A chart exists showing the historical cost of an hour of light at night, with early data points at about 5 hours of labor per hour of light.

Judged as of 2026-09-04. True if a published chart or dataset exists (e.g. William Nordhaus's 'Do Real-Output and Real-Wage Measures Capture Reality? The History of Lighting', or Our World in Data charts based on it) showing the historical labour or monetary cost of artificial light over time, with early data points at roughly 5 hours of labour per hour of light (about 4-6 hours counts). Mostly true if such a chart exists but the early data point is noticeably different from about 5 hours (e.g. stated in different units, or roughly 2-10 hours for comparable light). Mostly false if such a chart exists but its early data points are far from 5 hours of labour per hour of light. False if no chart of the historical cost of light exists.

Set before the research began.

1. E1 Lighting Costs Near Nothing Now HumanProgress.org · 29 March 2023

   “Nordhaus estimates that our Paleolithic ancestors labored 58 hours, mostly gathering wood, to “buy” 1,000 lumen-hours of light. (A lumen- hour is a unit of luminous energy, equal to that emitted in 1 hour by a light source emitting a luminous flux of 1 lumen.) By 1800, it took about 5.4 hours, and by 1900, it took 0.22 hours.”

2. E2 Do Real-Output and Real-Wage Measures Capture Reality? The History of Lighting Suggests Not William D. Nordhaus, in Bresnahan and Gordon (eds), The Economics of New Goods, NBER and University of Chicago Press · 1996

   “Labor price of light: true and traditional”

3. E3 The price of lighting has dropped over 99.9% since 1700 Our World in Data · 18 June 2026

   “In the early 14th century, one million lumen-hours — a standard lighting measure — would have cost around £34,000 in 2000 prices. By 2023, this had fallen to £2.15, a 16,000-fold decline.”

E2 is Nordhaus's 1996 chapter with a chart titled "Labor price of light: true and traditional", and E3 is a 2026 Our World in Data chart of the price of lighting over time, so a published chart of the historical cost of light exists. E1 reports Nordhaus's figure of about 5.4 hours of labour around 1800. That figure is per 1,000 lumen-hours, not per hour of light, and the earlier Paleolithic figure is 58 hours. E3 gives its early figures in pounds rather than in hours of labour. Because the roughly 5-hour figure is in different units from the claim's "hour of light", the criteria's mostly-true category applies.