# Passive solar and natural cooling: Correlation

Prices it moves with, and why

Source page: https://www.materialinsights.org/energy/e_passive/correlation/

Passive solar design and natural cooling use orientation, shading, thermal mass and ventilation to cut energy use. It has no price of its own; its value equals the cooling and heating energy it saves.
 No public price Passive solar and natural cooling has no public monthly price series: A design approach; no traded price.

#### What its price moves with

 Energy [HP Heat pumps, air conditioning and refrigeration](https://www.materialinsights.org/energy/e_heat_pumps/)Substitute

Good shading, ventilation and insulation reduce the need for air conditioning. As cooling demand grows in India, passive design saves both equipment and power costs. It also cuts peak demand on the grid.
 Not enough overlapping price history to measure.

 Energy [Bld Energy in buildings](https://www.materialinsights.org/energy/e_buildings/)Running cost

The value of passive design is the electricity and fuel it saves over a building's life. Higher power tariffs make these savings larger. These savings repeat every year, so even small changes add up over decades.
 Not enough overlapping price history to measure.

 Commodity [Cem Cement](https://www.materialinsights.org/commodities/cement/)Thermal mass

Heavy concrete and masonry walls store heat by day and release it at night. Cement costs affect how much thermal mass a building can include. Earth, stone and brick also serve, often at lower cost.
 Not enough overlapping price history to measure.

 Chemical [TiO2 Titanium dioxide](https://www.materialinsights.org/chemicals/titanium_dioxide/)Cool coatings

Cool roof paints use titanium dioxide pigment to reflect sunlight and cut heat gain. Pigment prices affect the cost of these coatings. Cool roofs can lower indoor temperatures in hot Indian cities and cut cooling bills.
 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_passive/index.md)
- [Overview](https://www.materialinsights.org/energy/e_passive/overview/index.md)
- [Efficiency](https://www.materialinsights.org/energy/e_passive/efficiency/index.md)
- [Techniques](https://www.materialinsights.org/energy/e_passive/techniques/index.md)
- [Resources and labour](https://www.materialinsights.org/energy/e_passive/resources/index.md)
- [Impact on the biosphere](https://www.materialinsights.org/energy/e_passive/biosphere/index.md)
- [Relationships](https://www.materialinsights.org/energy/e_passive/links/index.md)