Lighting: historical costs and energy efficiency?

This data-file assesses lighting solutions throughout history, quantifying energy efficiency (in lumens per watt and in percentage terms), plus the costs of lighting (in cents per 1,000-lumen-hours). The file goes back to 1800 and covers candles, whale oil, town gas, incadescent bulbs, halogen and LEDs.

The work culminates with LED lighting, tracing the record efficiency levels announced in recent years. Overall, the best LEDs now achieve over 80% useful energy efficiency, while lighting costs have fallen 100x over the past century.

Copyright: Thunder Said Energy, 2019-2023.