Building heat recovery: Correlation
Prices it moves with, and why
Heat recovery ventilation, heat-pump water heaters and drain-water recovery are sold as building equipment. The proxy is the US air-conditioning and heating equipment index, which follows metals, compressors and labour. Their value is the gas or electricity saved.
Proxy US PPI: air-conditioning, refrigeration and forced-air heating equipment index · monthly, Jan 2006 to Sep 2026There is no free public price for building heat recovery itself, so this tab uses the closest public series as a stand-in. Read the numbers as an indication, not as the price of this exact item.
What its price moves with
Selected linkBuilding heat recovery and Energy in buildings
Monthly changes 0.14 little or none correlation 12-month changes 0.70 moderate correlation Last 5 years 0.22 monthly changes Lead or lag none No clear lead or lag Price function, Jan 2006 to Sep 2026 Building heat recovery ≈ 4,750 × (Energy in buildings)1.61 R² 0.91 On this fit, a 10% higher energy in buildings price goes with a 16.6% higher building heat recovery price over the long run. Units: index and US$/kWh.Chart: Building heat recovery and Energy in buildings prices rebased to 100 at Jan 2006, log scale
Both prices rebased to 100 at Jan 2006, on a log scale so equal percentage moves look the same size.Chart: Building heat recovery price against Energy in buildings price, monthly, log scales, with fitted line
Each dot is one month; paler dots are older (2006), darker dots recent (2026); the ringed dot is the latest month. The dashed line is the fitted price function. Both axes are logarithmic.Recovery units cut heating, cooling and hot water bills, so household power and gas prices set their value. Yearly moves correlate at 0.70 with the electricity proxy, mostly a shared US inflation trend.
little or none co-movement month to month · 248 months Show chartsIn gas-heated buildings, recovering ventilation and drain heat cuts gas use, so dear gas improves payback. Yearly moves correlate at 0.53 with European gas, while monthly moves hardly correlate, as equipment prices react slowly.
little or none co-movement month to month · 249 months Show chartsHeat recovery ventilators use thin aluminium plate or rotary wheel exchangers. The link barely shows, with monthly moves correlating at 0.01, as aluminium is a small part of finished units sold on annual price lists.
little or none co-movement month to month · 249 months Show chartsDrain-water heat recovery units and heat-pump water heaters use copper pipe and coils. The equipment index shows correlations close to zero with copper, because makers smooth metal costs through contracts.
little or none co-movement month to month · 249 months Show chartsPlate and coil exchangers are the heart of every recovery unit. Monthly moves correlate at 0.26 and yearly at 0.81 with the heat exchanger index, a common driver from US equipment costs.
weak co-movement month to month · 249 months Show chartsHeat-pump water heaters use refrigerants, many still fluorinated, though natural ones such as propane and carbon dioxide are spreading. Monthly moves correlate at only 0.12 with the fluorocarbon proxy, showing little link.
little or none co-movement month to month · 207 months Show chartsHow 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.