these is avoidable with a bit of planning. That’s really the whole point of a design-led approach.
Quick wins to make an existing heat pump quieter
Already have a unit that’s noisier than you’d like? A few things are worth checking:
- Clear leaves and debris and keep airflow paths open
- Book a service—a well-maintained unit runs more smoothly
- Have an installer refit or upgrade the anti-vibration mounts
- Tighten any loose panels or brackets
- Consider properly specified acoustic solutions—but please, no DIY soundproof boxes, which starve the unit of air and cause more problems than they solve
What to expect when we plan a quieter installation
We’re a small number of Heat Geek certified installers in Greater Manchester, and we’re also MCS accredited and members of the APHC, RECC, and IWA. What that means for you is simple: we don’t just swap a boiler for a heat pump and hope for the best.
Every job starts with a full heat loss survey and a system designed from scratch around your home—no templates, no guesswork. We’ll talk through siting with you, weighing up bedroom windows, neighbour boundaries, and service access before anything gets fitted. Then we install neatly, commission the system properly, and stay on hand afterwards to answer questions.
With 143 five-star Trustpilot reviews and up to £7,500 available through the Boiler Upgrade Scheme for eligible homes, switching from gas is more affordable than many people expect. And if your garden’s small and you’re worried about noise, that’s precisely the sort of thing we love figuring out.
Frequently asked questions
Are heat pumps loud compared to a gas boiler?
Not really. A typical ASHP runs at around 40 decibels, which is comparable to a gas boiler firing up. On very cold days it can rise towards 60 decibels, but that’s temporary and still fairly modest.
Are heat pumps noisy at night?
The sound level doesn’t change much at night, but you’re more likely to notice a low hum when everything else is quiet. Good siting away from bedroom windows and steady operation both help keep night-time noise unobtrusive.
What does an ASHP sound like in winter or during defrost?
During cold weather, the defrost cycle runs more often and the unit works a little harder, so you may hear it slightly more. It’s a brief, occasional change rather than a constant increase in volume.
Where’s the best heat pump location to reduce noise in a small garden?
Aim for a spot with good airflow, away from bedroom windows and tight corners, on solid ground, and thoughtfully positioned relative to your neighbours. In a compact garden, a professional survey is the best way to find the ideal location.
Can I put a heat pump next to a fence or wall?
You can, but hard surfaces reflect sound and can make it seem louder, especially in a corner. Leaving adequate clearance for airflow and avoiding “sound traps” makes a real difference.
Do anti-vibration mounts actually work?
Yes. They stop vibration transmitting from the unit into the building or its base, which is one of the most common causes of an intrusive hum indoors. They’re a small detail with a big impact.
Will my neighbours hear my heat pump?
Usually not to any bothersome degree. A UK Government survey found just 4% of people living near a heat pump noticed it from indoors. Correct siting and a compliant sound calculation keep neighbour impact to a minimum.
Do I need planning permission for a heat pump in the UK?
Most domestic installations fall under permitted development, so full planning permission usually isn’t needed—provided the installation meets the relevant conditions. In England these follow the MCS 020 a) standard as of May 2025. If your property is unusual or space is tight, it’s worth getting a professional assessment.
Can an installer move an existing unit to make it quieter?
Yes. If a unit was poorly sited, relocating it, improving its mounting, or clearing airflow obstructions can significantly reduce noise. An installer can assess what’s causing the problem and recommend the right fix.
Does servicing reduce heat pump noise?
It can. Regular servicing keeps fans, panels, and components in good order, which helps the system run smoothly and quietly. A neglected unit is far more likely to rattle or strain.
Ready to keep things quiet?
Modern air source heat pumps aren’t the noisy beasts some people fear. In most homes, correct siting and quality installation mean you’ll barely notice yours is there. The trick is getting the design right from the outset—and that’s where we come in.
If you’re in Manchester or Greater Manchester and thinking about making the switch, we’d love to help. Get in touch for a free, no-obligation survey and quote, and we’ll talk through the best location for your home, guide you through the Boiler Upgrade Scheme, and design a system that’s as quiet as it is efficient. Give us a shout—especially if that small garden’s got you worried. We’ll sort it.