The most effective choice!
For geothermal heating having used underground collector or driven well - the most efficient for 80-800 m2 when the outdoor temperature up to -18 °С (as with under-floor heating, as with radiators) - inside coolant working temperature = 55 °C.
Average efficiency: 1 kW of electric power produces 4 kW of heating power.
In case of outdoor temperature -20 °С some additional heating sources is recommended to keep comfortable temperature conditions.
Allowing to cool apartments during hot summer season. The under-floor coolant temperature must not be lower 18 °С – to avoid condensed moisture (in case of radiators some collectors for moisture or fancoil are required.