How Long Does Heat Pump Installation Take? Full UK Timeline

What to Expect: The Full Installation Timeline

Installing a heat pump is a bigger job than swapping a gas boiler, but it is not the major building project some homeowners fear. Understanding the full timeline, from first enquiry to a fully operational system, helps you plan properly and set realistic expectations.

The total process typically takes 4 to 8 weeks from initial survey to commissioning, though the actual hands-on installation work is usually completed in 2 to 4 days. Most of the elapsed time is taken up by surveys, design work, grant applications, and scheduling.

This guide breaks down each stage so you know exactly what happens, how long it takes, and how to keep things moving smoothly.

Stage 1: Initial Survey and Heat Loss Calculation (1 to 2 Weeks)

Before anything else, a qualified engineer needs to visit your property to assess it. This initial survey is a critical step that determines the size and type of heat pump you need.

What Happens During the Survey

A thorough survey typically takes 2 to 3 hours and covers:

Heat loss calculation: The engineer measures your property, notes insulation levels, window types, wall construction, and room dimensions. This data is used to calculate exactly how much heat your home loses, which determines the size of heat pump required.
Existing heating assessment: Your current radiators, pipework, and hot water cylinder are inspected. The engineer will identify whether any radiators need upgrading to work efficiently at lower flow temperatures.
Outdoor unit positioning: The engineer identifies the best location for the external unit, considering noise regulations, airflow requirements, distance from boundaries, and visual impact. See our planning permission guide for the rules around positioning.
Electrical supply check: Heat pumps require a dedicated electrical supply. The engineer will check whether your consumer unit and mains supply can accommodate the additional load, or whether an electrical upgrade is needed.
Hot water requirements: Your household's hot water demand is assessed to specify the correct cylinder size and configuration.

The Design and Quotation

After the survey, the installer produces a detailed system design and quotation. This typically takes 3 to 7 working days and should include:

Specified heat pump make and model
Any required radiator upgrades or additions
Hot water cylinder specification
Pipework and electrical requirements
Noise assessment for planning compliance
Total cost breakdown, including any ancillary works
Projected running costs and SCOP

You can use our heat pump calculator to get an initial estimate before the survey, and compare it against the installer's formal quotation.

It is worth getting 2 to 3 quotes from different MCS-certified installers. Our find installer tool helps you connect with qualified engineers in your area. Comparing quotes takes time but ensures you get the right system at a fair price.

Stage 2: Grant Application (2 to 4 Weeks)

If you are applying for the Boiler Upgrade Scheme (BUS) grant, this stage sits between accepting a quote and starting the installation. The grant provides up to £7,500 towards the cost of an air source or ground source heat pump.

How the Grant Process Works

Your installer applies on your behalf through OFGEM's online portal. You do not apply directly.
OFGEM processes the application, which typically takes 2 to 3 weeks, though it can be faster during quieter periods.
Once approved, you receive a voucher with a validity period (usually 3 months) within which the installation must be completed.
The grant is paid directly to the installer, who deducts it from your final bill.

Important: Do not allow any installation work to begin before the grant voucher is issued. Starting work before approval will invalidate your application.

For full details on eligibility and how to apply, see our heat pump grant guide.

If You Are Not Applying for a Grant

Without the grant application step, you can typically move from accepted quote to installation within 1 to 2 weeks, depending on equipment availability and the installer's schedule.

Stage 3: Preparation Before Installation Day (1 to 3 Days Before)

A good installer will help you prepare for the installation. Here is what to expect and what you can do to help things go smoothly.

What Your Installer May Do in Advance

Deliver equipment: The heat pump unit, hot water cylinder, and major components are often delivered a day or two before work begins. Ensure you have somewhere dry and accessible to store them.
Electrical preparation: If an electrical upgrade is needed (new consumer unit, larger supply fuse, dedicated circuit), this may be done as a separate visit before the main installation.
Scaffold or access equipment: If the installation requires working at height (for example, routing pipework through an upper floor), scaffolding may be erected in advance.

What You Should Do

Clear the area around the proposed outdoor unit location. Remove garden furniture, planters, or stored items.
Clear the indoor area where the new hot water cylinder will go. If it is replacing an existing cylinder in an airing cupboard, empty the cupboard.
Ensure clear access from the front of your property to the installation locations. The outdoor unit weighs 60 to 120 kg and needs to be moved on a trolley or carried by two people.
Notify your neighbours. While not legally required, letting neighbours know there will be some noise and activity for a few days is a courtesy that prevents complaints.
Arrange alternative hot water for the installation days. You will likely be without hot water for parts of the process. A kettle and a temporary electric shower (if you have one) can help.

Stage 4: The Installation (2 to 4 Days)

This is the main event. The duration depends on the complexity of your installation, but here is a typical breakdown for a standard air source heat pump installation replacing a gas boiler.

Day 1: Removing the Old System and Preparing

Drain the existing heating system and disconnect the old boiler
Remove the old boiler and, if being replaced, the existing hot water cylinder
Prepare the outdoor unit base. This is usually a concrete plinth or anti-vibration mounting pad on a level surface. If a new concrete base is needed, it ideally should be poured a few days in advance to cure.
Begin pipework runs between the outdoor unit location and the indoor plant room or utility area
Electrical work begins, running a dedicated supply to the outdoor unit location

Disruption level: Moderate. There will be drilling through external walls for pipe runs, which creates noise and some dust. Your heating and hot water will be off from this point until commissioning.

Day 2: Installing the Main Components

Position and mount the outdoor unit on its prepared base
Install the new hot water cylinder in its designated location
Complete the pipework connecting the outdoor unit, indoor unit, cylinder, and existing radiator circuit
Connect the electrical supply to the outdoor unit and controls
Install the system controls (room thermostat, programmer, weather compensation sensor)
Begin filling and pressurising the heating system

Disruption level: Moderate to high. This is typically the busiest day, with engineers working both inside and outside the property.

Day 3: Completing and Testing

Final pipework connections and insulation of all exposed pipes
System flush and fill with inhibitor
Power on and initial system test
Check all radiators are heating correctly and bleed if necessary
Test hot water production and cylinder temperature
Begin commissioning process (see Stage 5)

Disruption level: Lower. Most of the noisy work is done. Engineers are primarily testing and fine-tuning.

When It Takes Longer

Some installations require additional time:

Ground source heat pumps: The ground loop installation (borehole or trench) adds 1 to 3 days before the main installation begins. Borehole drilling is a separate specialist operation. See our ground source heat pump cost guide for details.
Significant radiator upgrades: If multiple radiators need replacing or adding, this can add a day.
Complex pipework routes: Large properties, properties with limited access, or installations requiring extensive pipework modifications take longer.
Electrical supply upgrades: If your property needs a larger incoming supply from the distribution network operator, this can add weeks to the timeline (though the work itself is done separately from the heat pump installation).

For a full breakdown of what different installations cost, see our air source heat pump cost guide.

Stage 5: Commissioning (Half Day to 1 Day)

Commissioning is the formal process of setting up, testing, and certifying that your heat pump system is working correctly. It is a legal requirement and essential for your warranty.

What Happens During Commissioning

Flow temperature optimisation: The engineer sets the weather compensation curve, which automatically adjusts the heating water temperature based on outdoor conditions. Getting this right is crucial for efficiency.
Heating curve calibration: The system is tuned to deliver the right amount of heat at different outdoor temperatures.
Hot water scheduling: Legionella protection cycles, hot water boost times, and immersion backup settings are configured.
System pressure check: Final check that the system holds pressure correctly with no leaks.
Noise measurement: A check that the outdoor unit meets the noise limits specified in the design (42 dBA at the nearest neighbour's window for permitted development).
MCS certification: The installer completes the MCS installation certificate, which is required for your warranty and for the BUS grant payment.
Handover: The engineer walks you through how to use the controls, explains what the different settings do, and answers your questions.

Do Not Rush Commissioning

Commissioning is arguably the most important stage of the entire process. A heat pump that is correctly commissioned will run more efficiently, cost less to operate, and last longer than one where the installer has cut corners. If your installer is trying to complete commissioning in under two hours for a full system, that is a red flag.

A well-commissioned system should be set up for the weather compensation to do most of the work automatically. You should not need to constantly adjust settings. If you find yourself regularly overriding the controls, the commissioning may not have been done properly.

Stage 6: After Installation (First Few Weeks)

The first heating season with a heat pump involves a learning curve for both you and the system.

What to Expect

The system will settle in over the first few weeks. It may take 2 to 3 heating cycles for the weather compensation to fully calibrate to your home.
Your home may feel different. Heat pumps deliver a gentler, more consistent warmth than a gas boiler. Radiators will feel warm rather than hot. This is normal and more comfortable once you adjust.
Monitor your electricity consumption to ensure it aligns with the projections from your installer. Smart meters and heat pump monitoring apps make this straightforward.
Your installer should offer a follow-up visit within the first month to check the system is performing correctly and make any adjustments. Ask about this before you sign the contract.

For guidance on ongoing maintenance and what annual servicing involves, see our heat pump maintenance costs guide.

You can also compare the ongoing costs against your old boiler in our heat pump vs gas boiler guide.

Tips to Minimise Disruption

Time it right. The best time to install is late spring or early summer, when you do not need heating. This gives the system time to be installed, commissioned, and tested before winter. It also means less inconvenience from being without heating during the work.
Combine with other works. If you are already planning insulation upgrades, radiator replacements, or electrical work, doing these at the same time as the heat pump installation reduces overall disruption and can save on labour costs.
Communicate with your installer. Ask for a day-by-day schedule before work begins. Knowing what to expect each day helps you plan around the disruption.
Plan for noise. There will be drilling, hammering, and general construction noise during the installation. If you work from home, plan to work elsewhere on the noisiest days (typically days 1 and 2).
Keep pets and children away from the work area. There will be open pipework, electrical connections, and heavy equipment being moved.

The Overall Timeline at a Glance

Week 1-2: Survey, heat loss calculation, system design, quotation
Week 2-3: Compare quotes, accept preferred installer
Week 3-6: Grant application and approval (if applicable)
Week 6-7: Pre-installation preparation and equipment delivery
Week 7-8: Installation (2-4 days) and commissioning (half to full day)

Total: approximately 4 to 8 weeks from first survey to a fully operational system. The actual time your home is disrupted by installation work is typically 3 to 5 days.

Frequently Asked Questions

Can a heat pump be installed in one day?

It is technically possible for a very simple swap (for example, replacing an existing heat pump with a like-for-like unit), but a full new installation replacing a gas boiler should take at least 2 to 3 days. An installer who promises to complete a full installation in a single day is likely cutting corners on commissioning, which will cost you in reduced efficiency and potentially void your warranty.

Do I need to be at home during the installation?

You do not need to be present for every minute, but someone should be available on the first morning (to provide access and confirm arrangements) and during commissioning (to receive the handover and ask questions). Many homeowners choose to be at home throughout, which is perfectly fine.

How long does a ground source heat pump take to install compared to air source?

Ground source installations typically take 1 to 2 weeks longer due to the ground loop work. A horizontal trench system requires excavation across a significant area of garden and takes 2 to 3 days for the ground works alone. A vertical borehole system requires a specialist drilling rig and takes 1 to 2 days per borehole, plus mobilisation time. The indoor installation work is similar to an air source system. See our ground source heat pump cost guide for the full picture.

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