Heat pumps are widely seen as being crucial to the fight against climate change but incentivising their use is proving difficult.
They have been described as the “central technology in the global transition to secure and sustainable heating” by the International Energy Agency, with a heat pump being able to cut carbon emissions by as much as four fifths when compared to a gas boiler and by one fifth when electricity is generated using fossil fuels, the agency’s figures indicate.
Heating buildings is responsible for about four gigatonnes of CO2 emissions each year – about 10 per cent of all emissions – so heat pumps will, by 2030, have to account for about 20 per cent of indoor heating, often replacing gas boilers, if national governments want to hit their emission targets, the IEA states.
Yet, heat pump sales are falling in Europe. Sales dropped by five per cent, from 2.77 million in 2022 to 2.64 million in 2023, across 14 European countries for which the European Heat Pump Association published data.
It was a similar story in the US, where 3.62 million heat pumps were sold last year, according to Air-Conditioning, Heating and Refrigeration Institute figures covering about 90 per cent of the market, about a 17 per cent decline on 2022’s total of 4.33 million. The fall came after what MIT Technology Review described as “nearly a decade of constant growth”.
Work to do
In both Europe and the US, high-interest rates and inflation have been blamed for a slowdown in the installation of new heating systems. In the US, although heat pump sales fell, the devices secured a slightly higher market share, as gas boiler numbers declined at a quicker rate.
According to Martin Lewerth, chief executive of Aira, a Swedish company that supplies heat pumps in Germany, Italy and the UK and has plans to launch in other European countries, it is important that governments “bring clarity”.
“Policymakers need to make sure they have a level playing field where gas is not artificially low [in] price,” he said.
In the UK, gas costs around £0.075 (Dh0.35) per kilowatt-hour (kWh), whereas electricity averages about £0.28 (Dh1.32) per kWh, almost four times the price.
Nesta, a UK innovation agency formerly known as the National Endowment for Science, Technology and the Arts, states that several factors account for the difference, including that carbon taxes are applied to electricity but not to gas. Also, Nesta states that it is typically electricity bills, but not gas bills, that have to cover the cost of programmes to promote renewable energy or tackle fuel poverty.
A significant block to the roll-out of heat pumps is that they are typically more expensive to buy and install than gas boilers, often requiring radiators to be replaced and other upgrades such as improved insulation.
“There’s always a gas boiler you can throw in and that will do the job,” Prof Bob Critoph, head of the sustainable thermal energy technologies group at the University of Warwick in the UK, said.
“You can’t just throw a [heat pump] machine in and turn it on. It needs a bit more thought. You’ve got to get things right when you install your heat pump.”
An air source heat pump installation may cost the equivalent of about $10,000 to $19,000 (Dh36,729 to Dh69,785) in the UK, for example, which could be several times as much as a gas boiler.
While government grants can help reduce the cost, the outlay is likely to be greater than that needed for a like-for-like gas boiler replacement.
Once installed, however, heat pumps have a big advantage over gas boilers: they are three to five times more efficient, which cuts energy bills.
“There’s a phenomenal opportunity for European households to save large amounts on their energy consumption,” Mr Lewerth said.
His company offers long-term financing so consumers are not faced with a big upfront bill for a new heat pump.
Heat pump use varies widely between European countries, with their usage as high as 60 per cent in Norway but just one per cent in the UK.
In the UK, heat pumps have often been subject to unflattering press coverage, with major newspapers having published articles with titles such as, “Why heat pumps will never work in Britain,” and, “Six reasons not to buy a heat pump”.
“There’s a lot of misconceptions spread around, a lot of myths,” Mr Lewerth said. “We have to educate the market.”
While last year saw a dip, heat pump sales in the US are expected to accelerate as government-funded incentives, worth up to $8,000 (Dh29,383) for many households, come on stream from late this year, while the EU’s delayed Heat Pump Action Plan could ramp up sales in the 27-member bloc.
The technology
Although sometimes depicted as a solution for the future, heat pumps are not a new invention, with the first developed in the middle of the 19th century, when an Austrian minerals industry engineer, Peter von Rittinger, used the energy in water vapour to dry salty water.
Today, a domestic heat pump may be a ground-source device that uses a network of underground water pipes to absorb heat from the ground before transferring it, through a heat exchanger, to a heat pump.
The other main type, air-source heat pumps, extract heat from the outside air and (in the case of air-to-water heat pumps) transfer it to the central heating system.
Temperatures reached are typically lower than with a heating system powered by a gas boiler, so larger radiators are often needed.
Heat pumps can create cooling too, which could make them especially useful because, according to the energy agency, by 2050 there will be 2.6 billion people living in parts of the world that require heating in winter and cooling in summer.
In countries such as the UAE, where cooling is the primary need, air conditioners are likely to remain the preferred option.
However, companies such as Ariston have been promoting heat pumps in the UAE to heat water, saying that their energy consumption can be 70 or 80 per cent less than that of a boiler.
Industrial scale
Heat pumps also find application in industry, although here the temperatures required may be higher than with domestic uses.
“The paper, food and chemicals industries have the largest near‐term opportunities. About 30 per cent of their combined heating needs to be addressed by heat pumps,” the agency stated in The Future of Heat Pumps – a report published in 2022.
Food manufacturers may use heat pumps to generate hot water or to provide heating for highly energy-intensive spray dryers used to produce milk powder.
Nestle is one of the industrial companies to make significant use of heat pumps for these purposes. The company, which aims to reach net zero by 2050, has been pushing heat pump manufacturers to speed the development of devices able to produce hotter steam.
According to reports, the firm would like electricity-powered heat pumps for uses that require temperatures as high as 200°C. Many heat pumps currently used for very high-temperature applications run on oil and so generate carbon emissions.
“A lot of the power used industrially today could be replaced by heat pumps because they can deliver up to 150°C,” Prof Brian Elmegaard, who researches heat pumps at the Technical University of Denmark, said.
“The technology is being improved with respect to temperature.”
A Japanese manufacturer, Mayekawa, is reportedly developing a heat pump capable of producing temperatures as high as 200°C.
Those used in industry may extract heat from the air or the ground, although some make use of heat from rivers, the sea or even industrial compounds such as chemical plants or data centres, the engineering firm Siemens said.
As with domestic applications, the high cost of the initial investment may limit the roll-out of heat pumps, Prof Elmegaard indicated, with a 1-megawatt unit likely to cost up to €1m (Dh4m).
He predicted that heat pumps will be used ever more widely in industry in years to come.
“Governments worldwide have taken decisions about decarbonising and companies themselves have decarbonising strategies, so they will have to use something other than fossil fuels,” he said.
