Eco heating: what are the options?

Gas and oil boilers cost many of us a fortune in heating bills, and that cost has soared since Putin’s invasion of Ukraine and will now increase again as a result of the war on Iran. What’s more, burning fossil fuels to heat our homes is damaging the planet. So, with home heating one of the most polluting sectors in the UK, is it time to switch to electric?

Electric heating will certainly make an enormous difference to your carbon footprint. For example, a small, terraced house with a well-insulated loft and a modern gas-fired boiler produces around 2.5 tonnes of planet-warming greenhouse gases a year. That’s equivalent to driving 10,870 miles in an average car or flying 10 round trips to and from Rome. There are different options for electric heating, but as an illustration, moving from gas to an air source heat pump could cut your home heating emissions by 80%.

You could also save around £300 a year on heating bills with an efficient heat pump and using a smart thermostat designed for heat pumps. This is because heat pumps are ultra-efficient and only use 1 unit of electricity to produce 3 or more units of heat.

Other types of electric heating may not reduce your energy bills much, and may even increase them because they aren’t as efficient as heat pumps. If you’re keen to save money, also check out our top tips for saving money on your energy bills.

Let’s take a look at the pros and cons of 6 eco heating options… 

1. Heat pumps

How do heat pumps work?

A heat pump is basically a fridge in reverse. Rather than making the inside colder and transferring the heat outside, it does the opposite. It extracts heat from the environment outside and pumps it into the house.

Roughly speaking, for every unit of electricity you use to power it, it will provide 3 units of heat. It's therefore by far the most efficient form of heating out there. In fact, a heat pump can reduce your carbon footprint from heating by 80% or more.

I got an air source heat pump 6 years ago and it’s kept our home warm, including through cold winters in the north of England. It extracts heat from the air outside, even when it’s freezing cold, and uses it to heat the water in our radiators and in our hot water tank.

The model we bought doesn’t make the water as hot as a gas-fired boiler, so to ensure our house is warm enough we’ve had to increase the size of our radiators. But new models now heat water as hot as a gas boiler will, so you won’t need to fit insulation or bigger radiators if you don’t want to. The heat pump itself is in our backyard where it hums away quietly.  

There are also other types of heat pump:  

• Ground source heat pumps extract heat from the soil. They’re more efficient and therefore cheaper to run but much more expensive to buy, and you’ll need a garden to lay the pipes.  
• Air-to-air heat pumps blow warm air into your house rather than providing hot water for radiators. These are likely to be suitable if you live in a small house or flat. They don’t provide you with hot water though.
• Hybrid heat pumps work alongside your gas boiler. These might have been useful in the past for homes that couldn’t be easily insulated and when heat pumps provided only low-temperature heating. But with new models providing higher temperature water they’re now largely obsolete, although they’re still being sold. The government doesn’t provide a grant for these either.

How much do heat pumps cost?

The average cost of fitting an air-source heat pump is around £11,000 but prices can vary considerably depending on your home and who you ask, a ground-source heat pump is much more expensive. The government provides a £7,500 grant towards the cost of fitting a air-source or ground-source heat pump. It also provides a £2,500 grant for an air to air heat pump, which are cheaper to install (with a range of £4,000 to £9,500).

Your heat pump is much cheaper to run if you use an electricity tariff which costs less outside of peak hours. Many of the energy companies now provide tariffs designed for heat pumps, for example the Cosy Octopus tariff. You can even now get a smart controller designed specifically for heat pumps, such as the Passiv Smart Thermostat, which will increase the efficiency of the system by almost 20%.

Heat pumps are a relatively new technology in the UK, unlike mainland Europe where they’re more common. Because of this, we’ve heard stories of poor installation leading to much lower efficiencies and in some cases energy bills rocketing. To get a government grant you’ll also need to use an accredited installer, but you might want to play extra safe and opt for those with great reviews, like Octopus Energy.

Pros of heat pumps

• Heat pumps are a very efficient way of providing heating, using roughly 1 unit of electricity to produce 3 or more units of heat.
• A grant is available from the government (installers can apply for the grant on your behalf).
• Heat pumps will make a massive positive impact on your carbon footprint
• You can buy smart thermostats designed specifically for heat pumps to optimise performance and lower costs, saving £300 a year or more on your energy costs.
• A number of companies now provide tariff options tailored for heat pumps to help lower bills.

Cons of heat pumps

• Heat pumps do involve some disruption to your house, for example pipework and a water tank.
• You'll need to be happy with a heat pump outside your house making some noise, although it’s only about as loud as a fridge and will be working hardest in winter when you’re less likely to be outside.
• Even though they use much less energy, they won’t always lower your bills if you are on a standard tariff because electricity is four times the price of gas.

2. Heat batteries

How do heat batteries work?

There’s been a fair bit of innovation on other types of electric heating in recent years. Relatively new on the scene are thermal heat batteries. These use electricity overnight, when it’s cheaper, to store as heat. 

There are two types: 

• A thermal heat battery that provides you with hot water only. They are smaller that a hot water cylinder if you are short of space or if you are fitting an air to air heat pump.
• A thermal heat battery that heats the water for all your home’s radiators when needed via a heat exchanger. It can also heat a hot water tank for showers etc. It’s about the size of a fridge and doesn’t have an outside unit.

How much do heat batteries cost?

A hot water only heat battery will cost around £3,000 whereas a heat battery which provides hot water and heating costs £6,000, plus installation.

Pros of heat batteries

• Heat batteries enable you to use low-cost electricity.
• They are small and don’t need you to have an outside area, so they’re more suitable for flats or small homes.
• They'll reduce your home heating carbon footprint by about half.

Cons of heat batteries

• For the heating plus hot water version you’ll need a hot water tank alongside the heat battery.
• The running costs are going to be similar to a gas boiler as long as you use the much cheaper electricity that's available overnight through the Economy 7 tariff or similar.
• There’s no government grant available for these, although the government is considering whether to provide one.

3. High heat retention storage heaters

How do high heat retention storage heaters work?

These are much better insulated than old-fashioned storage heaters, which use electricity to warm up heat bricks during the night and slowly release it during the daytime. This means they're much better at providing heat when you need it.

The switch to high heat storage heaters is straightforward, so long as you have an electric supply near to where you want to fit the radiators. They come with individual room controls and the better models match energy input to outside temperatures.

How much do high heat retention storage heaters cost?

An individual radiator costs around £800 plus fitting, so the total cost will depend on how many rooms you have as you’ll need a radiator in each. Like heat batteries, they use electricity at night time so you’ll want to ensure you’re on an Economy 7 tariff or similar.

Pros of high heat retention storage heaters

• They’re easy to install.
• They’ll reduce your home heating carbon footprint compared with your gas boiler, although not as much as a heat pump (around 50% compared with 80%).
• Their gradual release of heat makes them ideal if you're at home most of the day. 

Cons of high heat retention storage heaters

• You’ll need one in each room so they’ll probably cost you a lot more than a heat pump, especially because, unlike heat pumps, they don’t come with a government grant.
• They may cost more than a heat battery. But if you live in a small flat with only a few rooms they may be a good option.
• High heat retention storage heaters don’t heat your water.

4. Electric radiators and boilers

How do electric radiators and boilers work?

Electric boilers and radiators use electricity directly from the grid to provide you with heat when you need it. Electric boilers operate like a gas boiler in that they heat water for radiators and provide instant hot water for your taps. Electric radiators just provide heating to a single room. Many will be programmable and have smart controls.

How much do electric radiators and boilers cost?

They’re cheap to buy and fit compared with the options above (electric radiators are as little as £250 each including fitting, while electric boilers are around £3,000 including fitting). But because they use electricity at peak times, they’re a lot more expensive to run than other eco heating options.

Pros of electric radiators and boilers

• They’re cheap to purchase and install.
• They’ll make some carbon savings on your home heating (approximately 20%).

Cons of electric radiators and boilers

• They’re expensive to run.
• The carbon savings will be less than other eco heating options because peak-time electricity uses more fossil fuels.

5. Infrared heaters

How do infrared heaters work?

Infrared heaters provide warmth by heating objects themselves rather than the air. Like sitting in the sun on a winter’s day, you can still feel warm even though the air is cold around you. For example, we’ve got used to seeing these outside cafes and pubs.

One advantage of these heaters is that they’re super thin and lightweight. This means they can be located on your ceilings pointing down, printed over on your walls to look like pictures or hidden behind mirrors.

How much do infrared heaters cost?

Retailers claim they’ll be no more expensive than fitting traditional electric heaters. They’re also said to be more efficient than electric radiators, leading to lower bills.

But like electric radiators they use electricity straight from the grid when needed. This means they have higher running costs when used at peak times like early evening.

Pros of infrared heaters

• They can look great and be hidden around your home.
• They offer savings compared with conventional electric radiators, according to manufacturers.
• They’ll reduce your carbon footprint, although not as much as heat pumps, heat batteries and storage heaters.

Cons of infrared heaters

• Like conventional electric radiators, they’ll use peak-time electricity, not Economy 7, so they’ll be more expensive to run than other options (except electric radiators).
• Like electric radiators, carbon savings will be less than other eco heating options because peak-time electricity uses more fossil fuels.

6. Biomass boilers and wood-burning stoves

How do biomass boilers and wood-burning stoves work?

At first glance, they seem like a great option. Like gas-fired boilers, biomass boilers heat your radiators and hot water, but rather than burning fossil fuels they burn trees – trees that can be replanted and managed sustainably. Trees can also fuel a wood-burning stove to heat a single room. But it’s less clear cut than that (excuse the pun).

The carbon footprint of a biomass boiler or wood-burning stove depends very much on the source of the wood. In some cases, it might actually be worse for the climate than gas-fired heating systems if healthy old-growth forests are chopped down and not replaced, releasing all the carbon they previously trapped.

In urban areas, wood burning is rightfully coming under the spotlight because of its contribution to air pollution (the intensity of which will vary enormously between models of stoves and burners). In some urban areas, biomass boilers aren’t allowed.

How much do biomass boilers and stoves cost?

Biomass boilers can cost around £18,000 including installation, but rural homes that are off the gas grid can get a £5,000 grant from the government. Wood-burning stoves are around £600 each plus fitting, but obviously you’ll need one for each room.

Pros of biomass boilers and stoves

• They’re a reasonable option for rural, off-grid homes, although in most cases they’re no better than electric heating (especially heat pumps) for reducing your carbon footprint (and could be a lot worse).

Cons of biomass boilers and stoves

• They’re not suitable for urban or semi-urban areas due to air pollution issues.
• The wood chips or logs could cause more harm than good (the government has a list of suppliers, including those with sustainability standards). 

Choosing heating for your home

Opting for an air source or ground source heat pump is the best option if you have outside space and space internally for a hot water tank. If external or internal space is unavailable, better options might be an air-to-air heat pump, a heat battery (if you already have central heating with radiators) or high heat retention storage heaters.

If you don't want or can’t fit a heat pump, then a heat battery or high heat retention storage heaters aren’t a bad fallback. Their ability to deliver carbon footprint reductions will increase as the UK’s renewable energy increases.

To help save money, make use of the various energy efficiency schemes and grants available. Uswitch has a handy free tool that checks your eligibility for regional and national schemes across the UK.