Running cost - Dimmed lighting

[Simon D.]

I have x6 50w halogen down lights in my lounge. I now have a dimmer fitted and my friend says that it costs the same to run these whether they are dimmed or not...is this true?

[heathfield]

Your friend is wrong. The dimmer reduces the amount of power provided to the lights. That's why they dim. A modern solid state dimmer cuts off part of the AC cycle supplied to the lights, thus cutting off part of the power the lights would otherwise use.

[buildersmate]

Agreed. It's the friend who is dim, not the lights.

[carlton23]

That answer settles an argument I`ve had in the past........Thankyou..... both.

[buildersmate]

The other advantage is that the bulbs will probably last longer, because the most stress is put onto a bulb at initial switch-on, and having a dimmer in the circuit in most cases does not zap 240V straight across the bulb. instantaneously - even if the dimmer spindle is turned high. The voltage rises quickly but not instantly.

[Tweed]

Depends on the dimmer. The old rheostat/voltage divider type will use as much power whether dimmed or not, but the newer type operates by fast switching or something like that and are much more efficient.