Air Source Heat Pump Installation Guide

ground source heat pump grants

Air source heat pumps (ASHPs) are highly beneficial, offering an alternative to traditional gas boilers and providing an opportunity for households to reduce energy bills. But heat pumps can be expensive to install, leading some to perhaps consider installing one themselves.

The reality is that installing an air source heat pump is not something you should undertake yourself, but it is in your best interest to understand a little about the install heat pump process if you’re thinking about changing to this method of renewable heating.

Installing An Air Source Heat Pump – Getting Started

The first key step is finding the best heat pump installers to fit your new air source heat pump, so there will be little stress and your only concern will be learning how to use and get the most out of your new system.

This guide will break down what you can expect when having an air source heat pump installed, especially if replacing a conventional heating system such as a gas boiler, ensuring you have knowledge about all the stages of the installation process.  

Why should a professional be installing your air source heat pump?

Installing an air source heat pump requires a competent professional with a thorough understanding of a number of key areas including low-temperature heating systems, vapour compressors, weather compression and heat pump controls, in order that the system can be set up correctly for best performance and efficiencies.

ASHPs have refrigerant circulated in the compressor and function at low temperatures to optimise their efficiency. They are not devices that can simply be switched on and off like a conventional boiler, so need to be set up correctly to achieve the right level of efficiency and avoid using more electricity than it needs to.

This heat pump will have electrical connections that have to be set up by appropriately qualified electricians as well as plumbing circuits that need to be made by unvented system qualified and experienced installers.

Can you install an air source heat pump yourself?

Installing an air source heat pump is not a job that should be attempted by anybody other than a qualified professional. It is possible that some parts of the pipework could be fitted by a competent DIYer looking to minimise costs, as long as they follow the design laid out by the system designer.

It is also possible that insulation on the pipe can also be added by someone with good DIY skills and experience, but you really should seek advice from a qualified engineer before you attempt any of the installations yourself. Luckily, we pair you with some of the UK’s top air source heat pump installers, so you really won’t need to worry about having to install any of it yourself.

Choosing the right type of air-source heat pump

There are two main types of ASHP you may want to consider:

  • Monobloc systems – these have all the refrigeration components sealed in one unit. So, no refrigerant connections are required to be made on-site, meaning the system can be completely installed by a plumber and electrician. The monobloc unit should preferably be less than 10 metres from the hot water cylinder or underfloor heating manifolds.
  • Split type heat pump – if you need the outdoor unit to be further away from your property or you live in an especially cold climate then this type of pump could be more suitable. A split air source heat pump has half of the heat pump (with the actual fan in it) outside and half of it inside and the two halves are linked together with refrigerant pipes on site.

What size air source heat pump do you need for your home?

The most suitable size air source heat pump that you need for your property can be worked out by your installation design engineer. As with any suitable heat distribution system, the level of heat loss and the hot water requirements of your home needs to be calculated. Additionally, the local weather conditions as well as the design temperature needs of the house are taken into consideration, after which a heat pump will be specifically chosen to cover the load.  

What will your heat pump installer do?

The installer will design and detail the equipment involved in the installation including the heating capacity, where the equipment will be sited, the relevant distribution networks, and the user controls.  Prior to fitting the system, you will be informed what aspects are not included, such as repairing decoration that might be impacted by an installation, particularly in an existing older property. 

Some installers might also be qualified plumbers and therefore able to include other plumbing aspects that could be affected by the ASHP installation. The installer will get your heat pump system up and running and provide clear instructions for how it works. They are also likely to offer maintenance and aftercare support packages. 

What does an air source heat pump look like when it is installed?

Air source heat pumps are outdoor units, but require a controller and potentially two cylinders as indoor units inside the property. The fan unit, typically 1200mm (h) x 1000mm (w) x 400mm (d), will be connected to at least one hot water cylinder.

An extra cylinder (buffer tank) about a third of the size of the hot water cylinder may also be required. Inside, there will be an ASHP control box.

Also, there will be multiple circulation pumps and pipework, as well as a manifold and control box, if the system is being used to supply an underfloor heating system. This is best located in one room that allows enough space for the materials and pipework, but also for easy access for future maintenance or repairs.

How long does the installation of an air source heat pump take?

Depending on how complex the installation is, an air source heat pump could be installed one day. A ground source heat pump can take several days because of the groundwork excavation required. A solid base for the outdoor unit is required, and needs to be in place prior to the installation. 

How much does it cost to install a heat pump?

The cost of installing an air source heat pump in a new or self-build property is expected to be upwards of £11,000. That number will be higher in an older building when you take into account improvements to the home’s fabric and replace and remove existing heating systems. The cost will still be significantly less than ground source heat pumps which are more expensive because of the extensive excavation and groundwork involved with the installation process.

Various schemes aimed at helping households reduce their carbon footprint and energy bills, such as the Boiler Upgrade Scheme, can help by providing grants towards the cost of heat pump installation, but even with the grant, households will still likely have to make a contribution towards the cost of a new heat pump.

What do you need to know after your air source heat pump has been installed?

When your ASHP has been installed you should not have to get too involved as it will already have been commissioned by the installer. All you need to concern yourself with is ensuring you get a proper handover of the system from the installer so that you fully understand how it works and any potential issues. You should not need to change any of the settings, but should only attempt to do so when you are fully competent. 

Does an air source heat pump need a lot of maintenance?

With most heat pumps, the maintenance and check are visual. There are inspections that you can do such as checking that the outdoor unit has free air movement and is not blocked up with leaves or other debris.

Also, you should inspect the pipework to make sure all of the insulation is intact and there are no visible signs of leaks or corrosion on the pipework or casing. However, you will still need to service your central heating system that is likely connected to the air source heat pump.

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Ollie Creevy
Ollie has been writing content online about home improvements for over 3 years. With a real interest and in-depth knowledge of heat pumps and ECO home improvement measures you can use to save on your energy bills. Ollie also keeps up to date with all the Government grants available for you to take advantage of like ECO4 and the Boiler Upgrade Scheme.