Heat Pump Installation UK: The Complete Guide

Installing a heat pump is one of the biggest home improvements you can make — and one of the smartest. A well-installed heat pump will heat your home and hot water for 20 to 25 years, cut your carbon emissions dramatically, and in many cases reduce your energy bills. But the installation process can feel opaque if you have never been through it before.

This guide walks you through every stage of a heat pump installation in the UK, from your first enquiry right through to handover and beyond. Whether you are considering an air source heat pump or a ground source system, the fundamental process follows the same path — and understanding it will help you make better decisions, avoid common pitfalls, and get a system that performs brilliantly for decades.

Stage 1: The Initial Enquiry and Heat Loss Survey

Every proper heat pump installation starts with a detailed heat loss survey. This is not a quick glance at your home — it is a room-by-room assessment that determines exactly how much heat your home loses and therefore how much heat the pump needs to deliver.

What happens during a heat loss survey?

An MCS-certified surveyor will visit your home and measure every room. They record wall construction, insulation levels, window types, floor areas, ceiling heights, and the orientation of each wall. They note draughts, check loft insulation depth, and assess your existing radiators or underfloor heating.

This data feeds into MCS-approved design software that calculates the peak heat demand for each room and for your home as a whole. The result — measured in kilowatts (kW) — determines what size heat pump you need.

Why the survey matters so much

An undersized heat pump will not keep your home warm on the coldest days. An oversized one will cost more to buy and may cycle on and off inefficiently, increasing wear and reducing lifespan. The heat loss survey is the foundation of the entire installation — skip it or rush it and everything else suffers.

A thorough survey takes 90 minutes to three hours. If a company offers to quote without visiting your home, that is a significant red flag. Use our suitability checker to get an initial sense of whether a heat pump suits your property, but always insist on a proper on-site survey before committing.

Stage 2: System Design and Quotation

After the survey, the installer designs your system. This includes selecting the right heat pump model, determining whether your existing radiators are adequate (or whether some need upgrading), specifying the hot water cylinder, planning the pipework routes, and identifying where the outdoor unit will sit.

What a good quote includes

A proper quote should itemise everything:

Heat pump unit: Make, model, and output capacity
Hot water cylinder: Size and specification (typically 150 to 250 litres)
Radiator upgrades: Which radiators need replacing and why
Pipework: Route from outdoor unit to indoor system
Electrical work: Any consumer unit upgrades needed
Controls: Thermostat, zone valves, weather compensation
BUS grant deduction: The £7,500 grant should be shown as a deduction
Total cost after grant: What you actually pay

Always get at least three quotes from different MCS-certified installers. This gives you a range of prices and approaches to compare. Typical costs after the BUS grant range from £2,500 to £7,000 for most homes — check our full cost guide for detailed breakdowns.

Stage 3: Grant Application and Planning

Once you have chosen your installer, two things happen in parallel: the grant application and any necessary planning or preparation work.

BUS grant application

Your installer submits the Boiler Upgrade Scheme application to Ofgem on your behalf. You need to provide consent and some basic property information, but the installer handles the paperwork. Approval typically takes two to four weeks. The voucher is valid for three months, giving a reasonable window for the installation to take place.

Planning permission

Most air source heat pump installations fall under permitted development rights, meaning no planning permission is needed provided the system meets certain conditions — including noise limits and positioning at least one metre from the property boundary.

Ground source heat pumps typically do not need planning permission either, though horizontal ground loops require sufficient garden space and vertical boreholes may need a permit from the Environment Agency.

Listed buildings, properties in conservation areas, and flats always need to check with the local planning authority first.

Stage 4: Pre-Installation Preparation

Before the installers arrive, there are a few things to sort out:

What the installer prepares

Equipment ordering: Heat pump, cylinder, radiators, pipework, fittings, controls — everything arrives on site on day one
Scaffolding (if needed): Occasionally required for high-level pipework or difficult access
Electrical assessment: Confirming your consumer unit can handle the heat pump's electrical demand

What you need to do

Clear the area where the outdoor unit will be installed — typically a concrete pad or pre-cast base alongside the house
Clear space for the hot water cylinder if one is being installed (usually an airing cupboard or utility room)
Move furniture away from radiators that are being replaced
Make sure there is clear access for the installers to move between rooms and carry equipment
Accept that there will be some disruption — dust, noise, and temporary loss of heating and hot water

Stage 5: Installation Day by Day

A typical air source heat pump installation takes two to four days. Here is what happens on each day, based on a standard three-bedroom semi:

Day 1: Out with the old

The existing boiler is drained and disconnected. If you have a traditional system with header tanks in the loft, those come out too. The old system is drained down and the boiler is removed. The installers may also start preparing the base for the outdoor heat pump unit and begin routing new pipework.

You will have no heating or hot water from this point until the new system is commissioned. If the installation is in winter, plan accordingly — electric heaters, extra blankets, and patience.

Day 2: The new system goes in

The outdoor heat pump unit is positioned on its base and secured. The hot water cylinder is installed indoors. Pipework is run from the outdoor unit through the external wall to the indoor system, fully insulated to prevent heat loss and condensation. Any new or upgraded radiators are fitted.

Day 3: Connections and controls

The electrical connection is made — either by the installation team's qualified electrician or a separate electrical contractor. The system is filled, pressurised, and leak-tested. Controls are wired in, including the room thermostat, weather compensation sensor, and any zone controls. The system is powered on for initial testing.

Day 4 (if needed): Commissioning and handover

The system is formally commissioned according to MCS standards. The installer checks flow temperatures, heat output, hot water performance, and system pressures. They programme the controls, set the heating schedules, and adjust the weather compensation curve to suit your home. Then they walk you through how everything works.

Stage 6: Commissioning

Commissioning is the formal process of verifying that the heat pump system is working correctly and efficiently. It is an MCS requirement and should not be skipped or rushed.

What commissioning involves

Flow temperature checks: Verifying the system delivers heat at the designed flow temperatures (typically 35 to 45 degrees Celsius for a well-insulated home)
Heat output measurement: Confirming each radiator delivers the expected heat output
Hot water performance: Testing that the cylinder reaches the required temperature (typically 48 to 55 degrees Celsius, with periodic legionella pasteurisation cycles to 60 degrees)
System pressure: Checking and recording the operating pressure
Electrical safety: Verifying all electrical connections are safe and comply with Part P regulations
Noise levels: Confirming the system operates within planning and MCS noise limits
Weather compensation setup: Programming the heating curve so the system adjusts output based on outdoor temperature

Stage 7: Handover

The handover is when the installer formally passes the system to you. A good handover includes:

Documentation you should receive

MCS installation certificate
Manufacturer's warranty documents (typically 5 to 10 years)
Building regulations compliance certificate (or notification through the Competent Persons Scheme)
Commissioning record
System design documentation showing heat loss calculations
User guide for the controls
Emergency contact details for the installer

What you should understand before the installer leaves

How to adjust the heating temperature and schedule
How the hot water works and when it heats
What the normal operating pressures are
What the weather compensation setting does and why you should leave it alone
When to book the first annual service
What counts as normal behaviour (defrost cycles, fan noise at different speeds)

Air Source vs Ground Source: Installation Differences

The stages above apply to both types, but there are key differences:

Air source heat pump installation

Outdoor unit placed on a concrete base or anti-vibration mounts
Pipework through the external wall (one penetration point)
Installation typically takes 2 to 4 days
Minimal garden disruption
Lower cost: typically £10,000 to £14,000 before the grant

Ground source heat pump installation

Requires ground works: either horizontal trenches (1 to 1.5 metres deep across a large area of garden) or vertical boreholes (75 to 200 metres deep)
Ground works typically take 1 to 3 days on top of the indoor installation
Total installation: 1 to 2 weeks
Higher upfront cost but greater efficiency, especially in cold weather
Garden will need time to recover from trenching

How Much Does Heat Pump Installation Cost?

For a typical three-bedroom semi-detached home:

Air source heat pump: £10,000 to £14,000 total, or £2,500 to £6,500 after the £7,500 BUS grant
Ground source heat pump: £18,000 to £35,000 total, or £10,500 to £27,500 after the grant

Costs vary depending on your home's size, insulation level, how many radiators need upgrading, and regional labour rates. Use our heat pump calculator for a personalised estimate, or get free quotes from local MCS-certified installers.

Common Installation Mistakes to Avoid

Understanding these common pitfalls will help you get a better installation:

Skipping the heat loss survey: No proper survey means no proper system design. Insist on a room-by-room assessment
Oversizing the heat pump: Bigger is not better. An oversized pump cycles on and off, reducing efficiency and increasing wear
Not upgrading radiators where needed: Heat pumps run at lower temperatures than boilers. Some radiators may need to be larger to deliver enough heat
Poor pipework insulation: Uninsulated or poorly insulated pipework between the outdoor unit and your home wastes energy
Setting flow temperatures too high: Running at 55 degrees like a boiler defeats the purpose. A well-designed system should run at 35 to 45 degrees
Choosing on price alone: The cheapest quote may mean cut corners. Quality of design and installation determines long-term performance

After Installation: The First Few Weeks

A heat pump works differently from a boiler, and it takes a little time to adjust. Here is what to expect:

Lower radiator temperatures: Your radiators will feel warm rather than hot. This is normal — the system is designed to provide gentle, consistent heat rather than short blasts of high-temperature heat
Longer run times: Heat pumps run for longer periods at lower intensity. Leaving the system on for extended periods (or continuously) is more efficient than short on-off cycles
Defrost cycles: In cold weather, the outdoor unit will periodically reverse to defrost the evaporator. You may see steam and hear the fan change speed. This is completely normal
Weather compensation adjustments: Your installer may need to tweak the heating curve over the first few weeks. Some installers offer a follow-up visit after a month to fine-tune settings

The key thing is to resist the urge to crank up the temperature. Let the system run as designed, and if something does not feel right after a couple of weeks, contact your installer to adjust the settings rather than overriding them.

Frequently Asked Questions

How long does a heat pump installation take?

A typical air source heat pump installation takes 2 to 4 days. Ground source installations take 1 to 2 weeks including the ground works.

Do I need planning permission for a heat pump?

Most domestic air source heat pump installations fall under permitted development rights and do not need planning permission. Check with your local authority if you live in a listed building, conservation area, or flat.

Can I install a heat pump myself?

You could technically buy and install a heat pump, but you would not be eligible for the £7,500 BUS grant (which requires an MCS-certified installer) and the work must comply with building regulations. Self-installation is not recommended.

Will I need a new hot water cylinder?

If you currently have a combi boiler (no cylinder), yes — you will need a hot water cylinder installed. If you already have a cylinder, it may need upgrading to one with a larger coil suited to heat pump temperatures.

What happens to my old boiler?

Your installer removes and disposes of the old boiler as part of the installation. This is normally included in the quoted price.

How disruptive is installation?

Expect 2 to 4 days of disruption including some noise, dust from drilling, and temporary loss of heating and hot water. Most homeowners find it comparable to having a new bathroom fitted — noticeable but manageable.

Do I need to upgrade my electrical supply?

Most homes have sufficient electrical capacity for a heat pump. Your installer will check during the survey. Occasionally a consumer unit upgrade is needed, which adds £200 to £400 to the cost.

What maintenance does a heat pump need?

An annual service by a qualified engineer, similar to a boiler service. You should also keep the outdoor unit clear of leaves and debris, and check the system pressure periodically.

Ready to start your heat pump installation? Get free quotes from MCS-certified installers in your area, use the calculator to estimate your costs, or check the suitability checker to confirm a heat pump is right for your home. You can also read our installation checklist for a printable step-by-step guide.