Heat Pump vs Gas Boiler: Which Is Better for Your Home?
If you have a gas boiler, it is reasonable to ask whether replacing it with a heat pump would make your home more comfortable or reduce your energy use. The answer depends partly on what you mean by “heat pump”. Some systems heat water for radiators; others warm the air in individual rooms.
That distinction matters. TotalTemp Control installs air-to-air heat pumps, also known as reverse-cycle air conditioning. They can provide heating and cooling, but they do not heat your domestic hot water. They are not a like-for-like replacement for a boiler that serves radiators and taps.
This guide explains the differences between the main air source heat pumps UK homeowners may consider, and where each could make sense.
Why more homeowners are comparing heating options
The UK is moving towards lower-carbon heating, and government support schemes have brought heat pumps into wider discussion. The Boiler Upgrade Scheme may help eligible property owners with some installation costs. Its rules and support can change, so check the current GOV.UK guidance and Ofgem information before making plans.
At the same time, homeowners may have heard conflicting claims about heat-pump performance, installation costs and running costs. A useful starting point is to compare the system’s function with what your home actually needs, rather than assuming every heat pump replaces a boiler in the same way.
How boilers and heat pumps provide warmth
A gas boiler burns gas to heat water. That hot water circulates through radiators or underfloor heating, and a combi boiler can also provide hot water directly. In a system boiler setup, hot water is generally stored in a cylinder.
A heat pump works differently. It uses a refrigerant circuit to collect heat from outdoor air and transfer it indoors. It moves heat rather than creating all of it by burning fuel. The type of indoor equipment determines how that heat reaches your rooms and whether the system can also produce hot water.
Air-to-water and air-to-air are not the same
This is the distinction many comparisons overlook. Air-to-water heat pumps heat water for a wet central-heating system. Air-to-air heat pumps heat the air in rooms directly, often through wall-mounted indoor units.
| Feature | Air-to-water heat pump | Air-to-air heat pump |
|---|---|---|
| What it heats | Water for radiators or underfloor heating | Air in the rooms served by indoor units |
| Domestic hot water | Can heat a hot-water cylinder | Does not provide domestic hot water |
| Cooling | Not generally a cooling system for standard radiator circuits | Can provide cooling as well as heating |
| Indoor equipment | Radiators or underfloor heating, plus associated water system | Wall-mounted or other air-delivery indoor units |
| Typical use | Potential whole-home replacement for a wet heating system | Heating and cooling selected rooms or zones |
| Maintenance | Heat-pump and wet-system checks; requirements vary | Filter care and professional system checks; refrigerant work must be done by appropriately qualified personnel |
An air-to-water system is the type to explore if you want one heat pump to serve your home’s radiators and hot water. An air-to-air system can be a useful option for room-by-room heating and cooling, but it does not take over the hot-water role of your boiler.
For a more detailed introduction to reverse-cycle systems, see our guide to air conditioning vs air source heat pumps.
Efficiency depends on the system and the home
A heat pump can deliver more heat energy than the electricity it uses because it transfers heat from outdoors. A gas boiler burns fuel and loses some energy through the combustion process and heat distribution.
For heat pumps, SCOP means Seasonal Coefficient of Performance. It describes the relationship between the heat supplied and electricity used over a heating season. A higher SCOP indicates more heat delivered for the electricity consumed under the conditions used to calculate that rating. It is not a promise of the exact result in a particular home.
Real-world performance depends on factors such as the system model, correct sizing, installation quality, insulation, outdoor conditions and how the controls are used. In an air-to-water system, the water temperature required by radiators also matters. Systems designed to heat water to lower temperatures may perform differently from those that need hotter water.
Air-to-air systems deliver heat directly into room air, so they do not have the same radiator-water temperature requirement. Their performance still depends on the property, selected equipment and how it is operated. For either type, ask for system-specific performance information rather than relying on a headline figure alone.
Running costs are a comparison, not a guarantee
Whether a heat pump costs less to run than a gas boiler depends on the unit prices for electricity and gas, the home’s heat demand, system efficiency and the way you use the heating. The installation cost and maintenance requirements also affect the overall financial picture.
Room-by-room control can change the comparison. With zoned heating and cooling, an air-to-air system can heat the rooms you use without necessarily conditioning every space in the same way. A boiler with radiators may heat several rooms together, although controls and radiator valves can also allow some zoning.
The best comparison is based on your household’s actual habits and the areas you want to heat. Be cautious of any estimate that assumes one set of savings or running costs will apply to every property.
Hot water is the key air-to-air limitation
A gas boiler can provide hot water for taps and showers, either directly or through a cylinder. An air-to-water heat pump can also heat a cylinder as part of a suitable system. An air-to-air heat pump does not heat domestic hot water.
Homeowners who choose air-to-air for room heating and cooling typically keep their existing boiler or use a separate electric water-heating arrangement for hot water. This can be practical where the boiler still works and the main issue is a room that is hard to heat, or a home that overheats in summer.
Keeping a boiler for hot water while adding air-to-air heating is not the same as replacing the boiler with a complete air-to-water system. It is a different arrangement, and the right design depends on how your home is used.
Which option might suit your home?
| Your situation | Option to explore |
|---|---|
| You want to replace an older boiler and heat radiators and hot water through one system | Air-to-water heat pump |
| Your boiler works, but a bedroom, office or conservatory is uncomfortable | Air-to-air heat pump for the rooms that need attention |
| You want targeted room heating and cooling in summer | Air-to-air heat pump with suitable room-by-room controls |
| You are planning a whole-home heating change and have no mains gas connection | Compare air-to-water and other heat-pump options against the home’s needs |
| Your home has suitable insulation and you want heating and cooling in selected spaces | Air-to-air may be worth considering |
A home air conditioning unit can be more than a cooling appliance. A reverse-cycle model can also provide heat, air movement and filtration. If you are considering a ducted air conditioning home system, a survey can establish whether the layout and required coverage are suitable; ducted and room-unit designs are not interchangeable in every property.
For more on selecting a domestic system, read our home air conditioning buyer’s guide.
Check the home as well as the equipment
Insulation and draughts affect how much heat a home loses. Loft insulation, glazing, gaps around doors and windows, and the way rooms are used can all influence the system required. A heat pump may have to work harder in a home with high heat loss, so improving the building fabric may be worth considering before choosing equipment.
For an air-to-water system, heat pumps often operate with lower water temperatures than traditional boiler systems. Some existing radiators may not provide enough heat at those temperatures, so a design may call for larger radiators or other changes. An air-to-air system delivers warm air directly to rooms, so it does not have that radiator-water constraint.
Sizing matters for both types. A professional assessment should consider room size, insulation, glazing, solar gain, occupancy and the areas you want to heat or cool.
Practical points before installation
An outdoor unit needs a suitable position with enough space for airflow and access for future servicing. Consider the unit’s sound rating and location in relation to your own rooms and neighbouring properties. A survey can identify siting options and any practical constraints.
Planning rules depend on the property and where it is located. Some domestic installations may be permitted development, subject to conditions, but listed buildings, conservation areas and other restrictions can affect what is allowed. Check with your local authority and, where relevant, consult the applicable planning rules for domestic heat pumps in England.
Installation work can involve fitting the outdoor and indoor units, connecting services and making good any affected areas. The amount of disruption depends on the system and property. Air-to-air systems also need routine attention to filters and professional maintenance. Work on refrigerant circuits must be carried out by people with the appropriate qualifications; see the GOV.UK guidance on F-gas qualifications.
Frequently asked questions
Are heat pumps cheaper to run than gas boilers?
They can be, but it depends on electricity and gas tariffs, seasonal performance, the home’s heat demand and how the system is controlled. A property-specific estimate is more useful than a general claim.
Can a heat pump replace my boiler?
An air-to-water system may be designed to provide space heating and hot water in place of a boiler. An air-to-air system cannot provide hot water, so it is not a like-for-like boiler replacement.
Do heat pumps work in cold weather?
Air-source heat pumps can extract heat from outdoor air in cold conditions. Their efficiency can reduce as the outdoor temperature falls, so design, sizing and the home’s heat demand matter. The Energy Saving Trust’s heat-pump guidance explains more.
Do I get a grant?
Government support may be available for some installations, subject to the current scheme rules and the property and system meeting its requirements. Check the latest Boiler Upgrade Scheme guidance before relying on a grant in your budget.
Can a heat pump cool my home?
Air-to-air heat pumps can provide cooling as well as heating. Air-to-water systems designed for radiators are generally considered for heating and hot water, not room cooling in the same way.
Do I need planning permission?
It depends on your property, the proposed location and local rules. Check with your local authority before proceeding, especially if your home is listed or in a conservation area.
How long do heat pumps last?
There is no single lifespan that applies to every system. Product choice, installation, use and maintenance all affect service life. Ask about the specific equipment, warranty and recommended maintenance when comparing proposals.
So, which is better for your home?
There is no universal winner. A gas boiler is a whole-home wet heating and hot-water solution. An air-to-water heat pump may be an option for replacing that arrangement. An air-to-air heat pump offers zoned heating and cooling for the rooms it serves, but leaves hot water to another system.
In some homes, keeping a working boiler for hot water while adding air-to-air heating and cooling to selected rooms may be the more practical approach. In others, a whole-home heating change may be the priority.
TotalTemp Control provides domestic heat-pump and air-conditioning surveys across Northamptonshire and surrounding areas, including Corby, Kettering, Northampton, Peterborough, Leicester, Milton Keynes and Bedford. If you are considering air conditioning installation in Northampton or nearby, a tailored survey can help establish what suits your rooms and priorities. You can contact us to book a survey, with no assumption that replacing your boiler is the right answer.