Air Source Heat Pump Installation
Considering an air source heat pump for your home? Whether you need to understand heat pump costs in the UK, determine your property's suitability, or learn how the technology works, this page provides a comprehensive overview covering everything from installation to the government grants available.
What Is an Air Source Heat Pump?
An air source heat pump is a compact outdoor unit that extracts thermal energy from the ambient air, even at temperatures as low as -25°C, and transfers it into your radiators and hot water system. Unlike a gas or oil-fired boiler, it does not burn any fuel. And unlike conventional electric heaters, it does not simply convert electricity into heat on a one-to-one basis. Instead, it moves existing thermal energy, which is why running costs are significantly lower.
Once operational, the system requires minimal intervention. It runs quietly, maintains consistent comfort throughout the property, and performs reliably even in the coldest UK winters. Air source heat pumps are particularly well suited to the UK climate, delivering efficient heating throughout the autumn and winter months.
Key Benefits of Heat Pump Technology
Up to 500% Efficiency
For every unit of electricity consumed, a heat pump delivers three or more units of heat. No conventional boiler achieves comparable performance.
£7,500 BUS Grant Available
The government's Boiler Upgrade Scheme provides up to £7,500 towards your installation. We manage the entire application process on your behalf.
Significantly Lower Emissions
Switching from gas can reduce your household carbon emissions by approximately 44%, making a meaningful contribution to a cleaner environment.
Engineered to Last 20+ Years
With nothing more than an annual service, a quality heat pump will deliver reliable performance for two decades or longer.
How Air Source Heat Pumps Work
Heat pumps do not generate heat from scratch; they transfer it. There is thermal energy present in outdoor air even at -25°C, and the system captures it. This is why heat pumps achieve over 300% efficiency: 1kW of electricity input produces 3kW or more of usable heat.
Refrigerant circulates through a coil in the outdoor unit, absorbing thermal energy from the ambient air.
A fan draws outside air across the coil, transferring heat energy into the refrigerant liquid.
The refrigerant absorbs sufficient warmth to evaporate, transitioning into a low-pressure gas.
A compressor pressurises the gas, significantly raising its temperature to a usable level.
The superheated gas passes through a condenser inside the property, releasing its heat into the central heating circuit.
An expansion valve reduces the pressure and cools the refrigerant, and the cycle repeats continuously.
Types of Heat Pump System
Air Source
The most widely installed option across the UK. A compact outdoor unit extracts heat from the air and distributes it throughout your property. Suitable for most residential property types, from terraced houses to detached homes.
Ground Source
Pipes buried underground collect heat from the soil. This requires either a borehole or sufficient garden space for trenching, but delivers exceptionally consistent performance throughout the year.
Water Source
These systems extract thermal energy from a nearby water body such as a lake, river, or borehole. While less common for residential use, they offer outstanding efficiency where the geography permits.
Heat Pump FAQs
What is an air source heat pump and how does it work?
An air source heat pump extracts heat from the outside air and uses it to heat your home and hot water. It works like a refrigerator in reverse: a refrigerant absorbs heat from the outdoor air, a compressor raises that heat to a useful temperature, and it is transferred to your radiators, underfloor heating and hot water cylinder. It runs on electricity and burns no fuel on site.
Are heat pumps efficient?
Yes. A gas boiler converts fuel to heat at best one-for-one. A heat pump moves existing heat rather than creating it, so it typically delivers three to four units of heat for every unit of electricity it uses. That ratio is measured as the Seasonal Coefficient of Performance (SCOP), and the figure for your property depends on your system design, flow temperature and how well insulated your home is.
Will a heat pump lower my energy bills?
It depends on what you are replacing.
Households replacing electric storage heaters typically save between £700 and £1,200 a year on heating bills. Savings against a gas boiler are smaller and depend on the age and efficiency of your existing boiler, your electricity tariff and your home's insulation, the Energy Saving Trust estimates around £260 a year against an older G-rated boiler. Against a modern A-rated gas boiler on a standard tariff, running costs may be broadly similar.
We give you a property-specific estimate at survey rather than a headline figure.
Sources and assumptions: figures are indicative annual heating cost savings for a typical UK home, based on Energy Saving Trust guidance. Actual savings depend on your existing heating system and its age and efficiency, your electricity and fuel tariffs, your home's insulation, and how you use your heating. We provide a property-specific estimate at survey.
Are heat pumps noisy?
Modern units are quiet. Under the permitted development rules in England, a heat pump must be assessed to no more than 42 dB(A) at the nearest habitable room window of a neighbouring property, quieter than a normal conversation. We carry out this assessment as part of every survey, and unit siting is chosen to keep noise down at both your property and your neighbours'.
Do I need planning permission?
In most cases, no. Most domestic air source heat pump installations in England fall under permitted development, provided they meet the siting and noise conditions. Since 28 May 2026, MCS 020(a) is the only accepted noise assessment method for permitted development. Rules differ for flats, listed buildings, conservation areas and properties covered by an Article 4 direction. We confirm your property's position before any work is agreed.
Will a heat pump keep my home warm in winter?
Yes. Air source heat pumps extract heat from the air well below freezing and are designed against the coldest expected temperature for your region, not an average. A correctly sized and designed system will hold your home at temperature through a UK winter. Undersizing is the usual cause of a heat pump underperforming in cold weather, which is why the heat loss survey matters more than the badge on the unit.
Do I need to replace my radiators?
Not always, but some usually need upsizing. Heat pumps run at a lower flow temperature than a gas boiler, typically around 45–55°C rather than 70–80°C, so radiators need more surface area to deliver the same heat output. Our heat loss survey calculates this room by room. Many homes need only a few radiators changed, not the whole system.
How much space does a heat pump need?
The outdoor unit sits against an external wall or on a level base with clear airflow around it. Indoors you will need space for a hot water cylinder, usually in an airing cupboard, loft or utility area, a heat pump cannot produce instant hot water the way a combi boiler does, so a cylinder is required. We confirm exact dimensions and siting at survey.
How much does a heat pump cost to install?
| Property Type | Estimated Cost | Cost After Grant |
|---|---|---|
| 1-2 Bed Flat / Apartment | £8,000 - £10,000 | £500 - £2,500 |
| 2-3 Bed Terraced | £9,000 - £12,000 | £1,500 - £4,500 |
| 3 Bed Semi-Detached | £10,000 - £14,000 | £2,500 - £6,500 |
| 4+ Bed Detached | £12,000 - £18,000 | £4,500 - £10,500 |
* Prices are indicative and include VAT. A free home survey will confirm your exact quote.
How do I get the £7,500 Boiler Upgrade Scheme grant?
The Boiler Upgrade Scheme (BUS) provides £7,500 towards the cost of an air source heat pump. As an MCS-certified installer, Casa Renewables handles the entire grant application for you.
- £7,500 off the cost of an air source heat pump
- Available for owner-occupiers in England & Wales
- Property must have adequate insulation (loft & cavity wall)
- Must replace an existing fossil-fuel heating system
- MCS-certified installer required, Casa Renewables is MCS certified
- Grant applied directly, no upfront cost to you
What's included in my quote?
Survey and system design, the heat pump and cylinder, radiator changes identified in the survey, pipework and electrical work from heat pump to cylinder, commissioning, MCS certificate and handover, manufacturer warranty, workmanship guarantee, grant paperwork.
Can I have a heat pump installed during a renovation or extension?
Yes, and it is often the best time to do it. A renovation lets pipework, radiator positions and the cylinder location be designed in rather than retrofitted, and any insulation improvements you are making will lower the heat loss figure and let the system run at a lower flow temperature. Talk to us early so the heating design can be coordinated with your builder.
How long does the installation take?
Our MCS-certified installers complete the full installation, typically within 3-4 working days.
Ready to Discuss Your Heat Pump Installation?
Contact our team for an honest assessment of your property, guidance on available grants including the £7,500 BUS grant and oil-fired boiler replacement funding, and a clear recommendation on whether a heat pump system is the right solution for your home.