Frugal and Energy Efficient Living

Mine is only ten gallons and I can get about a five minute shower with it fairly warm if not scorching and six or seven if I go for lukewarm.

There are two reasons a tankless is more efficient, first is you aren't storing hot water with the attendant heat leakage from the tank through the insulation, the second is because the tankless is usually put right where the hot water is used so you don't waste hot water in the pipe getting there, both when you turn the hot water on and when you turn it off.