MICHAEL LIO, BETTER BUILDER MAGAZINE. Fifty-seven minutes – that is the average time my teenager spends in the shower. Yes, the engineer in me compels me to analyze all the energy use in my household. Meanwhile, my youngest takes less than five minutes, but I’ll leave that story for another time. Hot water use varies from one household to another depending on the number of occupants, their behaviour, and an entirely separate, but very important contributing factor – how many teenagers you have. Read More.