Heating and cooling with a heat pump. The comfort and cosiness achieved when heating with a heat pump is no different than a conventional heating system based on oil, gas, or wood as the energy source. Like no other heat source, they combine particularly high energy efficiency with environmentally friendly heat generation. They use free, regenerative energy from the air, the ground, or groundwater as a heat source. For you this means: When you decide in favour of a heat pump, you are deciding on a cost-effective, sustainable, and future-proof heating system.