Copyright 2005 Frank Andrews - Home - Lightbulb Index - Contact Email: Frank

A Short History of Electric Light

by Frank Andrews

The Efficiency of Various Light Sources

For comparison, an 1860 Oil lamp with a single flame produces approximately 2,500 lumens, see also press reports after tables.

Incandescent Lighting
(An approximate lumen output is given for a Standard size bulb)
  Edison’s first bulb 1.4 lumens per watt.
  Best carbon filament.16 cp. bulb = approx. 50 lumens 3 to 4 lumens per watt.
  Cruto’s synthetic carbon 4 lumens per watt.
  Cruto’s deposited graphite 3 lumens per watt.
1905 Metallised carbon filament.
Annealed carbon by Willis Whitney.
4 to 5 lumens per watt.
1897-1912 Nernst lamp 6 lumens per watt.
1907 Squirted Tungsten
30 cp. bulb = 240 lumens
8 lumens per watt.
1910 Drawn Tungsten
32 Watt bulb = 320 lumens
10 lumens per watt.
1912 ‘Half-Watt’ (Coiled filament)
40 Watt bulb = 480 lumens
12 lumens per watt.
1933 Coiled-coil, 10-15% better than coiled filament.
60 Watt bulb = 800 lumens
13 to 14 lumes per watt
1959 Tungsten-halogen
40 Watt bulb = 800 lumens
20 lumens per watt.
1986 Modern bulb (standard)
60 Watt bulb = 960 lumens
16 lumens per watt.
After 86 ??? to be determined 2003
Non-Incandescent Lighting
1898 Moore Tubes c. 8 lumens per watt.
1931 Low pressure sodium discharge 50 lumens per watt.
1938 Fluorescent (Calcium Tungstate) 30 lumens per watt.
1946 Fluorescent (Halophosphate) 60 lumens per watt.
1973 Three band 90 lumens per watt.
1986 Low pressure sodium discharge 200 lumens per watt.

Further Notes

Press reports in 1907 gave very detailed accounts of the cost savings of tungsten lamps:

The Standard, July 18th 1907.

Comparative cost per 1,000 hours of use.

Gas with incandescent burner consuming 4 cubic feet of gas would have cost 18s with gas at 3s per 1000 cubic feet.

An Osram tungsten lamp of 32 cp. and consuming 35 watts per hour would have cost 11s 8d with electricity at 4d per unit.

A Carbon filament lamp of 32 cp. and consuming 105 watts per hour would have cost 35s with electricity at 4d per unit.

A Tantalum filament lamp of 22 cp. and consuming 40 watts per hour would have cost 13s 4d with electricity at 4d per unit.

It is noted that with this cheaper light that ‘the poorer classes need no longer have there small, and often badly ventilated rooms, further vitiated by gas burners or oil lamps, since the new lamp brings the luxury of electric light within the reach of all.’

The Daily Telegraph. July 18th 1907.

Mentions the competition between gas and electricity, each stimulating the other. Incandescent lighting having led Auer von Welsbach to develop the incandescent gas mantle. The irony of Auer having then gone on to produce the first metal filament, osmium, lamp which was to lead to the demise of gas for lighting, did not go unnoticed by the reporter. It refers to tungsten bulbs as having twice the life expectancy of carbon bulbs and compares light outputs, one tungsten bulb being better than two carbon and still costing less to run.

Next Chapter - List of Inventors and Other of Importantance

Back to previous page