Ambient heat
Low-temperature heat held in air, ground and water, mostly from the Sun.
Natural sources · Solar-derived flows · No. 9
- Natural sources
- Origin: Indirect solar
- Renewable: Yes
Even freezing air holds heat: a heat pump can deliver three to four units of warmth for each unit of electricity.
Chart: Illustration: Ambient heat
Where it comes from
Chart: Map of where it comes from
Air, soil and water hold low-grade heat, almost all absorbed sunlight; a heat pump uses electricity to move it indoors rather than making heat.
Three things to know
- Europe sold about 2.3 million heat pumps in 2024 across 19 countries, after a 22% fall from 2023.
- Cold-climate heat pumps still reach an efficiency above 1.5 near -30 °C, up to double plain electric heating.
- In 2025 Germany saw heat pumps outsell gas boilers for the first time.
The journey
- 1 SunlightWarms air, shallow ground and water
- 2 Ambient heatToo cool to use directly
- 3 Heat pumpElectricity lifts the heat to useful temperatures
- 4 Warm homesSpace heating, hot water, also cooling