Can You Get a Heat Pump in a Terraced House?

Estimate the Saving for Your Terraced House

Can You Install a Heat Pump in a Terraced House?

The short answer is yes: heat pumps work well in terraced houses, and thousands have already been installed across the UK. However, terraced properties do present some specific challenges around space, noise, and planning that are worth understanding before you commit. This guide covers everything you need to know.

Space for the Outdoor Unit

An air source heat pump requires an outdoor unit (a box roughly the size of a large suitcase) that extracts heat from the outside air. This unit needs to be sited carefully to work effectively and comply with planning and noise rules.

The main space requirements are:

• Clearance behind and to the sides. Don't take a number from a guide, including this one: every manufacturer publishes its own minimum clearances in the installation manual and they differ a lot between models. Ask your installer to show you the clearance diagram for the exact unit they're quoting, on your exact wall. It's a common reason a unit that "fits" on paper doesn't.
• The unit must not be positioned in an enclosed space or tight alleyway where discharged cold air will recirculate back in. This one matters more than raw clearance: a heat pump re-breathing its own cold exhaust loses efficiency all winter.
• It should be accessible for annual servicing
• There is no longer any minimum distance to the property boundary in England or Wales, so a narrow yard is not the blocker it was before May 2025

Most typical outdoor units measure roughly 1 metre wide, 0.9 metres tall, and 0.4 metres deep. In a terraced house, the most common locations are:

• Rear garden: usually the easiest option, with the unit against the rear wall or on a side wall
• Front garden: viable if there is sufficient space and the street appearance is acceptable; some local councils restrict this
• Side passage: works if the passage is wide enough (typically needs 2 metres or more width) and is open at both ends

Mid-Terrace vs End-of-Terrace

The position of your terrace property significantly affects both heat loss and installation complexity.

Mid-Terrace Properties

A mid-terrace house shares two walls with neighbours. Those shared walls lose very little heat compared to exposed external walls, which is a genuine advantage: your overall heat demand is lower, meaning you can often get away with a smaller, quieter, and cheaper heat pump unit. A typical well-insulated mid-terrace might only need a 5kW to 7kW unit.

The challenge for mid-terrace is outdoor space. With only front and rear access, there is less flexibility in where to position the unit. If your rear garden is very small or you have a shared rear access, fitting the unit without infringing on neighbours' space requires careful planning. An installer experienced with terraced houses will know how to work within tight sites.

End-of-Terrace Properties

End-of-terrace houses have one more exposed external wall than a mid-terrace, which increases heat loss, particularly in older, poorly insulated properties. You may need a slightly larger heat pump as a result, typically 7kW to 10kW depending on insulation levels and house size.

The upside is more outdoor space. An end-terrace often has a side wall that is an ideal location for the outdoor unit, with good airflow and less visual impact on the garden.

Noise Considerations

Noise is the concern terraced house owners raise first, and it's also where the numbers get muddled, so here's the one thing to get straight before you compare anything.

Manufacturers publish two different decibel figures and they are not interchangeable. Sound power level (Lw) is a property of the machine, measured in a lab, independent of where you stand. Sound pressure level (Lp) is what you'd actually hear at a stated distance, and it falls away as you move back. A unit with a sound power level of 54 dB(A) produces roughly 46 dB(A) at one metre and roughly 37 dB(A) at three metres in the open. Same machine, three very different-looking numbers, and all three get printed as "dB(A)" with no qualifier. That's how one heat pump can honestly be advertised at 54 and at 46.

The figure to compare on is sound power level, because that's what the MCS 020 a) calculation is built from, and MCS now holds A-weighted sound power levels for certified products on its Product Directory so installers use the right one. Mainstream domestic units land in the 45 to 56 dB(A) band, and our heat pump noise guide lists what each manufacturer publishes alongside the basis they publish it on. Vaillant currently markets the newest aroTHERM plus at "44 dB(A)" without stating a basis anywhere on the product page, and its 7kW Arotherm Plus is widely quoted at 54 dB(A). Those two numbers cannot both be sound power for comparable units, which tells you everything about why you should ask "on what basis?" before you compare any two heat pumps on noise.

The planning rule in England and Wales is MCS 020 a): the calculated sound pressure must be 37.0 dB(A) or lower at the assessment position, which MCS defines as 1 metre outside the centre of any door or window to a habitable room of a neighbouring property. Your installer calculates it from the unit's sound power level, the directivity, the distance and any solid barrier in between. The widely quoted 42 dB(A) is the older MCS 020 figure, which still applies in Scotland and Northern Ireland but has not applied in England since 29 May 2025 or in Wales since 1 June 2026. A barrier only counts if it breaks the line of sight: MCS 020 a) gives a heavy solid barrier 10 dB when the unit is completely hidden, 5 dB for a partial view, and nothing at all if the unit is still in full view.

Ask your installer for the completed MCS 020 a) calculation for your specific site, not a reassurance. In a terrace the distances are short enough that the answer genuinely depends on which wall you pick.

Planning Permission

Most terraced house heat pump installations qualify as permitted development, meaning you don't need to apply for planning permission. The rules changed substantially in England on 29 May 2025, and if you're reading an older guide you'll still see the version that was scrapped.

England, from 29 May 2025 (SI 2025/560)

• The one-metre-from-the-boundary rule is gone. Paragraph G.2(e) of the permitted development order was deleted outright, so there is now no minimum boundary distance at all. For a mid-terrace with a narrow back yard this is the single biggest change, because the old rule ruled out a lot of terraces.
• The size limit went up from 0.6m³ to 1.5m³ for a house. A block of flats is still capped at 0.6m³.
• Detached houses can have two heat pumps. Terraces, semis and blocks of flats are limited to one.
• The unit must not be used solely for cooling, which is what lets cooling-capable and air-to-air units through.
• The installation must comply with MCS 020 a), whether or not it's an MCS-certified installation.

What still isn't permitted development in England

• Anything at a listed building, or on land in its curtilage. Listed properties need consent, full stop.
• Anything on a scheduled monument, or on a pitched roof, or within 1 metre of the edge of a flat roof.
• In a conservation area or World Heritage Site: a unit on a wall or roof fronting a highway, or sited nearer to a bounding highway than the house itself. Everywhere else in a conservation area is still permitted development, which is a more useful answer than "conservation areas need planning permission".
• Everywhere else: a wall-mounted unit on a highway-facing wall above ground floor storey level.
• A heat pump where a wind turbine is already installed at the property.

Elsewhere in the UK

• Wales: caught up on 1 June 2026 (WSI 2026/79). Its three-metre boundary rule was deleted, the size limit went to 1.5m³ for a house (1m³ for a block of flats), detached houses can have two units, the unit must not be solely for cooling, and Wales adopted MCS 020 a). The conservation area and highway restrictions mirror England's.
• Scotland and Northern Ireland: still working to the older MCS 020 standard and their own permitted development rules. Check with your local planning authority rather than assuming the English rules apply.

You can usually get a definitive answer with a simple pre-application enquiry, which is free in most councils.

Typical Costs for a Terraced House

Those figures sit inside the £9,000 to £13,000 band we use across the site, with a mid-terrace at the small end because two shared walls cut the heat demand. The Energy Saving Trust puts the typical air source install at around £12,000, which is roughly where an end-terrace needing a few radiators lands. The Boiler Upgrade Scheme (BUS) grant of £7,500 applies equally to terraced houses as to any other property type, provided you meet the eligibility criteria. That brings the net cost down to around what a new gas boiler costs (about £2,750 fitted). See our heat pump grants guide for full eligibility details.

Is a Heat Pump Right for Your Terraced House?

A heat pump is likely to be a good fit for your terraced house if:

• You have loft insulation and at least cavity wall insulation
• You have a garden or side passage for the outdoor unit
• You are not in a conservation area with restrictions on external works
• Your current energy bills are high and you want to reduce running costs over time

If your home has solid walls and poor insulation, tackling insulation first will make the heat pump more efficient and may allow a smaller, quieter unit. See our guide on insulating your home before a heat pump for the recommended order of works.