### Capacity Sizing: The Main Rule Choosing the right heat pump starts with calculating the building's heat loss. On average, a modern well-insulated home requires 0.05–0.07 kW per m².
### Calculations for Different Areas
**100 m² home:** The optimal choice is a model with 6–8 kW capacity. This provides comfortable heating even on frosty days and hot water preparation.
**150 m² home:** A 10–12 kW unit is recommended. The number of occupants should be factored in to meet DHW demand.
**200 m² home:** A capacity of 14–16 kW is required. For these areas, three-phase models are often used for stable grid operation.
### Why Not to "Buy Big"? Excessive capacity leads to "cycling" — frequent compressor on/off switching, which shortens equipment life. Termojet recommends inverter models that modulate capacity smoothly.
Also pay attention to the heating distribution system — low-temperature radiators or underfloor heating are ideal partners for a heat pump.