In Mühltal, in the German state of Hesse, a detached house built in the 1970s was refurbished in 2011 to become an 'energy surplus' home, capable of generating more energy than it requires for its operation. The energy+Home1.0 case stands out for addressing carbon neutrality through a strategy that prioritises reducing energy demand rather than the large-scale deployment of new technologies.

The intervention focused on minimising consumption through comprehensive rock wool insulation and the replacement of windows, significantly improving the thermal performance of the building envelope. Ventilation is optimised through a central heat recovery unit that reduces losses associated with air renewal. For heating, an air-to-water heat pump is used, complemented by a wood-burning stove, a heat exchanger, and low-temperature radiant panels. The electricity required to operate the building’s systems is supplied by a solar installation located on the roof.

Key figures:

• Building condition: Refurbished residential building from the 1970s
• Building type: Residential single (detached house)
• Delivery year: 2011 (construction/refurbishment date)
• Primary energy consumption: Not specified on the page
• Energy performance certificate rating: Not specified on the page
• Renewables: Solar energy unit

_{Source of the picture: World Green Building Council (Credit not specified)}