Median income and take home pay should be brought into account though. California has one of the highest even by US standards so a $1000 bill for the median Californian family feels much less expensive than for the median Manchester family.
There are no median families. There are a lot of very high wage earners in CA.
You should really be looking for the mode here.
I agree, the mode is probably better. Anyway from the median you can also get a good guess of how much income the band sitting between 25%-75% has since it's a normal distribution. Either comparison should be ok for a guesstimate of the impact of electricity bills for a family in California vs different parts of the UK.