House Design

Eco heating – from heat pumps to boilers and furnaces

Find out about the eco heating options that can make your home greener and reduce bills

House in snow - eco heating
(Image credit: Sam Beasley/Unsplash)

Are you wondering about eco heating options? Consciousness about our responsibilities to the planet as well as the desire to keep utility bills low can prompt a re-think of space-heating systems for our homes.

See: Eco home improvements: how to make your house greener

‘We’re in an energy transition and while 100 per cent renewable products have existed for a while, customer confidence, installer experience and the incentives necessary to drive widescale change still have some way to go,’ says Christian Engelke, technical director, Viessmann

‘Renewable and conventional heat generators can be combined with intelligent controls deciding which is the more efficient source to activate based on environmental and economic factors. For example, a back-up boiler can reduce overall carbon emissions if used in conjunction with a heat pump, particularly in minus temperatures where the desired comfort level can be achieved more efficiently with gas and combustion, than with an overworked heat pump consuming high levels of electricity.’ 

Read on to discover the eco heating choices available and how they can make your home greener and cheaper to run.


April 2021 is our Green Homes month. Throughout this month and beyond, we will be highlighting the changes you can make to your home to make them more sustainable – from big projects, such as heating and cooling, to small changes, like buying sustainable homewares.

Find more eco guides on our dedicated page.

Choose an eco boiler

Google Nest thermostat - Eco heating

(Image credit: Google Nest)

If your home is heated by a boiler, replacing an old version with a modern model can be an eco-friendly move, as well as a money saver. Boilers work by heating water that’s distributed to radiators and taps, but the latest designs do their job in a far more efficient way than before. 

In the US, you can check a boiler’s annual fuel utilization efficiency (AFUE), which should be displayed to make comparison between models easy. Old systems have an AFUE of 56 to 70%, according to Energy Saver, an office of the US Department of Energy providing energy efficiency and renewable energy information to consumers. The latest offer efficiencies of 90 to 98.5%, which can both cut fuel bills but also pollution, says Energy Saver. 

In the UK, domestic heating technology has also vastly improved. Both gas and oil fired boilers for new installations and fitted as replacements have to be high efficiency condensing designs that recover heat from waste gases and use it to preheat cold water entering the boiler. 

‘An older non-condensing boiler can fall to 50% efficient after years of use,’ explains Ian Henderson, Managing Director of Boiler Plan. ‘New high efficiency boilers with a smart thermostat, however, can achieve over 90% efficiency, resulting in huge savings over the year.’

Select between combi boilers – which provide heat for the radiators and hot water on demand – and system boilers – which are fitted to sealed heating systems but store hot water in a cylinder.

See: Solar panels – a complete guide

Upgrade the furnace

Eco heating - living room

(Image credit: Kevin Lichten)

Furnaces heat air rather than water and use a blower motor and air ducts to distribute the warm air around a home. Like investing in a new boiler, fitting a new, modern furnace can be an eco improvement worth making if your home is heated this way.

As with boilers, efficiencies have improved dramatically with the best offering an AFUE (see above) of up to 98.5%, which means nearly all the fuel becomes useful home heat. 

‘Before buying a new furnace or boiler or modifying your existing unit, first make every effort to improve the energy efficiency of your home, then have a heating contractor size your furnace,’ advises Energy Saver. ‘Energy-efficiency improvements will save money on a new furnace or boiler, because you can purchase a smaller unit. A properly sized furnace or boiler will operate most efficiently.’

You can look for the Energy Star label when you are shopping for a new furnace, which shows it has met strict energy efficiency guidelines set by the US Environmental Protection Agency. 

Energy Saver recommends a sealed combustion furnace, which save energy compared to non sealed versions. They also avoid the problem of introducing combustion gases to your home. 

Consider an air source heat pump

Air Source Heat Pump - Eco heating

(Image credit: Vaillant)

An air source heat pump could take the place of a boiler or furnace, but it works differently. It doesn’t burn fuel to create heat, but instead moves it from one place to another. Heat from the air gets absorbed into a fluid, which causes it to become a gas. The gas is then compressed, raising its temperature. The higher temperature is then transferred into the heating system.

In the US air source heat pumps have been used for many years, but until recently not in areas with long periods of sub-zero temperatures, says Energy Saver. Now, though, because of the advance of technology, they are an eco heating alternative for these regions, too.

Electricity powers the heat pump but one of these could be combined with solar photovoltaic panels and a system inverter. ‘The PV system will connect to the heat pump, and when you generate photovoltaic power, the heat pump will use that power to heat the home and the hot water,’ says Mark Wilkins, Technologies Director at Vaillant.

‘It is possible that you will need a battery storage or buffer storage system in addition to the heat pump because you rarely produce electrical power from PV when you need to generate heat. Therefore you store the electricity generated in batteries and use it when you need it or use the heat pump in the day time, heat water and store it in a buffer store for use when you need heating. You could also use the photovoltaic power in the summer with your heat pump to provide comfort cooling when it is especially hot (assuming your system is set up for cooling).’

Go for a ground source heat pump

Ground source heat pump - eco heating

(Image credit: Vaillant)

A ground source heat pump, also referred to as a geothermal heat pump, is another eco heating alternative. They use energy from the sun to heat a home via a series of buried pipes that extract that energy from the ground the sun warmed. The heat pump amplifies the energy into heat for a home.

A geothermal heat pump has two main elements: the ground array, which can be a horizontal series of pipes or two or three vertical boreholes, and the heat pump itself, which can be installed in the house or outside.

See: The world's most beautiful eco houses – from forest dwellings to city homes

‘Both ground source and air source heat pumps are highly efficient, eco-friendly heating systems, but ground source heat pumps tend to have higher efficiencies over the year,’ says Mark Wilkins. ‘This is due to the higher, more stable temperature of the source energy which is consistent throughout the year. However, both systems are highly efficient and selecting the appropriate heating system will depend upon your property and requirements.’

Sarah Warwick

Sarah is a freelance journalist and editor writing for websites, national newspapers, and magazines. She’s spent most of her journalistic career specialising in homes – long enough to see fridges become smart,
decorating fashions embrace both minimalism and maximalism, and interiors that blur the indoor/outdoor link become a must-have. She loves testing the latest home appliances, revealing the trends in
furnishings and fittings for every room, and investigating the benefits, costs and practicalities of home improvement. It's no big surprise that she likes to put what she writes about into practice, and is a serial house revamper. For, Sarah reviews coffee machines and vacuum cleaners, taking them through their paces at home to give us an honest, real life review and comparison of every model.