Heat pump calculator — savings and payback period

It compares annual gas heating cost (demand × gas price) with heat pump cost (demand ÷ COP × electricity price). The difference is the annual saving, and payback = installation cost ÷ annual saving.

COP (Coefficient of Performance) is the ratio of heat output to electrical energy consumed. Air-to-water heat pumps: COP 2.5–4.5; ground-source (brine-to-water): COP 3.5–5.5. A higher COP means lower running costs.

Air-to-water split: PLN 25,000–50,000; air-to-water monobloc: PLN 20,000–40,000; ground-source with vertical boreholes: PLN 40,000–80,000; ground-source horizontal collector: PLN 30,000–60,000. Prices include device, installation and commissioning.

At current Polish energy prices (electricity ~PLN 0.85/kWh, gas ~PLN 0.40/kWh) and COP = 3.5, payback is typically 8–15 years. It shortens with a higher COP, more expensive alternative fuel (heating oil ~PLN 0.55/kWh) or subsidies.

A heat pump is cost-effective when electricity price ÷ COP is lower than the alternative fuel price. At COP = 3.5 and electricity PLN 0.85/kWh: effective heat cost = 0.85 ÷ 3.5 ≈ PLN 0.24/kWh — cheaper than gas (PLN 0.40/kWh).

Rule of thumb: energy-efficient house (A+) 20–40 kWh/m²/year; modern house (built after 2000) 60–100 kWh/m²/year; old uninsulated house (pre-1980) 150–250 kWh/m²/year. For a 150 m² house at 80 kWh/m²/year: 150 × 80 = 12,000 kWh/year.

Main programmes: (1) Czyste Powietrze — up to PLN 31,500 for an air-to-water pump, up to PLN 37,500 for ground-source. (2) Moj Prad 5.0 — up to PLN 6,000 when combined with PV. (3) Thermomodernisation relief — up to PLN 53,000 deducted from PIT income tax base.

Gas boiler: lower upfront cost (PLN 8,000–20,000), simpler installation, but higher running costs at rising gas prices and local CO₂ emissions. Heat pump: higher upfront cost, lower running costs, no local emissions, requires low-temperature distribution (underfloor or oversized radiators). EU regulations from 2025 favour heat pumps in new builds.

Modern air-to-water heat pumps work efficiently down to -15°C (some to -25°C), but COP drops with temperature. At -10°C typical COP is 2.0–2.5 instead of 3.5. Ground-source pumps are more stable — ground temperature at 100 m depth is a constant ~8–12°C.

Electricity use = annual heat demand ÷ COP. Example: 15,000 kWh demand, COP 3.5: 15,000 ÷ 3.5 ≈ 4,286 kWh/year. At PLN 0.85/kWh that is about PLN 3,643/year vs PLN 6,000/year for gas — saving approximately PLN 2,357/year.