Heat Pump Cost Calculator

FAQ

How does outdoor temperature affect heat pump efficiency?

Heat pump COP (Coefficient of Performance) decreases as outdoor temperature drops. At 7°C, a typical air-source heat pump achieves COP 4.5. At -10°C, COP may drop to 2.5-3.0. This is why winter months cost more to heat. Ground-source heat pumps maintain more stable COP year-round.

What is the difference between COP and SCOP?

COP is efficiency at a specific temperature point (e.g., COP 4.0 at 7°C outdoor). SCOP (Seasonal COP) is the weighted average efficiency across the entire heating season, accounting for varying temperatures. SCOP is more realistic for annual cost calculations.

Is a heat pump worth it compared to gas heating?

It depends on your electricity-to-gas price ratio. If electricity costs less than 3-4x gas per kWh, heat pumps typically save money. With a SCOP of 3.5, you get 3.5 kWh of heat for every 1 kWh of electricity. Factor in installation costs and available incentives for a complete picture.

Why do heat pump costs vary so much by month?

Two factors: heating demand and efficiency. In winter, you need more heat AND the heat pump works less efficiently (lower COP due to cold outdoor temps). January might cost 5-10x more than October. This is normal for air-source heat pumps.

How accurate is this heat pump cost calculator?

This calculator uses realistic temperature-dependent COP curves and climate data. Results are typically within 15-20% of actual costs. Real costs depend on your specific heat pump model, house insulation, thermostat settings, and local weather patterns.

Should I choose radiators or underfloor heating with a heat pump?

Underfloor heating is more efficient with heat pumps because it requires lower water temperatures (35°C vs 50°C for radiators). Lower supply temperature = higher COP = lower running costs. Underfloor can improve SCOP by 25-35% compared to radiators.

How much can I save with a night tariff or solar panels?

With off-peak electricity or solar PV, you can reduce heat pump running costs by 30-50%. This calculator includes low/average/high price scenarios. If you have solar panels, use the "Low" scenario to estimate costs when running the heat pump during sunny hours.

Which heating system is cheapest: heat pump, gas, or pellets?

It varies by region and current fuel prices. Heat pumps are usually cheapest where electricity is affordable relative to gas. Pellets can be very competitive in rural areas with cheap biomass. Use the system comparison section to see which is cheapest for your specific fuel prices.

What size heat pump do I need?

As a rough guide: 50-80W per m² for well-insulated homes, 80-120W for average insulation, 120-150W for poorly insulated. A 150m² average home typically needs 12-15kW. Get a professional heat loss calculation for accurate sizing.

Do heat pumps work in very cold climates?

Modern air-source heat pumps work down to -25°C or lower, though efficiency drops significantly below -15°C. In very cold climates, ground-source heat pumps or hybrid systems (heat pump + backup boiler) are often more practical and cost-effective.

What is the difference between ASHP and GSHP?

Air-Source Heat Pumps (ASHP) extract heat from outdoor air. They cost $10,000–$20,000 to install and are easier to retrofit. Ground-Source Heat Pumps (GSHP) use stable ground temperature (~10°C year-round) via buried pipes, costing $20,000–$40,000. GSHP maintains consistent COP of 4.0–5.0 year-round, while ASHP efficiency drops in very cold weather. For most homes, ASHP offers the better ROI; GSHP shines in very cold climates.

How much does annual heat pump maintenance cost?

Heat pumps need minimal maintenance: annual service check ($100–$200), filter cleaning (free, DIY), and refrigerant checks every few years. Total annual maintenance averages $150–$300 — far less than gas boilers ($300–$600/year) or oil boilers ($400–$700/year including oil tank service). Modern heat pumps are highly reliable with few moving parts.

How noisy is a heat pump?

Modern heat pumps operate at 40–60 dB(A) — similar to a refrigerator or conversation. Premium models run as quietly as 40 dB. Noise depends on model, installation quality, and operating mode. Position the outdoor unit away from bedroom windows and use anti-vibration mounts. GSHP systems have no outdoor unit and are nearly silent indoors.

How long does a heat pump last?

Well-maintained heat pumps typically last 15–20 years. ASHP units: 15–20 years. GSHP ground loops: 25–50 years (the ground loop outlasts the heat pump unit). For comparison: gas boilers last 10–15 years, oil boilers 15–20 years. Factor lifespan into your payback calculations — a 20-year heat pump typically delivers 8–12 years of net savings after payback.

What is a hybrid heat pump system?

A hybrid system pairs a heat pump with a gas boiler backup. The heat pump handles most heating; the boiler only fires when outdoor temps fall below a "bivalent point" (typically -5°C to -10°C). This reduces running costs by 40–60% vs a boiler alone, with lower installation cost than a full GSHP. Ideal for homes that cannot achieve optimal heat pump performance due to older radiators or very cold climates.

Can a heat pump heat domestic hot water (DHW)?

Yes. Most modern heat pumps include hot water production. However, DHW requires higher water temperatures (55–60°C) than space heating (35–50°C), which reduces efficiency. Many systems use a separate DHW tank with a backup immersion heater for "Legionella kill" cycles. DHW can add 15–30% to annual heat pump electricity consumption.

How do solar panels combine with a heat pump?

Solar PV + heat pump is a powerful combination. Run the heat pump during peak solar production (10 am–3 pm) to heat your home and hot water at near-zero electricity cost. With a smart controller or immersion diverter, you can store solar energy as heat. In well-insulated homes, solar can cover 30–60% of heat pump electricity needs annually, dramatically reducing running costs.

Can a heat pump also cool in summer?

Most modern heat pumps are reversible — they can cool in summer by running the refrigerant cycle in reverse. Air-to-water heat pumps can cool via underfloor systems (chilled water circulation) or fan coil units. Air-to-air heat pumps cool just like air conditioning. Summer cooling adds modest electricity consumption but improves the overall year-round value proposition.

Do heat pumps work in old buildings?

Yes, but efficiency depends on insulation quality. In poorly insulated buildings, you need a larger heat pump and higher supply temperatures, reducing COP. Improving insulation first (loft, cavity walls, double glazing) can reduce heat demand by 30–50%, allowing a smaller, more efficient heat pump. The "heat pump first or insulation first?" answer is usually: insulate first, then right-size the heat pump.

What government incentives are available for heat pumps?

In the US: Federal Tax Credit (25C) covers 30% of heat pump costs up to $2,000/year. Many states offer additional rebates ($500–$3,000). The Inflation Reduction Act (2022) enhanced these incentives. In the EU: most countries offer 30–45% grants (BEG in Germany, MaPrimeRénov in France, Czyste Powietrze in Poland). Always check current programs as they change frequently — incentives can cut net installation cost by 25–45%.

What electricity price makes a heat pump cost-effective vs gas?

The key ratio is electricity-to-gas price per kWh. With a SCOP of 3.5, your heat pump delivers 3.5x more heat per unit cost than direct electric. For break-even with gas: electricity price must be less than (gas price × SCOP). Example: gas at $0.08/kWh → heat pump cost-effective if electricity < $0.08 × 3.5 = $0.28/kWh. Most US and EU electricity rates fall within this range.

What is the difference between air-to-water and air-to-air heat pumps?

Air-to-water heat pumps produce hot water for radiators, underfloor heating, or DHW tanks — they integrate with existing wet heating systems. Air-to-air heat pumps (like mini-splits) blow warm or cool air directly into rooms — simpler to install, no wet system needed, but cannot produce domestic hot water. For whole-home central heating in colder climates, air-to-water is usually preferred; air-to-air excels in mild climates or for room-by-room control.