Glossary · Heat pumps, grants and regulations
What is a hybrid heat pump?
A hybrid heat pump is a heating system that pairs an air source heat pump with a gas boiler. A controller chooses which one runs, based on the outside temperature or the cost of electricity against gas. The heat pump covers most day-to-day heating and the boiler steps in when it is very cold.
Key points
- A hybrid system is an air source heat pump backed up by a gas boiler, with a controller choosing between them.
- Worcester Bosch says the heat pump is expected to generate heat 70 to 80 percent of the time, with the boiler topping up in colder months.
- Worcester Bosch puts a hybrid installation at roughly £5,000 to £8,000, lower if the heat pump is added to an existing boiler.
- You cannot get a Boiler Upgrade Scheme grant for a hybrid system, only for a heat pump that replaces the fossil fuel boiler.
- Work on the gas boiler side must be done by a Gas Safe registered engineer.
How a hybrid heat pump works
A hybrid heat pump is an air source heat pump backed up by a gas boiler.[1]Daikin UK, What is a hybrid heat pump? The heat pump uses electricity to draw heat from the outside air. The boiler is the back-up. A controller decides which one to use, based on the outside temperature or on the price of electricity against gas.[1]Daikin UK, What is a hybrid heat pump?
Worcester Bosch says the heat pump is expected to generate heat for 70 to 80 percent of the time. In colder months the boiler acts as a top-up.[6]Worcester Bosch, Hybrid Systems Daikin describes three modes: heat pump only at moderate outdoor temperatures, both running together, and gas only when it turns very cold.[1]Daikin UK, What is a hybrid heat pump? Worcester Bosch adds that most hybrid systems use an air source heat pump because it costs far less to install than a ground source system.[2]Worcester Bosch, Hybrid Heating Systems
The parts of a hybrid system
| Part | What it does |
|---|---|
| Outdoor heat pump unit | Takes heat from the outside air and passes it into the heating water |
| Gas boiler | Tops up the heat in cold weather |
| Controller | Switches between the two, or runs both together |
| Radiators or underfloor heating | Share the same heating circuit as before |
Heat pumps work best at steady, low temperatures. That suits underfloor heating well, but Worcester Bosch says radiators work too, as long as they are the right type and size.[2]Worcester Bosch, Hybrid Heating Systems For more on why low temperatures matter, see flow temperature.
The boiler half is a gas appliance. Anyone employed to work on gas appliances in a home must be Gas Safe registered and competent for that type of work.[5]Health and Safety Executive, Domestic gas: frequently asked questions HSE advises that gas appliances, flues and pipework are installed, maintained and serviced at least annually by a Gas Safe registered engineer.[5]Health and Safety Executive, Domestic gas: frequently asked questions If you are weighing up a new boiler installation alongside a heat pump, ask the engineer to explain which parts are gas work.
Example
Priya lives in a 1950s semi in Bradford. Her gas boiler still works, but she wants to use less gas without rebuilding her whole heating system. She asks about a hybrid.
Worcester Bosch estimates a hybrid installation at between £5,000 and £8,000. It says that if you are adding a heat pump to an existing boiler set-up, as most people do, the cost could be at the lower end of that range.[3]Worcester Bosch, Hybrid Heat Pump Cost The final figure depends on whether the heat pump can sit near the boiler and whether the existing hot water cylinder suits the system.[3]Worcester Bosch, Hybrid Heat Pump Cost Priya gets a survey first, because each system needs designing for the home.
What people get wrong
The most common mistake is to assume a hybrid qualifies for the Boiler Upgrade Scheme. It does not. A gas boiler combined with an air source heat pump gets no grant.
The government page says you cannot get a grant for a hybrid heat pump system.[4]GOV.UK, Apply for the Boiler Upgrade Scheme It is for replacing a fossil fuel system with a heat pump or biomass boiler, and it needs an MCS certified installer.[4]GOV.UK, Apply for the Boiler Upgrade Scheme See boiler grants and MCS certification for how that works. A hybrid is also not a way to avoid gas altogether. The boiler stays in the system, so it still needs its annual service.
The bottom line
A hybrid heat pump keeps your gas boiler and adds an air source heat pump that does most of the everyday heating. It can suit a home that is not yet ready for a heat pump on its own, but it brings no Boiler Upgrade Scheme grant and you still own a gas appliance that needs servicing. Ask for a survey and a quote that compares a hybrid with a standalone heat pump and a new boiler.
Common questions
Can I get a grant for a hybrid heat pump?
No. The government's Boiler Upgrade Scheme page says you cannot get a grant for a hybrid heat pump system, for example a gas boiler combined with an air source heat pump.
How much of the heating does the heat pump do in a hybrid system?
Worcester Bosch says the heat pump is expected to generate heat for 70 to 80 percent of the time, with the boiler acting as a top-up in colder months. The share depends on the home and the settings.
Does a hybrid system still need a boiler service?
Yes. The boiler is still a gas appliance. HSE advises that gas appliances, flues and pipework are installed, maintained and serviced at least annually by a Gas Safe registered engineer.
Is a hybrid heat pump cheaper to install than a heat pump alone?
Worcester Bosch says installing a hybrid is cheaper than switching to a heat pump only solution, and that adding a heat pump to an existing boiler could land at the lower end of its £5,000 to £8,000 estimate.
Sources
We cite the original source for every figure: government, regulators, standards bodies and manufacturers' own documents. Each one shows the date we last checked it.
- Daikin UK. What is a hybrid heat pump?. Checked 11 November 2026. ↩
- Worcester Bosch. Hybrid Heating Systems. Checked 11 November 2026. ↩
- Worcester Bosch. Hybrid Heat Pump Cost. Checked 11 November 2026. ↩
- GOV.UK. Apply for the Boiler Upgrade Scheme. Checked 11 November 2026. ↩
- Health and Safety Executive. Domestic gas: frequently asked questions. Checked 11 November 2026. ↩
- Worcester Bosch. Hybrid Systems. Checked 11 November 2026. ↩