Heating and cooling our buildings comes with a hefty environmental footprint. In the US alone, heating and cooling systems account for 38 percent of greenhouse gas emissions of residential housing. Coming up with more sustainable ways to maintain a favorable temperature within our homes is thus key towards meeting our global climate targets. A team of scientists in Germany has recently come up with a modular retrofit system that could make our buildings more eco-friendly.

Developed by researchers at Fraunhofer Institute, the system consists of a modular facade powered by solar energy that can heat or cool rooms. Each individual unit measures 125 cm wide and 30 cm deep (49.2 x 11.8 in), and is suitable for rooms measuring up to 24m² (258 ft²). The modules are also integrated with solar panels that can generate enough power to run a mini heat pump.

For heating, the system uses fan coils to pump in heat from the outside. As for cooling, the system extracts heat from indoors and blows it outside. The facade also has a decentralized ventilation system that regulates this air exchange, allowing the room to “breathe.” The system is also connected to mainline power as a backup in case the solar panels can’t generate enough power.

What’s particularly attractive about the facade design is that it can be retrofitted directly onto older buildings, particularly those built between the 1950s and 1970s, the team says. This offers the option to bring existing offices or residential housing up to modern sustainability standards in a quick, easy, and affordable way — without having to renovate entire buildings.