How an air source heat pump works
An air source heat pump draws heat from outdoor air, even on cold days, and raises it to a useful temperature with a compressor, in the same way a fridge works in reverse. It feeds your radiators or underfloor heating and heats a hot water cylinder.
Because it moves heat rather than burning fuel, a well-designed system delivers several units of heat for every unit of electricity it uses. How efficient it is in practice depends on good design, sensible flow temperatures and how well the home holds its heat.
What gets installed
- 1
Heat loss survey
A room-by-room calculation that sets the size of the heat pump and shows which radiators need upgrading.
- 2
Outdoor unit
Mounted on a base or wall brackets, with clearance for airflow. Its position is checked against permitted development and noise rules.
- 3
Hot water cylinder
Most combi-boiler homes need space for a cylinder, often where an old one used to be or in a cupboard.
- 4
Radiator and pipework upgrades
Larger emitters where needed, plus controls, a buffer or volumiser if the design calls for one, and system flushing.
- 5
Commissioning and handover
The system is set up for your home, explained to you, and certified for your records and any future house sale.
What drives the cost of a heat pump
Heat demand
Larger or draughtier homes need a bigger unit. Insulation upgrades can reduce the size you need.
Radiator upgrades
The number of rooms that need larger radiators is one of the biggest variables.
Hot water cylinder
The cylinder size and where it goes, especially in homes moving from a combi boiler.
Property type
Solid stone walls, tenements and older cottages each bring different design challenges.
Old system removal
Removing an oil tank, LPG tanks or an old boiler and flue adds to the work.
Location
Rural and island jobs can involve extra travel and logistics, and are reflected honestly in quotes.
Paying for your heat pump
You can pay upfront or spread the cost. Interest-free credit up to £30,000, subject to status. We will explain the available options during your no-obligation survey, so you can compare paying upfront with spreading the cost. You are never obliged to take finance, and you can always ask for a quote without it.
Your quote shows the full price of the installation with no hidden extras. Take it away and decide in your own time, with no pressure to proceed.
Common questions
Do heat pumps work in a Scottish winter?
Yes. Modern air source heat pumps are designed to keep heating well below freezing and are widely used in colder countries than Scotland. Performance depends on correct sizing and design, which is why a proper heat loss calculation room by room matters far more than the brand you choose.
Will I need new radiators?
Sometimes. Heat pumps run at lower flow temperatures than boilers, so some rooms may need larger radiators to stay comfortable. The heat loss survey shows exactly which rooms need upgrading. Many homes keep most existing radiators and replace only a few, while underfloor heating suits heat pumps very well.
How efficient is a heat pump?
A well-designed air source heat pump moves heat rather than burning fuel, so it delivers several units of heat for every unit of electricity it uses. Efficiency depends on good design, sensible flow temperatures and how well your home holds its heat. A proper room-by-room heat loss calculation is the key to getting this right.
Can a heat pump replace an oil or LPG boiler?
In most cases, yes, and off-gas homes are often where heat pumps make the strongest case. The survey checks insulation, radiator sizes and space for a hot water cylinder. Once the switch is made, the oil tank or LPG bottles can usually be removed, freeing up outdoor space.
Last updated: 17 October 2026