With the rise in energy-conscious living and the push to reduce carbon emissions, heat pumps have become a popular choice for homeowners across Edinburgh and beyond. Whether you’re considering an air source heat pump or a ground source heat pump, choosing the right location is essential for your heat pump system to run efficiently and meet building regulations.
In this blog, we’ll guide you through the heat pump location rules: what you need to know before heat pump installation in Scotland
Why Heat Pump Location Matters
The heat pump unit is responsible for drawing in air or ground energy to deliver space heating and hot water to your home. To do this effectively, it needs the best location possible — both indoors and outdoors.
Where your pump unit is placed affects everything from energy efficiency, noise levels, and air flow, to compliance with planning permission and building regulations. Getting the location wrong could mean your system doesn’t work efficiently, causes noise pollution, or fails to qualify under permitted development rights.
Heat pumps come in different shapes and sizes, so read our guide, ‘How much space do you need for a heat pump?‘, for more information.
Where should the outdoor unit go?
An air source heat pump’s outdoor unit sits either at ground level on a base, or on a wall-mounted bracket. Whichever route you take, the unit needs to breathe. It works by pulling in outside air, taking heat out of it, and blowing the colder air back out. Starve it of airflow and it recirculates its own exhaust, which drags efficiency down and makes it work harder for the same result.
That rules out a few tempting spots straight away:
- Tucked into a narrow side passage between two walls
- Boxed in behind fence panels or dense planting
- Under a low overhang with nowhere for the discharged air to go
- Anywhere the discharge blows straight at a wall a short distance away
Follow the manufacturer’s clearance figures rather than a rule of thumb — they vary between models, and they’re different for the intake face, the discharge face and the service side.
The base matters too. Ground-level units want a properly laid concrete pad or purpose-made feet on solid ground, not slabs sitting on soil that’ll settle over a winter. Wall brackets need masonry that can genuinely carry the load, which on a Scottish stone or rubble-filled wall is a judgement call for the installer, not an assumption.
What about noise-sensitive positions?
Keep the unit away from bedroom windows — yours and your neighbours’ — and think about where the sound will land rather than only where the unit sits. Hard surfaces reflect. A unit in a corner formed by two walls is measurably louder at the neighbour’s window than the same unit in open air.
Can I put the outdoor unit on a flat roof?
Sometimes, but treat it as the exception rather than a convenient default.
Roof installations bring three problems at once: structural loading, vibration transmitted into the building, and planning. Keep the unit well back from the roof edge — too close and you disrupt airflow and change how the sound carries. Anti-vibration mounts are not optional up there; a unit hard-fixed to a roof deck can turn the whole structure into a sounding board.
On planning, roof-mounted units are one of the most common ways an installation falls outside permitted development. Pitched roof installs in particular are a recognised pitfall. Confirm the route before you commit to the position.
Where does the indoor unit and hot water cylinder go?
The indoor equipment — the hydronic unit and, in almost all cases, a hot water cylinder — needs somewhere practical and accessible.
Two things people underestimate:
Cylinders for heat pumps are bigger than the ones they replace. A heat pump stores hot water at a lower temperature than a gas boiler heats it to, so the cylinder has to hold more of it to give you the same usable hot water. If you’re replacing a combi, you’re finding space for a cylinder that wasn’t there before. That’s often the single biggest practical constraint in a flat or a small terrace, and it’s better discovered at survey than on install day.
“Fits” and “serviceable” are different things. The unit has to physically go in, and an engineer has to be able to work on it for the next fifteen years. Leave real clearance in front of it.
Do I need planning permission for a heat pump?
In most cases, no. Domestic heat pumps generally fall under permitted development, which means they’re allowed automatically provided they meet a set of conditions.
The important thing in 2026: the rules are different in each UK nation, and England changed while the others didn’t. A lot of online guidance is written for England and quietly wrong everywhere else.
What changed in England?
On 29 May 2025 England removed the old requirement to site the unit at least 1 metre from the property boundary, and it now allows a unit up to 1.5 cubic metres on a house, against 0.6 cubic metres previously. Detached houses can have two units under permitted development; other houses and blocks of flats are limited to one. Air-to-air systems that also cool were brought into scope.
For a terraced house with a narrow garden, that single change removed the biggest obstacle there was.
What are the rules in Scotland, Wales and Northern Ireland?
This is where English headlines cause trouble.
| Nation | Boundary distance | Notes |
|---|---|---|
| England | No minimum since 29 May 2025 | Up to 1.5m³ on a house; two units on a detached home |
| Scotland | 1 metre still applies | Separate order; has not followed England’s 2025 relaxation |
| Wales | 3 metres | Rules out permitted development for most terraces and semis |
| Northern Ireland | 1 metre still applies | Broadly similar to England’s pre-2025 regime |
If you’re in Scotland, the scrapped boundary rule and the two-unit allowance you’ll read about on English sites don’t apply to you. Same for the larger unit size. Worth saying plainly, because it’s the most common piece of misinformation reaching Scottish homeowners right now.
When do I definitely need permission?
- Listed buildings. Permitted development doesn’t apply. You’ll need Listed Building Consent, and usually planning permission alongside it. Heat pumps do go onto listed homes — the route is a full application, and a discreet, reversible installation is much more likely to be approved.
- Scheduled monuments. Permitted development rights don’t apply within the curtilage.
- Conservation areas and World Heritage Sites. Permitted development can still apply, but the siting is restricted. In England the unit must not go on a wall or roof fronting a highway, or nearer to a bounding highway than the building itself. In Scotland the practical position is tighter again — rear elevation, ground level.
- Article 4 directions. Councils can strip permitted development rights from specific streets. Rare for heat pumps, but check your address on the council’s planning portal.
- Flats and tenements. More restrictive, and shared ownership of the building complicates it further. In a tenement there are usually limits on how many units the building can have at all, plus the question of who actually owns the wall you’re fixing to.
Permitted development doesn’t require you to notify your neighbours. There’s no statutory consultation step. But if the unit is going close to a boundary, a conversation with the neighbour whose window is nearest is worth ten minutes of your time — it’s far cheaper than a noise complaint after the fact.
How loud is a heat pump, and how is the noise assessed?
Modern units are quiet in absolute terms. The issue is rarely the unit — it’s where it ends up.
Permitted development depends on passing an MCS 020(a) sound calculation, carried out by your installer for the specific proposed position. It isn’t a measurement taken afterwards; it’s a calculation done in advance, and it’s the reason position and planning status are the same conversation.
Two things worth knowing:
- The threshold figure is in flux. MCS 020 has historically set the limit at 42 dB(A) at the assessment position of the nearest noise-sensitive premises, and that’s the figure quoted for Scotland. Some current guidance for England cites 37 dB(A) under the updated MCS 020(a). Ask your installer which figure applies to your job and which version they’re calculating against.
- From 28 May 2026, MCS 020(a) becomes the only accepted certification scheme for this purpose. Older noise standards no longer count.
Make sure the calculation is completed for your actual proposed position and kept on file. If a neighbour ever raises a complaint, that document is your defence. Ask for a copy.
Practically, sound performance improves when the unit is in open air rather than a corner, on anti-vibration mounts, on a solid base, and pointed away from habitable windows. It gets worse when the unit is squeezed between reflective surfaces, hard-fixed to a lightweight structure, or boxed in by a well-meaning acoustic enclosure that also blocks the airflow.
What’s different about ground source heat pumps?
Ground source systems take heat from the ground rather than the air, using either horizontal loops in trenches or vertical boreholes. They run more efficiently than air source and there’s no outdoor unit to site or listen to.
The trade-off is land and groundworks. Horizontal loops need a genuinely large area — this is not a small-garden option. Boreholes need much less surface area but cost considerably more and bring drilling access to your property.
Ground conditions decide feasibility, and that’s an assessment, not a guess. Your installer should be establishing what’s under the garden, whether there’s access for the plant, and whether any environmental notification or licensing applies — open-loop and borehole systems in particular can bring the environmental regulator into the picture. In Scotland that’s SEPA; in England, the Environment Agency.
Ground and water source systems are usually permitted development too, with the same listed building and conservation area exclusions as air source.
What should a proper siting survey cover?
This is the bit that separates a considered installation from a unit bolted wherever the pipework was easiest.
- Heat loss calculation for the property, before any equipment is chosen. Sizing comes from the building, not from the old boiler’s output.
- The actual proposed position, marked up, with manufacturer clearances checked against it.
- The MCS 020(a) sound calculation for that specific position, with a copy for you.
- Planning status confirmed for your nation and your property — including listed status, conservation area, and any Article 4 direction.
- Where the cylinder is going, and whether it genuinely fits with servicing space.
- Condensate drainage from the outdoor unit. Air source units produce condensate and shed defrost water. In a Scottish winter that water will freeze on whatever it lands on. A unit sited above a path or a doorstep without proper drainage creates an ice hazard every cold morning — and it’s entirely avoidable at design stage.
- The base and fixings, specified rather than assumed.
If a quote arrives without a position identified and a sound calculation attached, it isn’t a finished design. It’s a price.
Getting It Right With The Edinburgh Boiler Company
At The Edinburgh Boiler Company, we understand the importance of finding the best location for your heat pump installation. Whether you’re replacing a gas boiler or upgrading your heating system for better energy efficiency, our suitably qualified heating engineers are here to ensure your indoor and outdoor unit setup is safe, compliant, and optimised for performance.
We assess every site for air flow, noise impact, structural integrity, and proximity to neighbouring properties. We also guide you through development rights, planning permission, and help you make a smooth transition to a cleaner, more sustainable future.
