Compact Fluorescent Lifetime in Household Use

Summary

Compact fluorescent lamps save little or no money when used for standard household evening lighting, and they are ecologically more costly than equivalent incandescent lamps. Government regulations to force their use everywhere are counterproductive with both financial and environmental accounting. Expensive brands seem to do no better than economy brands. High power lamps have much shorter lifetimes than advertised.

Details

Ontarians are being ordered to stop using 'wasteful' incandescent light bulbs and to use solely 'green' compact fluorescents. We are told that their higher initial cost will be repaid in lower energy costs and a greener planet.

True? Well ... not so far for lamps used for ordinary household lighting.

First, we need real data on lamp life, not the fictitious ratings being touted by manufacturers based on idealized operation in their own laboratories. Here's data on the lamps that have failed for me since November 2005, when I moved into a new house and started keeping an accurate record of the 37 lamps I installed there:

TypeRated HoursActual Hours%use
GE FLE7/2/CAM/827 7W60002190036510 hr/day aquarium
GE FLE7/2/CAM/827 7W60001160019310 hr/day aquarium
Rona UltraMini 13W60001160019310 hr/day aquarium
Philips EL/mdT 11W100001670016710 hr/day aquarium
Rona UltraMini 13W6000997016610 hr/day aquarium
Rona UltraMini 9W6000854014210 hr/day aquarium
Rona UltraMini 9W6000730012110 hr/day aquarium
Philips EL/mdT 11W1000082008210 hr/day aquarium
GE 20W FLE20TT3/8271500080005310 hr/day aquarium
GE 20W FLE20TT3/8271500059003910 hr/day aquarium
Sylvania CF23EL 23W120003688318 hr/day kitchen
Noma FLE26HT3/23100002422241 hr/day basement
Noma FLE26HT3/23100001879191 hr/day basement
Philips ELJdT 42W1200017801510 hr/day plants
Rona UltraMini 13W6000919151 hr/day basement
Philips Marathon 27W100001200121 hr/day basement
Philips EL/mdT 15W800070090.5 hr/day stairs
Luminus 13W 2913-E031000060062 hr/day bedroom
Globe Ultramini 9W600020030.2 hr/day hallway

Now we can calculate the dollar savings to actually expect. First, the average 1000 hr incandescent lamp produces 14 lumens/watt, the average compact fluorescent 60 lumens/W. So, each watt to a compact fluorescent saves 3.3 watts compared to an incandescent. Home electricity in Ottawa Ontario costs 12c/KWH (mid-2009, GST and kWh-derived costs included). Electricity used within our homes during our heating season saves on home heating fuel, but adds to air conditioning costs during the summer. The length of the heating season is 7 months in Ottawa, the cooling season 2 months, so this factor will slightly decrease the energy savings calculated below.

Standard 60 W incandescent lamps cost $0.92 (taxes included) and last 1000 hours, so a fluorescent lamp that lasts 8000 hours saves $7.36 in replacement cost.

TypeHoursCostKWH savedlamps savednet savinguse
Philips EL/mdT 11W167005.6960616.782.4210 hr/day
GE FLE7/2/CAM/827 7W219003.9950121.976.8710 hr/day
Rona UltraMini 13W11602.8049711.667.5110 hr/day
Rona UltraMini 13W99702.804271057.6410 hr/day
GE 20W FLE20TT3/827800021.79528848.9310 hr/day
GE FLE7/2/CAM/827 7W116003.9926811.638.8410 hr/day
Philips EL/mdT 11W82005.692988.237.5710 hr/day
Rona UltraMini 9W85402.802548.535.5010 hr/day
Sylvania CF23EL 23W36885.702803.731.308 hr/day kitchen
GE 20W FLE20TT3/827590021.793895.930.3710 hr/day
Rona UltraMini 9W73002.802177.329.9610 hr/day
Noma FLE26HT3/2324225.082102.422.461 hr/day household
Philips ELJdT 42W178014.682471.816.5610 hr/day
Noma FLE26HT3/2318804.581611.916.491 hr/day household
Luminus 13W 2913-E036003.41260.60.232 hr/day household
Philips Marathon 27W12004.50301.20.171 hr/day household
Philips EL/mdT 15W7005.69350.7-0.880.5 hr/day household
Rona UltraMini 13W9192.8030.9-1.611 hr/day household
Globe Ultramini 9W2002.8060.2-1.900.2 hr/day household

As you can see, the less the daily use, the less money is saved. That's because turning a fluorescent light on causes at least as much wear on the lamp as an hour of running.

The Sylvania CF23EL lamp package features the statements, "Save $184 in energy costs", and "Lasts 11 Years!". The actual lifetime was 1.3 years for the bulb above, the energy cost saving $31.30

Modern compact fluorescents weigh twice as much as an incandescent of similar lumen output (the earlier ones weighed up to ten times as much) and the materials of which they are made are much more toxic, so the environmental costs of production and disposal are much higher. Not only is there mercury in them, but the phosphors exposed when the glass is broken in a landfill are even more toxic than the mercury.

In short, compact fluorescent lamps save little if any money when used for standard evening household lighting, and they are ecologically more costly than equivalent incandescent lamps. They should only be used when left on for many hours at a time. Government regulations to force their use everywhere are counterproductive with both financial and environmental accounting.

John Sankey