Heat-transfer fluids and heat pipes: Correlation
Prices it moves with, and why
Heat-transfer fluids include water, glycols, thermal oils, silicone fluids and molten salts, alongside copper heat pipes. Their prices follow the raw material behind each, mostly oil-based chemicals, nitrate salts or copper, and the demands of each application.
No public price Heat-transfer fluids and heat pipes has no public monthly price series: Many different fluids and products; no single price series.What its price moves with
Ethylene glycol mixed with water is the standard antifreeze coolant in engines, chillers and solar heating loops. Its price follows the ethylene and oil cycle, so coolant costs move with petrochemical markets.
Not enough overlapping price history to measure.High-temperature synthetic thermal oils, such as the biphenyl and diphenyl oxide mixture used in solar thermal plants, are made from benzene. Their price therefore follows aromatics and, through them, crude oil.
Not enough overlapping price history to measure.Silicone heat-transfer fluids work across a wide temperature range and last a long time. Their cost depends on silicon metal and methanol, the inputs to silicone production, which China dominates.
No public price for silicones, so the link is explained in words only.Molten salt carries and stores heat in solar thermal plants, using a mix of sodium and potassium nitrates. Potassium nitrate draws on potash, so fertiliser markets affect the cost of filling a salt system.
Not enough overlapping price history to measure.Heat pipes in electronics and solar collectors are usually copper tubes holding a small amount of working fluid. Copper is the main material, so its price drives heat pipe costs.
Not enough overlapping price history to measure.Concentrated solar power plants use thermal oil or molten salt as both carrier and store. Growth in such plants is the main source of demand for large volumes of molten salt and high-temperature oils.
No public price for concentrated solar power, so the link is explained in words only.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.