The technology behind the different types of heat pumps is largely the same, at least in principle. Only the heat sources differ from each other. A working medium, the so-called refrigerant, is preheated with the help of heat from the earth, air or water. However, since heat generation requires a higher temperature level than that provided by the heat sources, the refrigerant must be heated to a higher temperature using electrical energy (electricity).
Local conditions
Depending on the different heat sources and requirements that a specific heat pump system places on the local conditions, there are both advantages and disadvantages for the individual systems.
| SYSTEM | ADVANTAGES | DISADVANTAGES |
|---|---|---|
| Brine-water heat pump with ground collector | – State funding possible – Subsidies from the KfW possible – Earthworks can be carried out on your own – Saving of fossil fuels – Can be coupled with other renewable energies – Cooling and heating possible – Favorable tariffs for the heat pump electricity |
– high area requirement: about twice the space required by the collectors in relation to the room to be heated – efficiency depends on the soil conditions – limited flow temperature, heating must be optimized accordingly |
| Brine-water heat pump with geothermal probe | – State funding from the BAFA possible – Subsidies from the KfW possible – low area expenditure – saving of fossil fuels – can be coupled with other renewable energies – heating in winter and cooling in summer possible – lower electricity tariffs for the heat pump electricity |
– High development costs due to deep drilling – Permission required, both under mining and water law – Efficiency dependent on soil conditions – Limited flow temperature |
| Air Water heatpump | – Indoor and outdoor installation possible – Little space required for the technology – Can also be retrofitted in suitable old buildings with little effort – Can be coupled with other renewable energies – Use of reduced electricity tariffs possible |
– Danger of icing with outdoor installation and insufficient insulation – Outdoor installation usually requires an additional heating element in winter – Subsidy reduced by 50 percent – Maintenance effort through regular checking of the refrigerant circuit – Economic efficiency only given with good insulation |
| Water to water heat pump | – existing wells can be integrated – low operating costs – can also be retrofitted in suitable old buildings with little effort – state BAFA subsidy – constant heat source temperature – heating and cooling possible – favorable electricity tariffs for heat pumps |
– Permit required due to contact with groundwater – Efficiency dependent on water volume and quality – Loss of performance when groundwater levels fall |
| Air to air heat pump | – Efficient heat recovery, for example in a passive house – Space-saving and aesthetic thanks to concealed installation of the ventilation system – Favorable electricity tariffs for heat pumps |
– high operating costs due to inconstant heat source air. On frosty days, an additional heating system may be necessary – maintenance work through regular filter changes – only economical in suitable new buildings, then no state subsidies – with dual mode use with other heating systems, an air humidifier may be necessary |