Ground source heat pumps extract heat from the ground through a ground loop system to provide heating for buildings. Solar thermal panels collect heat from the sun which is then used to heat water and store it in a hot water cylinder. Biomass heating uses biological materials like wood to provide a low-carbon source of fuel for heating. Passivhaus is a construction standard that emphasizes maximizing insulation, minimizing thermal bridges and air leakage, and using renewable energy sources to provide comfortable, energy-efficient buildings.