Do you think the christmas lights add more to the electrical usage than the hot water heater?
If you understood anything about home energy use, the majority of homes use the most energy when heating water. That's why most homes that have more than 1 or 2 residents install solar-electric water heaters.
To compare that to ANY OTHER energy consuming system or device is irrelevant, since the comparison to a water heater will always have the heater come out on top of energy usage.
Having said that, I'd bet $20 the homes already have a solar water heating system. Some may also have PV systems. That's not the point. The Christmas lights are a night-time extravagance, and therefore are not using solar electric power. And unless batteries are now in common use for PV in that area, no sense going there, either.
When we conducted energy surveys in Hawaii, the first recommendation before any PV or AC installs was to replace the electric water heater with solar.
So, the water heater argument is ridiculous. If they are using all electric energy to heat their water AND run their massive holiday light displays, then they are even bigger hypocrites than I thought!
BTW, "hot water heater" is an oxymoron. You don't need to heat hot water. Hot water is already hot. You either need a cold water heater or a hot water cooler.

--g. carlin