Air Source Heat Pump Installation
Air Source Heat Pump Installation in Cardiff and South Wales
CS Boxall design and install air source heat pumps across South Wales, offering a genuine alternative to homeowners facing the cost of replacing an oil, LPG or gas boiler.
We have spent over 40 years fitting and repairing heating systems in this part of Wales, a lot of it on older stone properties and rural homes off the gas grid. That experience matters with heat pumps more than with any other system we install, because a heat pump only performs as well as the heat loss survey, the radiator sizing and the pipework behind it. A heat pump fitted like a boiler swap will disappoint. One that has been properly designed will not.
An air source heat pump takes low-grade heat out of the outside air and upgrades it to a useful temperature for your radiators, underfloor heating and hot water cylinder. It keeps working in the cold, well below freezing, and because it moves heat rather than making it, it delivers around three to four units of heat for every unit of electricity it uses. A gas or oil boiler will never beat one unit in for one unit out.
The trade-off is that a heat pump runs at a lower flow temperature than a boiler. That means it heats your home steadily over longer periods rather than in short blasts, and it means some radiators usually need upsizing to give out the same heat at a lower temperature. Working out exactly which ones is part of the design work, and it is where a properly conducted survey earns its money.
Heat Pump Grants and the Boiler Upgrade Scheme
The Boiler Upgrade Scheme is a UK Government grant, administered by Ofgem, available to homeowners and small business owners in England and Wales. As at July 2026 it pays:
- £7,500 towards an air source heat pump replacing a mains gas or standard electric heating system
- £9,000 for eligible off-gas-grid properties currently heated by oil or LPG, available from 21 July 2026 until 31 March 2027
The higher rate matters a great deal in the Vale of Glamorgan and rural South Wales, where a large number of properties have no gas connection and run on oil. If that describes your home, this is the most generous the scheme has been.
The grant can only be claimed through an MCS certified installer, and it is the installer who applies, not you. It comes off your quote as an upfront discount, so there is no paperwork to chase and no waiting for a rebate. The scheme is confirmed to run to 2030, but grants are issued on a first-come basis within each year’s budget, and the £9,000 uplift is time-limited.
Some Welsh households may also be eligible for support through the Welsh Government’s Warm Homes Nest scheme, which can cover the full cost of an installation for qualifying low-income and benefits-receiving households. You cannot claim both for the same measure, so it is worth checking which route suits you before committing. We can talk you through it.
How We Approach a Heat Pump Installation
Survey and heat loss calculation. We measure the property room by room and calculate its heat loss. This is not an estimate from the floor area. It determines the size of the heat pump, which radiators need changing and what flow temperature the system will run at.
System design. You get a written design showing the proposed heat pump, cylinder, radiator schedule, expected performance and an estimate of running costs, so you can compare it honestly against staying on oil or gas.
Installation. Most installations take three to five days. The outdoor unit goes on a base or brackets against an external wall, the hot water cylinder goes wherever there is space, and we upgrade radiators and pipework where the design calls for it.
Commissioning and handover. We commission the system, set the weather compensation and controls, register the installation, submit your grant claim and then show you how to run it. Heat pumps are operated differently from boilers, and five minutes of proper handover saves a lot of frustration in the first winter.
Aftercare. We service what we install, and we are local, so you are not waiting on a national contractor to send someone from Bristol. If you are a landlord, we can look after the properties in your portfolio too.
We install air source heat pumps for domestic and small commercial clients across South Wales. Some of the areas our engineers frequently cover include:
- Cardiff
- Swansea
- Vale of Glamorgan
- Cowbridge
- Bridgend
- Newport
- Penarth
- Porthcawl
- Port Talbot
- Caerphilly
Our air source heat pump services in South Wales include:
- Room-by-room heat loss surveys and system design
- Air source heat pump supply and installation
- Boiler Upgrade Scheme grant applications on your behalf
- Oil and LPG boiler replacements for off-grid properties
- Hot water cylinder installation and upgrades
- Radiator upsizing and replacement
- Underfloor heating design and installation
- Pipework upgrades and system flushing
- Weather compensation and smart control setup
- Buffer tanks and volumisers where required
- Annual heat pump servicing and maintenance
- Performance checks and fault finding
- Advice on solar PV pairing and off-peak tariffs
- Small commercial and light industrial installations
FAQs
Frequently Asked Questions
How much does an air source heat pump cost to install?
A typical domestic installation costs in the region of £10,000 to £16,000 before grant funding, depending on the size of the property and how much radiator and pipework upgrading is needed. After the Boiler Upgrade Scheme grant is deducted, most homeowners pay considerably less. Contact CS Boxall for a fixed quote following a survey.
Am I eligible for the £7,500 heat pump grant?
You need to own the property, it must be in England or Wales, and you must be replacing a fossil fuel system such as gas, oil or LPG, or a standard electric system. Hybrid setups that keep a gas boiler running alongside the heat pump do not qualify. One grant per property. The installation has to be carried out by an MCS certified installer. We will confirm your eligibility as part of the survey.
Do air source heat pumps work in cold weather?
Yes. They continue to extract heat from the air well below freezing, and they are used as standard across Scandinavia. Output does reduce as the outside temperature drops, which is exactly why the system is sized against your property’s heat loss on a design cold day rather than an average one.
Will I need to replace all my radiators?
Usually not all of them. Because a heat pump runs at a lower flow temperature, some radiators need to be larger to give out the same heat. In most homes that means changing a handful rather than the whole lot. The survey tells you precisely which ones, in writing, before you commit.
Are air source heat pumps cheaper to run than an oil boiler?
For most off-grid properties, yes, particularly on a heat pump friendly electricity tariff. A well-designed system delivers around three to four units of heat per unit of electricity, and it removes the need for oil deliveries and price volatility. We include a running cost estimate for your specific property in the design.
Do heat pumps work in older Welsh properties?
They can, and we have plenty of experience with the local housing stock. Solid wall properties have higher heat loss, so they need a larger unit and more attention to radiator sizing, and improving insulation first will always help. What matters is that the design reflects the building you actually have rather than a standard assumption.
How long does a heat pump installation take?
Most installations take three to five days on site. Where extensive radiator and pipework upgrades are needed, allow up to a week. Design and grant paperwork happen before we start, so the disruption is limited to the install itself.
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