Germany’s Vaillant has developed an air-source heat pump that uses propane (R290) as the refrigerant. It can produce between 3.5 kW and 12 kW of heat, and domestic hot water to a temperature of up to ...

Worldwide, people are increasingly turning to heat pumps to warm their home. They save money, and they're good for the environment. In Northern Europe, they've long proved their worth in colder ...

The boxy machines look and function like large air-conditioners on reverse, but Germans hope they hold the key to Europe’s push for fossil-free heating. By Melissa Eddy and Patrick Junker Photographs ...