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Hydrogen Boiler Guide


As global temperatures increase, the world’s focus is steadily shifting towards lowering the emission of greenhouse gases. This is why heating our homes using natural gas is not a feasible idea. Boiler manufacturers understand the need to keep our homes warm and, at the same time, reverse the effects of carbon emissions. This is why the idea of hydrogen boilers is quickly becoming a reality, with boiler manufacturers like Baxi and Worcester Bosch already having working prototypes.

What is a Hydrogen Boiler?

For the average eye, the hydrogen boiler will not look very different from your current boiler. For the most part, it will also work the same way as your existing boiler.

The difference will be that the boiler will heat your home using natural gas and pure hydrogen too. Hydrogen boilers will be installed the same way as gas boilers and be connected to the gas network. Nothing much will change. Most of the internal components of the boiler will remain the same. Only a handful of the parts like the flame detector and burner could change to accommodate the use of hydrogen.

What About hydrogen fuel cell boilers?

A hydrogen fuel cell breaks down the hydrogen into different parts to generate electricity. The process emits heat as one of the byproducts. This heat can be used to heat your home or heat water.

Hydrogen fuel cell technology already exists, and there are several options that homeowners can consider when having a hydrogen fuel cell boiler installer. Viessmann is one of the brands to have a working hydrogen fuel cell boiler in their Vitovalor boiler. This technology can help lower your energy bills but is considerably more expensive than a gas boiler.

Why is it Important to Have an Alternative to Gas Boilers?

Fossil fuels are not renewable resources. That means, with the increased use, the resource is depleting and will possibly increase in price as it becomes limited. There’s also the concern that using natural gases like methane produces greenhouse gases like carbon which is released into the atmosphere, contributing to the global warming effect.

The UK government is working to reduce carbon emissions. This has been through creating laws like the law committing to reduce carbon emissions at net-zero by 2050.

Considering that heating contributes to a third of the UK’s total carbon emission, it’s inevitable that finding an alternative, renewable and carbon-free fuel will be at the top of the priority list to reduce carbon footprint.

Residential boilers have already been subjected to substantial legislation. There’s a ban on non-condensing boilers that requires all boilers to be at least 90% efficient. Considering that 8/10 homes in the UK use gas boilers and the government is working towards a complete ban on gas boilers in all newly built properties by 2025, finding an alternative to gas boilers is critical.

There are other alternatives on the table like solar or using heat pumps. But these are not considered achievable because of the substantial financial commitment. Hydrogen boilers are the most viable solution because they can leverage the existing infrastructure and engineers, and once the uptake of the boilers is stable, the price will be competitive.

How Does a Hydrogen Boiler Work?

It’s important to note that there are hydrogen boilers, and there are hydrogen-ready boilers. The two are relatively different technologies. For clarity, the process below describes how a hydrogen boiler works:

  • Oxygen and hydrogen enter the boiler

The first step of the process is oxygen and hydrogen entering the main boiler unit. The hydrogen will come from the main gas supply, and the oxygen will come from the air. The boiler will have a gas inlet valve that controls how much of each type of air can enter the boiler. It’s critical for the amount of the gases to be controlled because it will determine the size of the flame.

  • The gasses mix and burn

Once in the main boiler, the two gases mix and are ignited in the catalytic burner. Because hydrogen is more flammable than natural gas, the burners in the boiler are designed to handle the flames if there is too much natural gas flowing through into the boiler. The boiler also has a flame detection component required because hydrogen flames are invisible.  

  • The hot gases enter the heat exchanger

After the combustion of the gases, the hot flue gasses enter the heat exchanger, which is made up of a series of pipes surrounded by water. The hot gases travel through the pipes while passing the heat to the surrounding water. The hot water can then be used to heat the system or supply hot water to the taps.  

  • By-products exit the system

Water is the only byproduct of burning hydrogen and oxygen. The boiler is a condensate that is required for the water to leave the system. The hot flue gases can exit the system through the flue system. Once the gases leave the chambers, the hydrogen boiler continues to pull in more hydrogen and oxygen, and the process is repeated.

Are Hydrogen Boilers Safe?

There is a lot of hesitation in adopting hydrogen boilers because of the flammable nature of hydrogen. However, considering the government’s mass adoption of hydrogen in the future, you can rest assured health and safety are a top priority.

Hydrogen boilers will undergo stringent testing in simulated settings before being approved for residential and commercial use.

Manufacturers are also keen on producing safe boilers by involving the brightest minds from the most prominent universities in research and testing to ensure the complete safety of the boiler.

So far, boiler brands like Worcester Bosch, Baxi, Ideal, and Valent are required to supply two of their natural gas boilers for a simulated test that will involve the boilers running for 24 hours per day, 365 per day for 15 – 18 years.

According to the test details, one boiler will run on natural gas while the other will have a hydrogen blend pumped through it. Both boilers will be closely inspected and analysed at the end of the testing. Hypothetically, there shouldn’t be any visible difference between the two boilers. Until the boilers are deemed safe, the boilers cannot be used in homes.

All boilers using a hydrogen blend will have to meet all the rigorous gas and safety regulations of 1996. Therefore, you shouldn’t have any worries about the safety of hydrogen boilers. Once they come out of the experiment, they won’t be any different from your current boiler.

Where Do You Store Hydrogen for House Boilers?

Once hydrogen boilers become available, most homeowners are concerned with having a hydrogen tank in their homes. But this won’t have to be the case. The hydrogen will be instead added to the UK’s gas supply and will be automatically added to your boiler for the burning process. It will be a quick and easy process that won’t require much change in the current infrastructure, saving money for both homeowners and the government.

Advantages of a Hydrogen Boiler

There’s no question that hydrogen holds the solution for many of the renewable energy sources in the world currently. The hydrogen boiler will have an answer to one of the UK’s biggest carbon emission problems. Some of the other benefits that a hydrogen boiler will have include:

Use of familiar heating systems

Converting from a gas to a hydrogen boiler won’t be costly because the boiler will use most of the heating systems currently in place, with the added benefit of reducing carbon emissions. The alternatives in the market require unfamiliar technology that is also costly.

More environmentally friendly than natural gas

When boilers use natural gas for heating, they produce carbon dioxide and carbon monoxide gases, damaging the planet and the atmosphere. With hydrogen as an alternative, bi-products will include water and heat with no carbon, which is critical in restoring balance in the planet. Even if the boiler uses a blend of hydrogen and natural gas, the drop in carbon emission would still be significant.

Highly fuel-efficient

1kg of hydrogen contains the same amount of power as 2.8kgs of gasoline. That makes make hydrogen extremely energy efficient because you only need about half of it to produce the same amount of energy you have been producing using natural gas.

Dis-advantages of a Hydrogen Boiler

Unfortunately, there are disadvantages to using hydrogen boilers. Before opting for hydrogen boilers as an alternative, the government and manufacturers have carefully considered these downsides. Some of them include:

Hydrogen production is not cheap

Currently, there are two methods of hydrogen production: electrolysis or steam methane reforming (SMR).

The electrolysis method works by splitting water molecules into two separate hydrogen molecules using a high voltage current. In most setups, the electricity used in electrolysis is generated from renewable energy sources.

The SMR method involves reacting steam with methane. However, carbon is a byproduct of the reaction.

Both hydrogen production methods are expensive and are not cost-effective for the mass market, which requires megatons of hydrogen for nationwide supply.

Hydrogen is flammable

One of the reasons why hydrogen is an excellent alternative to natural gas is also one of its downsides. Hydrogen is more flammable than natural gas and has a high energy reserve. Also, hydrogen doesn’t have a smell, and its flame isn’t visible. Hydrogen boilers will have detectors which will be an essential part of the safe use of hydrogen boilers.

Storing hydrogen isn’t easy

Hydrogen is lighter than natural gas, making it harder to store or transport. The gas needs to be turned into a liquid and stored at low temperatures to achieve adequate conditions.

How Much Does a Hydrogen Boiler Cost?

The hydrogen boiler technology will take some time before it is ready for uptake by residential homes. It is still too early to tell how much a hydrogen boiler will cost, especially considering that there is still so much uncertainty regarding the technology.

But, the idea is that the hydrogen won’t cost much more than a regular boiler. Initially, it is expected that running on hydrogen could cost more than natural gas because of the cost of producing and transporting hydrogen. Once fully embraced, the cost of using hydrogen could lower as technology improves and more economical ways of producing hydrogen are introduced.

How Soon Can You Buy a Hydrogen Boiler?

It’s not yet possible to purchase a hydrogen-ready boiler. The boiler is still at the development and testing stages. Leading manufacturers like Worcester Bosch and Viessmann are at the advanced stages of developing their prototypes and have made significant progress over the past few years.

It’s probable the earliest possible time a hydrogen-ready boiler will be rolled is from 2025 and beyond. This will align the rollout of the new boiler with the proposed gas boiler ban on newly built properties.

There are various projects the government is working on together with the heating industry to research and test hydrogen as heating fuel. These projects are at advanced stages and include:


The HyDeploy project is running at Keele University in Staffordshire. The project is testing the viability of using a 20:80 hydrogen and natural gas blend in the national grid. Using this blend, there will be no changes to most of the infrastructure or the gas boiler, or the installation process. The mixture will be gradually phased out to hydrogen by 2025.

This project is under review by the Health and Safety Executive and could start public trials very soon.


The Hy4Heat is researching and testing the feasibility of a 100% hydrogen network. The project is reported to have plenty of positive results indicating that appliances using a hydrogen network would be similar to those using natural gas. One of the main focuses of this project is safety. Using hydrogen can be unsafe without proper safety features in place.

The installer will need additional training to work safely with hydrogen. There are hydrogen vehicles on the road so far, and a 50% hydrogen blend has been used in the gas grid in the past. According to this project, modern boilers will only require minor modifications to work with 100% hydrogen.

Hydrogen supply programme

The hydrogen supply programme is a global project being conducted by several countries trying to find an efficient and cost-effective method to produce low-carbon hydrogen. The UK government has already invested £20m in the Hydrogen Supply Programme with the aim of investigating how a viable hydrogen network would be.

With the various projects at various advanced stages, once hydrogen blends are approved, the transition to phase out natural gas will be quick and effortless.

How Can You Make Your Home More Energy Efficient And Protect the Planet Today?

The main idea behind introducing hydrogen boilers is to reducing energy consumption and the emission of carbon into the atmosphere. Although there is still sometime before hydrogen boilers become a reality, there is plenty you can do for the planet and your home right now:

  • Insulate your home – Insulating your roof and walls can make a huge difference in your home’s heating requirements. The house will hold the heat longer, reducing your energy bills and dependence on the boiler for heat.
  • Install energy-efficient boilers – If your boiler is more than 15 years old, it’s a shell of what it once was. Investing in a modern boiler with high efficiency will significantly reduce your energy bill while keeping the home comfortable.
  • Draught-proof – Most of the heat in your home escapes through leaky windows and doors. These are the leading cause of energy loss in the UK. Draught-proofing can enhance your home’s ability to retain heat and reduce the hours you should run the boiler for heat.
  • Use hot water conservatively – You can make some adjustments to how your household uses water to conserve hot water and energy. Showering simultaneously instead of heating water at different times during the day is a clever way of enjoying a hot shower while reducing your energy costs. You should also ensure you don’t leave any faucets running.
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