We have a 300W halogen up-lighter with built in dimmer. It also has a
50W bendy spotlight with dimmer.

I'm aware that 300W is a lot of electricity, and in fact, it's too
bright when on full - we tend to have it on 50% or less.

Does dimming a light reduce the electricity usage? Part of me says yes,
but another part of me is less sure.

I'm thinking of looking for a 150W lamp to go in there which would be
more reasonable - especially if dimming has little effect on electricity
consumption.

Thanks

D