Solar panels and heat pump: the combo that actually saves

A modern heat pump delivers 4 kWh of heat per 1 kWh of electricity (COP 4). If that kWh comes from the sun, heating and cooling becomes nearly free. Solar + heat pump is the most profitable retrofit in 2026.

Real heat pump consumption

12 kW thermal for 1000 sqft: pulls 3 kW electric (COP 4) in mild weather. Extreme winter (23 °F) drops to COP 2.5 → 4.8 kW electric. Annual: 3000-5000 kWh for a typical EU home, 5000-8000 in US/Canada.

How many panels you need

Cover 4000 kWh/year of heat pump: 3-4 kWp (8-10 panels of 410 W) in sunny climate. Northern climates: 5-6 kWp. Note: in winter you produce less exactly when you need most heat.

The winter-summer mismatch

Summer: you produce double yearly average and use a lot of cooling. Perfect match. Winter: half production, lots of heating. So oversize panels and/or have net metering active.

Smart scheduling

Run heat pump for DHW and radiant floor preheating during midday (when sun is up). Free if you have surplus. 200-300 L hot water tank works as cheap thermal battery.

Radiant floor vs radiators

Heat pump + radiant floor: COP 4-5 (best possible combo). Heat pump + conventional radiators: COP 2.5-3 (doesn't exploit optimal low temp). If investing in heat pump, plan radiant floor in parallel.

ROI with solar

Heat pump 8-15 kW: $8000-15000. Solar 4-5 kWp: $7000-11000. Total: $15000-26000. Tax credits cut 30-40%. Payback 7-10 years in EU/US. After: 20+ years of nearly-free climate control.

Read more in solar and AC and available rebates.