The writing is on the wall for gas boilers; from 2025, they won't be allowed at all in newly-built homes. The exact date for their phase out from existing homes is yet to be confirmed, but there will come a point when buying a new gas boiler to replace an old one simply isn't an option.
That point is still quite some time away, though. So, given the typical 10 to 15-year lifespan of most gas boilers, a like-for-like replacement will still be an option for most people next time they need a new boiler.
But with the transition to net zero underway, more of us will be considering opting for a more sustainable alternative sooner rather than later. In some cases, your next boiler replacement won't even be a boiler at all.
Read on to find out more about the options that are available now, or might be developed over the next decade. We explain how they work, the pros and cons of each, and the types of home they're most suitable for.
According to the government's Heat and Buildings Strategy, it expects heat pumps to play a major role in the future of heating in the UK.
When installed in a well-insulated home, a heat pump can run extremely efficiently and use very little electricity.They can be installed in less well-insulated homes too, but you may need larger radiators and a more powerful heat pump, which could cost more to run.
The cost of buying and installing a heat pump typically ranges from £7,000 to £13,000 for an air source heat pump, and £14,000 to £19,000 for a ground source heat pump, according to the Energy Saving Trust. This is considerably more expensive than a gas boiler, but there will soon be grants available to help with the cost (see below), and they're a much more environmentally-friendly way of heating your home than traditional gas boilers.
Heat pumps work on the same principle as fridges. They draw heat from the ground or air and use a compressor to boost it to a higher temperature.
This heat is transferred by an electrical pump to your radiators, or other heat emitters (underfloor heating, for example), to warm your home.
The two main types are ground source heat pumps, which take their heat from the ground, and air source heat pumps which (surprise surprise) take the heat from the air.
Air source heat pumps tend to be cheaper and less disruptive to install. On the other hand, ground source heat pumps tend to be more efficient over the year, as the ground temperature is more consistent.
If you're considering a heat pump, you should have a MCS-certified (Microgeneration Certification Scheme) installercarry out an assessment on your home before committing to anything. But, as a rule of thumb, a heat pump is more likely to be suitable if:
The high upfront costs may put many people off installing heat pumps, especially in a home with an existing heating system that works perfectly well.
However, a new government grant, dubbed the Boiler Upgrade Scheme, means homes in England and Wales can receive a voucher worth up to £5,000 towards the cost of an air source heat pump, or £6,000 for a ground source heat pump.
This would reduce the cost of a £10,000 air source heat pump installation to £5,000, for example. Your MCS-certified installer must apply for a voucher for the grant on your behalf.
The scheme is expected to launch later this year and has a budget of £450m over three years. This is only enough for around 90,000 homes in total - so it's likely to run out quickly.
This grant is aimed at well insulated homes: you will need a valid energy performance certificate (EPC) with no recommendations for loft or cavity wall insulation.
The price of heat pumps is expected to fall over the coming years, but if your boiler needs replacing, these grants could make a heat pump a more affordable, and sustainable, choice right now.
An electric boiler is a similar size (or sometimes a tad smaller) to a gas boiler, and is likely to have comparable costs for buying and installing the boiler itself (a new combi-boiler installation will typically cost around £2,500).
If you're looking to reduce your carbon footprint sooner rather than later, and a heat pump isn't currently viable, an electric boiler could be a more environmentally-friendly option than a traditional gas boiler.
Electric boilers work by passing electric current through a heating element to heat your water, rather than burning gas. They essentially operate like a big kettle (though they don't boil the water!)
As with gas boilers, you can choose between heat-only or system boilers (that require water tanks to store hot water), or combi boilers (that heat your hot water on-demand).
However, the maximum power output of electric boilers is typically lower than gas boilers, and your home may require expensive electrical upgrades to cope with the increased demand an electrical boiler will make on your electricity supply. These factors mean they won't be suitable for every home.
Before considering a switch, get a qualified engineer who works with electric boilers to carry out an assessment of your home.
You should always seek the advice of a trusted local engineer when choosing the best heating system for your home, but in general an electric boiler is more likely to be a option to consider if:
While all homes will eventually transition to low carbon heating systems, for many the alternatives are currently impractical, prohibitively expensive, or still at too-early stages of development.
But sticking with a gas or oil boiler next time round doesn't mean you can't improve your home's carbon footprint - and potentially save money in the process, if an old, inefficient boiler is pushing up your heating bills higher than they need to be.
Current Boiler Plus regulation means all gas boilers sold in England are at least A-rated for efficiency (which means they're at least 92% efficient).
While this rule doesn't apply to Wales, Scotland or Ireland you should still go for an A-rated boiler - keeping your heating efficient and bills as low as possible.
Having said this, all modern boilers are basically as efficient as each other, so your main priority should be choosing the right size of boiler for your home.
Too small (in terms of power output), and it won't heat your home well enough; too big, and you'll be using far more energy than you need to be.
There's an old saying: if it ain't broke, don't fix it. But even if an old boiler is still plodding along, that doesn't mean it's not worth replacing it.
If you haven't had a new boiler since 2005, or if the flue on your boiler isn't made of plastic, then there is a strong possibility it's an inefficient 'non-condensing' boiler.
All modern boilers are 'condensing', which means they recycle some of the heat that a non-condensing boiler would waste to heat water returning from your central heating system.
A condensing boiler is typically 25% more energy-efficient than an old non-condensing model, and so will mean lower heating bills - and lower carbon emissions to boot.
In fact, switching from an old boiler to a new A-rated condensing boiler with a programmer, thermostat and thermostatic radiator valves could save you anywhere from £50 to £365 a year on your heating bill (Energy Savings Trust, November 2021).
Hydrogen boilers have been getting a lot of attention recently, despite not actually being available to buy yet.
The government has yet to decide how big a role hydrogen will play in the future of heating in the UK (it's due to make its decision in 2026), but it's anticipated that so-called 'hydrogen-ready boilers' may start appearing on the market in a few years. Hydrogen-ready boilers can cope with being powered by either traditional methane gas or hydrogen, so will be good to go as and when hydrogen becomes available as a fuel .
While cost is still a relatively unknown quantity, if there is significant demand for hydrogen boilers, it's expected that purchase and installation costs will be on a par with gas boilers.
Hydrogen boilers will work in almost exactly the same way as traditional gas boilers; they'll just burn hydrogen instead of natural gas. Unlike natural gas, burning hydrogen generates no carbon emissions - though the production of the hydrogen itself isn't always carbon-free, as we explain in the cons of hydrogen boilers, below.
Hydrogen-ready boilers can run on natural gas until a switch over to hydrogen happens, at which point an engineer would come and carry out a small service to switch the boiler over to run on 100% hydrogen.
Alongside heat pumps, the government's Heat and Buildings Strategy expects that heat networks will play a significant role in heating UK homes in the future, especially in certain areas.
A heat network consists of a centralised, large-scale heating system that supplies heating to multiple homes.
Heat networks that supply heating to just one building (such a block of flats) are known as communal heat networks, while ones that supply to multiple buildings are known as district heat networks.
Currently 3% of the UK's heat supply comes from heat networks, but the government plans to increase this to around 20% by 2050.
While most existing heat networks run on gas, they are compatible with a range of heating systems (large ground-source heat pumps or hydrogen boilers that are installed nearby and are big enough to power several buildings, for example) and so can easily be converted to low-carbon energy in the future.
Connecting more homes to heat networks also helps heat homes more efficiently, as a single large heating system can have economies of scale compared with every home having an individual heating system.
Heat networks also have the space for water tanks and other storage solutions to be placed near the heat source, allowing them to store thermal energy. This could reduce demand on the grid during peak times, and reduce the overall cost of heating.
An obvious limitation is that you need to live in a location served by a heat network in order to get your heating in this way, and at present they're not all that common.
They're also not as tightly regulated as other energy suppliers, which could result in consumer issues, such as being locked into long contracts. While cheap energy deals are hard to come by at the moment, those on heat networks could have difficulty switching to an alternative provider if better deals appear in the future.
These issues will need to be addressed if heat networks are to become a mainstream form of heating.
The government plans to identify areas that can be connected to a low carbon heat network over the coming years, with a view to starting transitions to heat networks in the 2030s and beyond.