# Ambient heat: Correlation Prices it moves with, and why Source page: https://www.materialinsights.org/energy/e_ambient/correlation/ Ambient heat in air, ground and water is free, but it is low-grade and must be lifted by heat pumps using electricity. Its value depends on heat pump cost, power prices and the gas or oil heating it displaces. No public price Ambient heat has no public monthly price series: A free natural flow; no market price, only capture costs. #### What its price moves with Energy [HP Heat pumps, air conditioning and refrigeration](https://www.materialinsights.org/energy/e_heat_pumps/)Main converter Heat pumps and air conditioners move ambient heat into or out of buildings, delivering several units of heat for each unit of electricity. Heat pump prices and efficiency decide how much ambient heat is worth using. Not enough overlapping price history to measure. Energy [GSH Geothermal direct use and ground-source heat pumps](https://www.materialinsights.org/energy/e_geo_direct/)Main converter Ground-source heat pumps draw on the steadier temperature a few metres underground. They cost more to install than air-source units but run more efficiently in cold climates. Drilling or trenching is the main extra cost. Not enough overlapping price history to measure. Energy [Bld Energy in buildings](https://www.materialinsights.org/energy/e_buildings/)Running cost Using ambient heat needs electricity to drive the compressor, so power tariffs decide running costs. Where electricity is cheap relative to gas or oil, heat pumps win. Time-of-day tariffs can lower this cost further. Not enough overlapping price history to measure. Energy [Gas Natural gas](https://www.materialinsights.org/energy/natural_gas/)Rival source Gas boilers are the main rival for space and water heating in Europe and North America. High gas prices, such as in 2022, made ambient heat through heat pumps much more attractive. Not enough overlapping price history to measure. Chemical [HFC Fluorochemicals and refrigerants](https://www.materialinsights.org/chemicals/fluoro_intermediates/)Working fluid Most heat pumps use fluorinated refrigerants, and phase-down rules on high-warming gases shift designs to new refrigerants or propane and CO2. Refrigerant cost and rules affect equipment prices. Refrigerant leaks also add to service costs. Not enough overlapping price history to measure. Commodity [Cu Copper](https://www.materialinsights.org/commodities/copper/)Capture cost Heat exchangers, compressor motors and piping in heat pumps use copper. Copper prices feed into the cost of every unit sold. Some makers switch to aluminium tubes when copper prices are high, though copper transfers heat better. Not enough overlapping price history to measure. How to read these numbers **Correlation of monthly changes** (the number in the coloured pill) compares how much each price moved, month by month, since 2006 or the first month both series exist. It runs from −1 to +1: near +1 the two usually rise and fall in the same months, near 0 there is no link, and a negative number means they tend to move in opposite directions. Above 0.7 is strong, 0.4 to 0.7 moderate, 0.2 to 0.4 weak. **12-month changes** compare year-on-year moves, which shows whether two prices share the same cycles even when the month-to-month noise differs. **Price function** is a straight-line fit of the two prices on logarithmic scales: price ≈ k × (partner price)^β. β is how much this price moves, in per cent, for a 1% move in the partner over the whole period, and R² is the share of the variation the fit explains. Two prices that both drift up with inflation can fit well without any real link, so read it together with the monthly correlation. **Lead or lag** checks whether the monthly correlation is clearly higher when one price is shifted by 1 to 6 months. Correlation is not cause. The reasons on each card explain the economic link; the numbers show how strongly it has shown up in prices. Proxy series are US producer price indexes or related prices and can blur the real link. Data: World Bank Commodity Price Data (Pink Sheet), October 2026; US Bureau of Labor Statistics producer price indexes, IMF primary commodity prices and US EIA prices via FRED, Federal Reserve Bank of St. Louis, retrieved November 2026. Calculations by this site. ## Other sections - [Summary](https://www.materialinsights.org/energy/e_ambient/index.md) - [Overview](https://www.materialinsights.org/energy/e_ambient/overview/index.md) - [How energy resides](https://www.materialinsights.org/energy/e_ambient/resides/index.md) - [Abundance](https://www.materialinsights.org/energy/e_ambient/abundance/index.md) - [Fluctuation in time](https://www.materialinsights.org/energy/e_ambient/time/index.md) - [Across the Earth](https://www.materialinsights.org/energy/e_ambient/geography/index.md) - [Impact on nature](https://www.materialinsights.org/energy/e_ambient/nature/index.md) - [Relationships](https://www.materialinsights.org/energy/e_ambient/links/index.md)