Heat pumps in buildings are in focus as the EU slashes emissions and boosts clean energy.

At the foot of the mountains of western Italy between the cities of Turin and Cuneo, Europe recently took a step forward in a campaign to provide homes with clean energy as part of the fight against climate change.

In the municipality of Verzuolo, a project called HAPPENING used EU funding to install heat pumps for a 10-unit apartment building in the run-up to this past winter. The pumps heated the apartments using solar power harnessed from rooftop panels.

Pumps push

"Most of the energy used for heating was produced by photovoltaics and we have good feedback from the users," says Lorenzo Civalleri, an engineer at Italian thermal energy company Tecnozenith, which helped to set up the system.

Buildings are a significant contributor to global warming because of their energy consumption for heating and cooling. In Europe, they account for 40% of energy demand and 36% of emissions of CO2, the main greenhouse gas.

About half of all energy consumed in the EU is for heating and cooling and more than 70% still comes from fossil fuels, primarily natural gas, according to Eurostat. In the residential sector, about four-fifths of energy consumption is to heat spaces and water.

Consequently, buildings are a significant part of new European legislation underpinning an EU push to reduce greenhouse gas emissions by at least 55% in 2030 compared with 1990 levels and to become climate neutral by 2050.

And here’s where European research and development come into play.

"Decarbonisation of existing buildings will have a key role to play in reaching the climate-protection goals that we have in Europe," says Irantzu Urkola, coordinator of HAPPENING. 

One European priority is accelerating the installation of heat pumps, which are an alternative to boilers.

With almost 17 million installed across Europe at the end of 2021, heat pumps not only are more efficient than boilers but also allow greater use of renewable energy including solar.

10 million more

Since Russia’s invasion of Ukraine in February 2022, the EU has front-loaded plans for expanding renewables and enhancing energy efficiency to accelerate a shift away from Russian fossil fuels.

'Decarbonisation of existing buildings will have a key role to play.' Irantzu Urkola, HAPPENING


As part of this 'RePowerEU' strategy, Europe aims to double the rate of deployment of heat pumps in buildings and install an extra 10 million by 2027.

That would help the EU achieve one of its big new headline targets in the climate fight: roughly doubling the share of renewables in overall energy consumption to at least 42.5% in 2030.

HAPPENING, which began in October 2020 and runs through September 2024, has focused on installing heat pumps in homes and working with their occupants to highlight the benefits including convenience and reliability.

Civalleri of Tecnozenith regards the Verzuolo demonstration, which covered 10 two-room apartments in total, as a success.

"The heating season is finished and there were no complaints – that’s good news for us," he says. "We checked the system regularly and fixed some small issues, but we’re quite happy with the functioning of the system in the first season."

Next stops: Austria and Spain

HAPPENING is now gearing up for heat-pump demonstrations in the town of Liezen in central Austria and in the municipality of Pasaia in northern Spain.

Heat pumps use electricity to warm a space or to produce hot water. The devices extract heat from the surrounding air, ground or water and 'pump' it indoors.

When solar panels are part of the system, the electricity consumed by heat pumps is renewable because it comes from the sun. In transferring the heat, the pumps avoid the need to generate it in the way that conventional technologies such as boilers do, making the system more efficient.

In Verzuolo, first the system heats the water to 20-30 °C and stores it in a central tank before distribution around the building. In combination with rooftop solar power, the water can be heated when the sun is shining and then stored in the central tank until needed, maximising the use of renewables in the system.

"Distributing water at this low temperature, as opposed to hotter water, means a dramatic reduction in heat losses," says Urkola, who works at Spain-based research and technological development centre Tecnalia.

Each apartment has its own individual heat-pump system, allowing the household to control its temperature.

The HAPPENING team will use data from the Verzuolo, Liezen and Pasaia sites to help develop guidelines for installers and consumers. In general, the project participants say a wider uptake of heat pumps is needed through more public awareness of them.

"Local authorities will need to promote these kinds of solutions for good energy renovations of buildings, using consolidated technology that is easy to install and implement," says Civalleri.

Awareness and training

Boosting awareness of heat-pump technology was an aim of the EU-funded TRI-HP project, which ended in February 2023 after four years.

As part of the initiative, the team addressed the barriers to more widespread use of heat pumps.

'There is a need for more training.' Daniel Carbonell, TRI-HP


Workshops with engineers, plumbers, architects and others responsible for installing heating systems highlighted a need for more education about heat pumps and their potential as well as improved training on how to put them in place.

In some cases, workshop participants cited higher upfront costs as a barrier. 

TRI-HP sought to develop a heat-pump system that would offer the best of the currently available technologies at a lower cost, according to Daniel Carbonell, the project coordinator.

TRI-HP, which brought together research institutes and industry partners from seven European countries, worked on two types.

One is a dual-sourcing system, which uses heat from a bore hole and from the air. Alternating between the two sources at different times of the day means the bore hole doesn’t need to be so deep, keeping investment costs down.

"It’s usually air or ground, but this technology uses both," says Carbonell, who is team leader for thermal systems and modelling at Switzerland’s SPF Institute for Solar Technology. "This is a significant cost reduction."

The second system uses the sun’s heat through so-called solar thermal collectors, passing it into water to be used as a source for the pump.

Even with technological advances like those under HAPPENING and TRI-HP, faster installation of heat pumps across Europe will depend on greater public awareness of the potential savings and more training of heating engineers.

Many installers are used to fitting gas and oil boilers that bring in easy profits. They’ll need to be convinced that it is worth learning new techniques. 

"There is a need for more training," says Carbonell. "And removing mental barriers is important too."