Hybrid Heating Systems Re January 23, 2023

Hybrid Heating Systems

hybrid heating system located in the garden

More and more of us are making changes to protect the environment, and as a result, we’re seeing an increase in the number of homes in the UK trying to actively reduce their carbon footprint. This could be by embracing simple steps, such as reusing shopping bags, walking instead of driving, or taking part in Veganuary (although, not having cheese for a month is a struggle!).

According to The Energy Saving Trust, “The majority of household CO2 emissions come from heating (including generating hot water). Energy Catapult Analysis shows that in 2017, the average household generated 2,745 kg of CO2 emissions from heating, which is around 31% of the total.” 

Given the statistics, the Committee for Climate Change called for a ban on gas boilers in new build domestic homes by 2025, in order to reduce carbon emissions. It’s worth noting that this policy only applies to new builds, not to older properties. The aim of the policy is to reduce the reliance on fossil fuels in the construction and heating industry, but with 85% of UK homes connected to the gas grid, there is a lot of work to do ahead of the ban and a lot of innovation required to achieve it. By 2050, the UK has a goal to reduce carbon emissions by 80%, a difficult challenge to say the least.

Nowadays, we are seeing a trend of growing greener heating options that are powered by non-fossil fuel sources such as wind and solar, meaning that more UK homes will reduce their carbon footprint in the near future.

While these eco-heating options are great for the environment, some of them are either expensive to install and run and/or fail to satisfy peak heating loads on the coldest days. That has led many homeowners planning to stick with gas boilers and has introduced the concept of “hybrid heating”.

What is a hybrid heating system?

A hybrid heating system (also known as a dual fuel heating system) combines a traditional (gas, oil or LPG) boiler with a renewable heating system. It’s the perfect option for those who are looking to invest in more sustainable heating solutions without compromising on warmth. It gives homeowners peace of mind as it combines the familiarity and reliability of the traditional boiler with the sustainability of an air source heat pump. It also reduces your energy bill by alternating between both systems (the boiler and heat pump) based on which will deliver the best energy efficiency at the time – not forgetting that it helps reduce your reliance on fossil fuels.

How does a hybrid heating system work?

Since a hybrid heating system combines both gas boilers with heat pumps, let’s start by explaining the types of heat pumps and how they work.

There are two types of heat pumps available in the market; air source heat pumps (ASHPs) and ground source heat pumps (GSHPs) – and the only difference is where they get their heat from.

Air source heat pumps extract heat from the air, but ground source heat pumps extract heat, (you guessed it), from the ground.

A heat pump captures energy from the outside air and the ground before transferring it into your home to provide you with heating and hot water.

Heat pumps transfer this energy into a fluid, then compresses it to increase its temperature. This warmth is then transferred from the compressed fluid into your central heating system. 

Think of it as reversed air-con, or a backwards fridge!

Something to bear in mind is that during the process, heat pumps use a small amount of electricity to run, making them relatively more efficient to operate than other heating systems but still not 100% carbon neutral.

Generally speaking, hybrid heating systems include air source heat pumps (ASHPs) as they’re easier to install, less disruptive to your garden and relatively cheaper than ground source heat pumps (GSHPs).

A hybrid heating system is smart in operation, it will switch between the heat pump and boiler based on the most efficient option at the time, saving you energy and money. It monitors the outside temperature before making the switch. When the temperature drops below a certain level, the system will heat your home and provide hot water using your boiler. Alternatively, when the outside temperature rises above 2°C, the system will switch to the heat pump. The automated switches will ensure that you only use your boiler when needed which will reduce your carbon footprint and save you money in the long run without compromising on the heating output.

The cost of installing a hybrid heating system

Fitting a hybrid heating system can cost as much as fitting a heat pump and a boiler, which is often an extortionate amount. Although you might be able to save on shared pipework, you’ll spend that on controls and valves.

Some hybrid heating product ranges start from £8,000 upwards. It can cost up to £20,000 depending on the location of the pipework and the changes that will be required to the pipework and the radiator sizes.

It’s fair to say that hybrid heating systems are still not affordable for the vast majority of homeowners in the UK at current prices, especially when you compare this to a gas combi boiler, which costs between £1,500 – £3,000 (including installation) when purchased through WarmZilla.

Although the price is still expensive (3x more than an average gas boiler), you must look at the bigger picture to understand the financial returns. There are three things you’ll have to bear in mind before making the switch to a hybrid heating system;

  • A hybrid heating system will reduce your heating bills by 13%.
  • Your heating system will certainly last longer as there will be less reliance on your standard boiler. On average, a standard boiler could last up to 10 years depending on the boiler brand and how well it has been maintained. With a hybrid heating system, you are unlikely to need a new one for at least 10-15 years.
  • You might be eligible for the Government’s Renewable Heat Incentive (RHI) which will grant you money towards installing and running a renewable heating system. 

Renewable Heat Incentive for installing a hybrid heating system

If you install a heat pump (either a ground source or air-to-water source) as part of your hybrid heating system, you could be entitled to the government’s Renewable Heat Incentive (RHI) scheme.

This scheme provides payments to the owners/occupiers of eligible properties who install and use renewable energy systems to heat their homes. It encourages homeowners to reduce their carbon footprint by relying on renewable heating solutions to heat their homes. 

As a homeowner with a renewable heating system, you’ll receive quarterly payments over 7 years based on the amount of renewable heat produced by your heating system. For more information, check out the Domestic Renewable Heat Incentive page.

Renewable Heat Incentive (RHI) rates

The rates for domestic RHI tariffs for applications submitted between 1 April 2020 and 30 September 2020 are;

RHI technology

RHI tariff

Air-source heat pumps


Ground-source heat pumps 


To put this into perspective; these are the estimated total RHI payments over seven years*


1-bed semi-detached

2-bed semi-detached

3+ bed detached

Air-source heat pump




Ground-source heat pump 




*Estimated RHI payments over the seven-year period are based on estimated payments, calculated by multiplying the average annual heat demand by the relative RHI rate for the different technologies. Source: Which.co.uk

Hybrid heating pros and cons

  • Reduced heating bills
  • More energy efficient 
  • Reliable
  • Longer lifespan 
  • Lower carbon emissions
  • Financial support through the Government’s RHI scheme
  • High installation costs
  • Not completely carbon neutral
  • You will only start seeing savings in the long run
  • Ground-source heat pump installation is disruptive to your garden
  • Heat pumps can be noisy. 

How do you maintain a hybrid heating system?

As the hybrid heating system has two main parts (the boiler and heat pump), the two are serviced differently.

A) Boiler service

The boiler will require annual servicing by a registered Gas Safe engineer.

In the same way that a car has to pass an MOT to keep it roadworthy, you can think of an annual boiler service in the same way – it’s a safety check to make sure it’s all working properly and by getting it checked regularly you can catch small issues before they turn into major issues. This could save you money on costly repairs or even replacement but it also gives you peace of mind that your boiler is safe.

Additionally, if you have a warranty with your new boiler then every manufacturer will insist that an annual service must be carried out and recorded by a relevantly qualified person to satisfy the warranty. The absence of a service history can completely void the warranty on your boiler.

The cost of annual boiler services will vary depending on who carries it out and what kind of boiler you have, but on average the cost will be between £75 – £150 for a local heating company.

B) Heat pump

Although heat pumps require little maintenance, they still need to be checked annually just like any heating system. In fact, the difference between the energy consumption of a well-maintained heat pump and a severely neglected one ranges from 10% to 25%. So having laid out thousands in setup costs, it’s definitely something you want to keep up to date. The annual maintenance cost for an air source heat pump is between £150 – £200.

The best hybrid heating systems in 2022

Daikin Altherma

Daikin Altherma hybrid heat pump combines renewable air-to-water heat pump technology with a gas condensing boiler, to ensure the highest efficiency. Its smart programming helps to save up to 35% more energy than a traditional condensing boiler by automatically determining the most economically and energy-efficient combination based on energy prices, outdoor temperatures and indoor heat capacity.

The Daikin Altherma hybrid heat pump is ideal for renovations and replacing old boilers. Its compact design requires minimal installation space and integrates seamlessly with your existing piping and radiators. This way, you can enjoy the energy efficiency of a heat pump without having to replace your entire system.

The Daikin Altherma hybrid heat pump system is available in two different configurations. In a true hybrid configuration, the system automatically selects the most efficient mode of operation, choosing between the heat pump or gas boiler, or a hybrid operation of the two. So it offers the perfect balance between the gas boiler and the heat pump to provide your home heating and hot water. Alternatively, the Daikin Altherma hybrid outdoor unit can be paired with your existing boiler (or a boiler from another manufacturer) as a ’bi-valent’ system so you can switch between the heat pump or the boiler, but not run both in hybrid operation.

Vaillant aroTHERM

If your main focus is to save energy and reduce your home’s carbon emissions, look no further.

The Vaillant aroTHERM hybrid is a smart heating system using both renewable and traditional heating sources. The Vaillant aroTHERM hybrid management system switches between renewable and traditional heat sources to maximise efficiency and lower running costs.

The aroTHERM hybrid system can use either a current gas, oil or LPG boiler alongside the aroTHERM air-to-water heat pump. However, for maximum savings and performance, Vaillant recommends the hybrid system includes a modern high-efficiency Vaillant boiler.

Its pre-programmed intelligence means it’s easy to control and choose the most cost-effective heating option when energy tariffs change.

The aroTHERM hybrid system comes with a 5-year parts and labour guarantee as standard when you have one installed by a Vaillant Advance Renewable Installer, so you can have peace of mind.


A hybrid heating system (dual fuel heating system) combines a traditional (gas, oil or LPG) boiler with a renewable heating system.

A hybrid heating system will switch between the heat pump and boiler based on the most efficient option at the time, saving you energy and money. It monitors the outside temperature before making the switch.

Some hybrid heating product ranges start from £8,000 upwards. It can cost up to £20,000 depending on the location of the pipework, the changes that will be required to the pipework and the radiator sizes.

The two biggest brands that offer hybrid heating systems are Daikin and Vaillant.

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