India, Jan. 22 -- Every winter, my utility bill reminds me that hot water is never free. In the store, electric, gas, and solar geysers all sound like safe choices, but the cost shows up later. Electric feels simple, gas feels fast, and solar feels sensible, yet each behaves differently when your home uses hot water every day.

I'm comparing them as if I'm buying one for my home. I'm looking at heating time, standby loss, and what you pay per month, not fancy claims. If you bathe alone and switch it off on time, electricity can be fine. If you need hot water for showers, gas may cost less. If you have roof space and daily use, solar can cut bills most overall.

An electric geyser is the easiest purchase to make because nobody warns you wh...