Eco-Friendly Boilers and Best Alternatives UK

Last updated: May 30, 2024

Thanks to increased awareness of environmental sustainability, more people are looking to live greener lifestyles. Read on to learn more about eco-friendly boilers and how they can help you reduce your carbon footprint and energy bills.

According to the National Audit Office, heating the UK’s 28 million homes accounts for 18% of all UK emissions. Natural gas used for cooking and heating is the main source of these emissions.

The UK Government has set targets to achieve net-zero carbon emissions by 2050. Reducing emissions from heating homes is a key component in helping the government achieve its goal.

Going green with your boiler can ensure you get the heating you need while causing less harm to the environment.

Apart from reducing your carbon footprint, eco-friendly boilers can also save you money on your heating bills.

This guide explores everything you need to know about eco-friendly boilers in the UK, including how you can tell a boiler is eco-friendly, the types available in the market, their benefits, and other eco-friendly measures you can take to reduce your household emissions.

Eco-friendly boilers from Worcester Bosch
Image by Worcester Bosch

Quick Takeaways:

  • Eco-friendly boilers are an energy-efficient type of heat source that produces little or no carbon emissions.
  • The ErP rating can help you determine how eco-friendly a boiler is by showing you its energy efficiency.
  • Types of eco-friendly boilers include condensing boilers, biomass boilers, hydrogen boilers, and electric boilers.
  • Replacing your old boiler with a new, A-rated condensing boiler can make your home more eco-friendly and cheaper to heat.
  • Other measures you can take to make your home more eco-friendly include insulation, draught proofing, installing smart controls, and load and weather compensators.

Are you wondering which boiler manufacturers performed best? Check out our best boiler brands guide for the full rundown and if you are trying to determine who the best boiler installation company is, check out our Warmzilla and Boxt reviews.

Check out our video on how to vet boiler brands/models in the UK:

What are Eco-Friendly Boilers? (Do they exist)

An eco-friendly boiler is an energy-efficient type of heat source that produces little or no carbon emissions.

Eco-friendly boilers offer high energy efficiency levels from both the device itself and the heat loss mechanisms. Once installed, they can help reduce household energy bills, allowing you to recoup some of the initial investment in the new boiler.

There are many highly efficient boilers on the market, however, they will often still produce greenhouse gases during both the manufacturing process of the boiler itself and the operation process when running the boiler.

Eco boilers are different from energy-efficient boilers as they are powered via renewable energy sources that can either be replenished quickly or will not run out at all.

Best boilers

Which Are The Most Eco-Friendly Boilers?

The most eco-friendly boilers on the market are modern, A-rated condensing boilers.

Eco-friendly boilers have high efficiencies and convert more of the fuel they burn into energy.

For example, a boiler with 92% efficiency will use 92% of the energy to generate heat, while 8% will be wasted. This wasted energy or heat is mostly emitted via exhaust fumes.

Although they still release carbon dioxide, modern A rated boilers produce less emissions than old combi boilers that are G-rated and could be as low as 60% or 70% efficient.

Eco-friendly boilers are more efficient because they’re condensing. Condensing boilers recover more heat from the exhaust flue gas and use it to heat the central heating water.

Inefficient boilers waste more fuel and demand more fuel to achieve the same amount of hot water as modern efficient models. Since they convert less fuel to energy, they also emit more carbon.

How Can You Tell If A Boiler Is Eco-Friendly? 

All household appliances, including boilers, have an Energy Related Products Directive (ErP) rating. This directive aims at improving the efficiency and performance of appliances, including heating and hot water products.

The ErP makes it easier for end users to determine the level of energy efficiency inherent in their appliances. It can help you determine how eco-friendly a boiler is by showing you its energy efficiency.

The information is on the product packaging and is also usually displayed on a sticker or label on the appliance itself.

Boiler erp label

The ErP labels must show how energy-efficient a product is using a clear, easy-to-understand color-coded letter scale from G (the lowest rating) to A (the highest rating).

The Boiler Plus Standards introduced by the UK government in 2018 require all new boilers to have a minimum ErP rating of 92%.

You can read more about boiler efficiency here. 

Types of Eco-friendly Boilers 

There are various types of eco-friendly boilers currently available on the market. You can consider them when installing a new boiler or replacing an old one whether you’re a property developer, homeowner, or landlord. They include:

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Condensing Gas Boilers

After 2005, new “Boiler Plus” legislation was passed in parliament, requiring all new gas boilers to have condensing technology.

This basically means they have a new design that enables them to recycle the hot flue gases, drastically increasing their efficiency.

Therefore, if your boiler is over 10-15 years old, it’s likely to be a non-condensing model. These models had efficiency ratings between 60% and 80%, while today’s condensing varieties have efficiency ratings of 90+.

In simple monetary terms, that means that for every £1 spent, 90p is converted directly into heat, so the savings can be substantial.

A condensing boiler can also significantly reduce your carbon footprint.

Trading in your old boiler for a modern condensing boiler you could save as much as 1,220 kg of CO2 each year.

Gas Safe Engineer Patrick Garner

Have you heard about the gas boiler ban and are wondering what the alternatives to gas boilers are? Read our complete guide to replacing your gas boiler with a heat pump.

Hydrogen Ready Boilers 

These are boilers that burn hydrogen gas as fuel, as opposed to the usual natural gas.

The benefit is that when hydrogen is burned, it produces zero carbon and only water vapour, which is extremely eco-friendly as it’s a carbon-zero heating method.

100% hydrogen boilers are not yet available for purchase. However, boiler manufacturers are currently working on prototypes, and it’s assumed they’ll become available over the next decade.

Currently, only hydrogen-ready boilers are available. These boilers are able to accept a mix of hydrogen and natural gas, which can help households prepare for the transition to hydrogen fuel via the national grid.

The government proposes that hydrogen-ready boilers be technically prepared to be converted, normally within 2 hours, into safe boilers that can use 100% hydrogen as a fuel. They should also maintain the minimum energy efficiency performance standard.

This will make adoption quicker, cheaper, and easier to roll out nationwide.

Did you know that your boiler’s efficiency can impact the amount of energy it uses and, ultimately, your heating bill costs? Check out our guide to the best condensing boilers to learn more.

You may also find our review of the best eco-friendly boilers of interest.

Eco Biomass Boilers

Biomass boilers are fuelled by burning renewable organic materials such as wood chips or pellets.

Wood fuel chips or pellets are carbon neutral. During the life cycle of growing the wood for the chips or pellets, the trees absorb an equal amount of carbon as the process of burning the wood as fuel.

Modern biomass boilers are highly efficient for heating water and providing heating. According to the Energy Savings Trust, a wood-fuelled biomass boiler can save up to £1,100 a year on fuel costs.

Biomass boilers use an affordable heating fuel and are a lower-carbon option than boilers that use fossil fuels.

Replacing a fossil fuel system with a biomass boiler can save up to 12 tonnes of carbon dioxide emissions a year.

However, biomass boilers can be costly. An automatically fed pellet boiler for an average home can cost around £18,000, including installation.

Electric Boilers

Electric boilers heat water using electricity and circulate that warm water through radiators, or underfloor heating pipes.

They’re considered 100% green since the energy they use is converted directly to heat and produces zero emissions. 

Most electric combi boilers have 100% efficiency ratings. This means they convert all the energy they use directly to heat, and unlike gas boilers, they don’t lose any of the heat through exhaust fumes.

Although electric boilers don’t produce emissions, the electricity they use isn’t always generated cleanly unless you use a renewable energy source.

Electric boilers can be fuelled purely by renewable energy sources, such as solar or wind energy, either at the property or by selecting a green energy provider or tariff.

Electric boilers operate similarly to a gas combi boiler. Therefore, they can be a fairly hassle-free switching solution for households due to similar space requirements and facilities already in situ.

Several manufacturers produce electric-powered boilers on the market. These include the Electric Heating Company, Heatrae Sadia, or Elnur, offering electric boilers averaging around £1,500 plus installation.

What are the Benefits of an Eco-Friendly Boiler?

There are a number of benefits that a household can receive from an eco-friendly boiler. These include:

  • Reduced carbon emissions – As already highlighted, the pressure to reduce each household’s carbon footprint is growing. Therefore, the first benefit of opting for an eco-friendly boiler is knowing that you are doing your bit for the environment.
  • Increased safety – Eliminating the use of gas within a property removes the risk of carbon monoxide poisoning from traditional boilers.
  • Maximum fuel savings – Eco-friendly boilers generally offer an energy-saving rate of at least 90%. They use less fuel to provide hot water and central heating and subsequently save the household money by decreasing their energy bills.
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Can Replacing An Old Boiler Help Increase Eco-Friendliness?

Yes. Replacing an old, inefficient boiler can significantly reduce your carbon footprint while saving you money on energy bills.

Data from the Energy Savings Trust shows that replacing an old gas boiler with a new A-rated condensing boiler can save up to £475 annually, depending on your home’s size and thermal performance.

An old boiler will no longer operate at its optimum efficiency, so it’s worth upgrading to a new model.

Signs that can show you it’s time to replace your boiler include:

Frequent Breakdowns

A new boiler will make the most financial sense if you find yourself calling an engineer more than once a year (on top of your regular servicing) to fix new or recurring problems.

Before too long the amount you spend to fix frequent breakdowns will amount to the cost of buying a new boiler.

Higher Energy Bills

Old and inefficient boilers will waste a considerable amount of energy when heating your home, which is bad for your pockets and the planet.

If you’ve noticed your utility bills creeping up in spite of no major changes to your household’s energy usage, it’s likely that it’s time for a new boiler.

Banging or Gurgling Noises

Most of the time, the sounds and noises you’ll hear coming from your home’s central heating system are normal. They can come from pipes expanding and contracting, water moving through the system, or the boiler firing up.

Noises can also develop due to sludge blockage or buildup, but a power flush can quickly fix this.

However, if you hear any new, excessively loud, or persistent sounds like kettling, banging, gurgling, or clunking, it can be a sign of a more serious problem, especially if it’s accompanied by vibrations.

You Can’t Find A Needed Part

Older boilers are sometimes impossible to repair because the parts needed to do the job are no longer in production.

If you can’t obtain the components, you can only replace your boiler with a newer model.

The parts may also be too expensive for the repair to be worthwhile. Therefore, it may be better to invest in a new boiler that is more energy-efficient and reliable than the current system and less likely to need repairing in the near future.

Further Eco-Friendly Measures

In some cases, you may not be ready to commit to a new eco-friendly boiler because your current model still works efficiently or due to the costs of a new boiler installation.

However, various measures can help decrease your household’s carbon emissions. These include:

Installing Insulation or Draught-Proofing Measures

There is an array of measures you can install to reduce your carbon emissions and energy bills. These include:

  • Solid Wall Insulation – Insulating your solid walls can considerably cut your heating costs, and make your home more comfortable. Data from the Energy Savings Trust shows a solid wall insulation can save up to £550 annually on energy bills and up to 1500 kg annually on carbon emissions.
  • Roof and Loft Insulation – Insulating your loft, attic or flat roof is an effective way to reduce heat loss, heating bills, and carbon emissions. Insulating an uninsulated loft or roof with 270mm of insulation can save up to £370 annually on energy bills and up to 1000kg of carbon emissions annually.
  • Floor Insulation – Insulating your ground floor is another excellent way to keep your property warm, and lower your energy bills and emissions. Data shows floor insulation can save you up to £110 on energy bills and up to 310kg of carbon emissions annually.
  • Draught-proofing – Draught-proofing is an effective and cheap way to keep your home warm and energy efficient, save money on fuel bills, and lower your carbon footprint. It involves blocking up unwanted gaps that let cold air in and warm air out, helping you use less energy to heat your home.

While some of these jobs can look DIY-friendly, it’s always advisable to use professional services. This ensures you get an expert with the experience and qualifications to do a quality installation.

In addition, if someone in your household is eligible for Government schemes, you can get funding to cover the costs of installing the measures.

Have you heard about the gas boiler ban and are wondering what the alternatives to gas boilers are? Read our complete guide to replacing your gas boiler with a heat pump.

Installing a Passive Flue Gas Heat Recovery Device (PFGHRD)

A PFGHRD is a device that has been developed to capture the heat generated within the flue of the boiler. The heat is then recycled to heat up the water entering the boiler.

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Modern boilers will already have a PFGHRD fitted. However, if your model does not, it is worth investigating the options to add this device.

Installing Smart Technology

Smart thermostats, zoning tools, or monitoring apps can help minimise energy waste.

Fit the radiators with temperature control valves. These valves allow the manual operation of each radiator’s temperature.

If not already in place such valves can be fitted onto the side of each radiator. This provides an option of turning the radiators down or off in rooms that are not in constant use.

How old is your boiler? Should you consider a boiler repair or start looking at the latest boiler prices? It’s no secret that boiler efficiency deteriorates over time.

Installing Weather or Load Compensators

Weather or load compensation controllers provide additional controls in order to improve the efficiency of a heating system.

Load compensators monitor the internal temperature and adjust the boiler settings in reaction. Weather compensations provide external sensors to adjust the boiler settings for the weather.

Such technology provides the boiler with actual temperature readings rather than simply operating on a programmed timer, therefore saving energy.

What size boiler is right for your home? If you are thinking about a combi boiler, it is largely determined by the number of radiators in your home.

Check out our complete guide to new boiler installation here if you are wondering about the best type of boiler for your home. 

How much may a new boiler cost? Are you considering converting from a conventional to a combi boiler? Use our boiler installation cost calculator to get an estimation.

Are There Eco-Friendly Alternatives To Gas Boilers?

Yes. Some eco-friendly alternatives to gas boilers in the UK include:

Heat Pumps

Heat pumps work like a reverse fridge and can use an air or ground source.

Air-source heat pumps extract air from outside and compress it to reach high temperatures. They can power your home’s hot water and heating systems, while ground-source heat pumps absorb warmth from the ground.

These systems don’t rely on fossil fuels, making them better for the environment than gas or oil boilers. However, heat pumps can have high upfront costs compared to gas boilers.

Depending on the type of heat pump, purchase and installation costs can range from around £14,000 to £34,000.

To encourage the switch to heat pumps, the Boiler Upgrade Scheme, a government-funded initiative for renewable heating systems, offers up to £7,500 to assist with the cost and installation of heat pumps.

With the government likely to phase out fossil fuel heating systems, now might be the best time to switch to a low-carbon emission heating system like a heat pump.

Infrared Panels

Infrared panels are still new to the heating scene in the UK but have a promising future. They can be fitted to ceilings or walls, providing near-instant, invisible heat to individual rooms.

Infrared panels are highly controllable and heat like the warm sun on a cold day instead of relying on convection currents to carry warm air around the room.

Depending on the installation, they can use around four times less energy than a standard electric radiator.

However, to fully replace a boiler’s functionality, you must pair infrared panels with an air-source hot water cylinder.

An infrared panel system for a three-bedroom house can cost around £2,000–£2,500, but this can increase depending on the number of rooms.

Solar Thermal Heating Panels 

Solar thermal panels use the sun’s radiation to heat water, which is then supplied to your central heating system and water outlets like taps and showers.

They differ from solar PV, which uses the sun’s rays to generate electricity. However, you can also use PV solar for heating by powering an immersion heater. 

By harnessing the free power of the sun, you are able to supplement your current heating system and reduce your carbon footprint and energy bills. 

Eco-Friendly Boilers Conclusion 

There are many benefits of installing an eco-friendly boiler, including reducing your household’s impact on the environment and reducing energy costs. Eco-friendly boilers offer high energy efficiency levels and produce little to no carbon emissions.

When looking for eco-friendly boilers, you can consider options like condensing boilers, biomass boilers, electric boilers, and hydrogen-ready boilers. Replacing your old boiler with a new, A-rated boiler can also help make your home more eco-friendly and cheaper to heat.

Should you need any further advice on which type of eco-friendly boiler would be most suitable for your property, please seek advice from a qualified heating engineer.

Sources and References

  • https://www.nao.org.uk/wp-content/uploads/2024/03/Decarbonising-home-heating-HC-581-SUMMARY.pdf
  • https://assets.publishing.service.gov.uk/media/660c52b9fb0f770011ec66da/improving-boiler-standards-and-efficiency-consultation-government-response.pdf
  • https://energysavingtrust.org.uk/advice/biomass/?_gl=11ftcbw1_upMQ.._gaMTg1OTUxNTEzOS4xNzE3MDI2NDA1_ga_GPYNXFLD7G*MTcxNzAyNjQwNC4xLjAuMTcxNzAyNjQwNC4wLjAuMA.
  • https://energysavingtrust.org.uk/advice/boilers/
  • https://energysavingtrust.org.uk/advice/solid-wall-insulation/?_gl=116jfajo_upMQ.._gaODkyMjM4NjIzLjE3MTcwMjk0MzM._ga_GPYNXFLD7G*MTcxNzAyOTQzMy4xLjAuMTcxNzAyOTQzMy4wLjAuMA..