Eternal discussion : is it worth turning off all the lights for 15 minutes in the afternoon ? Or does lighting a daylight consume more than 15 minutes of normal consumption?
Answer
Dear Mark
It’s definitely worth turning off the lights in the afternoon, even if it’s only for 15 minutes.
Incandescent lamps (which are otherwise not energy efficient at all) consume no more at start-up than with normal burning. This is also the case with LEDs.
Gas discharge lamps (such as energy-saving lamps and fluorescent lamps) require a slightly larger start-up current when igniting than when remaining lit. However, this is only the case for a few tens of milliseconds.
The extra energy for this corresponds at most to letting the lamp burn for a few seconds; with modern fluorescent tubes and energy-saving lamps with a power electronic ballast, this is even shorter, because smaller start-up currents are required.
The only negative effect is that the lifespan decreases slightly, but you will hardly see that effect.
Conclusion: don’t leave the lights on if no one is in the room.
Regards
Geert Deconinck
Answered by
Prof Geert Deconinck
(electric) energy and reliable ICT systems
Old Market 13 3000 Leuven
https://www.kuleuven.be/
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