We started swapping light bulbs as they burnt out about 18 months ago, and now we are about 50% LED bulbs.
Since the days are shorter in November, we have our first year-on-year comparison in. We used 20% fewer Kilowatt Hours this past November in my house, saving $70 in one month.
(Maybe there is some other factor…not sure what it could be though. It was kind of warm I suppose…)
Our building’s fire stairs which are required by code to be on 24/7 cost us $400 per month…they’re already CFL bulbs. So the trick there is going to require motion-sensitive function I suspect.