Berlin – September 15, 2026 -- Homeowners weighing a heating system upgrade are being pointed underground, as geothermal heat pumps promise lower long-term costs despite steeper installation prices. A new short study by consulting firm Prognos, commissioned by the Bundesverband Geothermie, the Erdwärmegemeinschaft Bayern, and the Bundesverband Wärmepumpe (BWP), finds that ground-source systems can undercut air-source heat pumps by roughly 8 percent in total annual costs over a 20-year period.