What to Expect During a Heat Pump Installation
- Leah Robson
- Apr 1
- 6 min read
Updated: Apr 2
If you’re planning ahead, it helps to understand what to expect during a heat pump installation, so there are no surprises along the way.
The most important headline is that jobs take 1 - 2 weeks and you should plan to be without heating for the majority of this time. However, please speak to our Senior Engineer when you have your technical site visit, because depending on your current setup it is sometimes possible to shorten this outage.
Hot water is a different matter, and we normally get the hot water back on within a day.
Our engineers will always work hard to ensure that your home is left tidily each evening so that we minimise disturbance as much as possible.
There are three main parts to the installation, which may happen in different orders depending on your house setup and what works best for you: upgrading radiators, installing the cylinder, and fitting the outdoor unit.
Upgrading your Radiators
If your home needs larger radiators, we’ll remove the old ones and install new ones - this is a straightforward process. We’ll also replace all radiator valves, even if the radiator itself isn’t being changed. This ensures everything is a high-quality product with a good bore that won’t restrict flow. More about this here: TRVs and Heat Pumps: What You Need to Know (and Why We Often Take Them Out)
Replacing a radiator typically takes 2-3 hours, while changing a valve takes about 45 minutes. It can be a little noisy, so we recommend staying in another room while this work is happening. If you have calls during the day, just let us know - we’re happy to work around your schedule.
We’ll need access to every radiator, so it’s helpful if there’s clear space around each one. This space should stay clear until the system is fully filled and checked for leaks, so it’s best to leave things as they are until the end of the day.
This is also when any pipework upgrades take place. New radiators may be a different size, so adjustments to pipework is sometimes needed. In some cases, we may need to lift carpets or floorboards - especially if you’d like pipework to run neatly from the floor to the radiator.
If you’re happy for pipework to be adjusted above the floor, we can usually avoid lifting floorboards. This is quicker, and we’ll always keep things as neat as possible. If we do need to lift flooring, we’ll always put it back by the end of the day. We know this part of the heat pump installation process can feel disruptive, so we aim to leave your home tidy and comfortable each evening.
This blogpost has more detail about when and why we replace radiators - Do I need to upgrade my radiators for a heat pump?
Installing the Cylinder
On the majority of installs we’ll remove your old cylinder and install a new one designed to work efficiently with a heat pump. You won’t have water (hot or cold) for most of the day while this work is carried out, but don’t worry, we’ll always make sure cold water is restored by the end of the day. Very occasionally, hot water may be unavailable overnight, but we’ll let you know in advance if that’s likely.
When your hot water returns, it will initially be heated by the immersion heater rather than the heat pump, so it may be hotter than usual - please take care to avoid scalding.
We’ll also install additional components near the cylinder to ensure everything runs safely and efficiently. Ideally, we recommend a space of around 600mm x 1200mm for the cylinder, although this depends on your current setup.
Fitting the Outdoor Heat Pump Unit
Heat pumps can be put directly onto a hard surface, or on a purpose built base. Either way, there must be drainage for the condensate water that drips out whilst the unit is running. Often the first part of the install is to build a base for the heat pump.
Another piece of work that can happen before the main installation, an electrician will install a dedicated power supply for the heat pump. They’ll need access to your fuse board (consumer unit). This can take anywhere from a couple of hours to a full day, depending on how complex the cable route is and will involve a short electrical outage.
Once the heat pump is delivered, our engineers will position it where it needs to go. From there, we’ll begin making the plumbing and electrical connections. This involves drilling two holes in your outside walls to run pipework between the outdoor unit and the cylinder, followed by installing all the necessary connections.
Final installation of the outdoor unit typically takes around two days from start to finish.
How your Heat Pump Installation Comes Together
Different parts of the installation often happen at the same time. For example, an apprentice might be working on radiators while an engineer installs the cylinder.
For a typical retrofit, the work will typically take 1 - 2 weeks. This will vary depending on the size and complexity of your home. Throughout the project, you’ll get a clear picture of what to expect during a heat pump installation and how each stage fits together.
You can expect at least one engineer and one apprentice on site each day, with additional team members joining when needed.
What Else Happens During the Installation?
A few other important steps take place during the installation:
Most likely, on the first day, your boiler will be turned off for the final time. We’ll briefly run it to check all radiators are working, then remove it.
We will cap the gas supply safely for you if you are moving away from gas completely.
You won’t have central heating during the installation, but we’ll provide portable electric heaters to keep you comfortable.
Once the new radiators and cylinder are installed, we’ll flush the system to remove any debris.
The system is then drained and refilled with purified water to help protect it and maximise its lifespan. You can read more about this here: Who Cares About the Water in your Radiators? We do and Here's Why.
Wiring the heat pump up so that the thermostat and valves and pumps all work as and when they should is one of the final stages, along with entering all the right settings for maximum comfort and efficiency.
Finally, we’ll run a series of tests to make sure everything is working as it should.
That's a Wrap!
And that’s it - installation complete! Well, almost.
Once everything is in place, we will leave it running and bedding in for a few days before a Senior Engineer will carry out full commissioning of the system and walk you through how everything works.
You’ll look at the controls together to make sure your home is comfortable and running efficiently and we'll take about maintenance and support options going forward Heat Pump & Solar Servicing & Aftercare
Then it’s well and truly over to you, to enjoy your new, low carbon heating system!
Thinking about installing a heat pump in your home? Get in touch with our team for expert advice and a no-obligation estimate - we’re here to help you every step of the way.
What others say:
Read our customer reviews
Heat pump installation FAQs
How long does a heat pump installation take?
Most heat pump installations take around 7 days for a typical home. However, this can vary depending on the size of the property and how much work is needed, such as upgrading radiators or pipework.
Will I be without heating during installation?
Yes, your existing heating system will be turned off during the installation. We provide portable electric heaters to keep you comfortable while work is ongoing.
Will I have water during the installation?
You may be without water (both hot and cold) for part of the day while the cylinder is being installed. However, we’ll always make sure cold water is restored by the end of the day, and we’ll let you know in advance if hot water will be unavailable overnight.
Do I need new radiators for a heat pump?
Not always - but many homes do require larger radiators to work efficiently with a heat pump. We’ll assess your current system and let you know what’s needed.
Is heat pump installation disruptive?
There is some disruption, including noise and access to different areas of your home. Occasionally, floorboards or carpets may need to be lifted. We always aim to keep things as tidy as possible and leave your home comfortable at the end of each day.
Will someone show me how to use the system?
Yes, once the installation is complete, a Senior Engineer will fully commission the system and walk you through the controls, so you feel confident using your new heating system.
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