What does LED lighting cost in electricity per year?

LED uses little, everyone knows that. But how little exactly, and where is the difference with what you had? Here is the calculation, with current prices.

The calculation

Multiply the power in watts by the number of hours it is on per year, divide by a thousand, and multiply by the price per kilowatt hour.

An example. A 12-watt pendant lamp that is on four hours a day comes to 1,460 hours a year. That is 12 times 1,460 divided by a thousand, or just over 17 kilowatt hours. At a rate of 30 cents, that lamp costs you about five euros a year.

The difference with the past

The same amount of light cost you almost twenty-six euros a year with a 60-watt incandescent bulb. With halogen about eighteen euros. So the difference is not in cents but in multiples.

If you have ten light points at home that are on every day, you are talking about two hundred euros a year difference.

Why watts say nothing about light

Watts are consumption, not light output. Two 12-watt lamps can differ greatly in how much light they give. So always look at lumens. See how many lumens you need per room.

A good LED nowadays achieves a hundred lumens or more per watt. We would not go below seventy.

What dimming does to consumption

Dimming lowers consumption roughly proportionally: at fifty percent you use roughly half. That saves not only electricity but also extends the lifespan, because the lamp stays cooler.

And the purchase price?

An LED that lasts fifteen years and costs five euros a year is cheaper over its lifetime than a series of cheap lamps you replace every two years. So do not calculate a lamp by its purchase price alone, but by what it costs you for as long as it hangs.

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