Tuesday, December 13, 2011

Hot showers

There are three reasons why our hot showers cost more in the winter than in the summer.

The first is that the water coming into the heater is colder, so the heater has to do more heating.  Clearly, it'll take more energy to heat the water if it starts at a chilly 35° than if it starts at a balmy 80°.

The second reason is that the cold water you mix it with is colder, too, so you need more hot water to offset the cold water.  For example, in the summer you might mix cold (80°) and hot (120°) water equally, and you'd get 100° water -- a little warmer than body temperature, so pretty comfortable.  But if you mix winter cold water with equal parts of hot water (mixing 40° and 120° water), you'd have 80° water. That's swimming pool temperature -- pretty chilly!  Most people use less cold and more hot water instead.

The third reason is that the surrounding air is colder, so you're likely to take hotter showers in the winter than in the summer, just to keep the body comfortable.

How to spend less money?  Let's take the last issue first.  Keep the tub and room a little warmer by closing the drain while you shower (even tossing a washcloth down on the drain keeps some water in).  The warm water will help to warm the tub a bit, and warm feet helps your whole body feel warmer.  It might also help warm the bathroom enough that you don't need to shower longer than usual just for warmth.  You can let the tub drain out after you are done with your shower.

Turn the knob on the thermostat
to adjust temperature.

You can reduce the amount of work your water heater has to do by lowering the thermostat on it, if you haven't already.  Keep your water heater thermostat at 120°F, the lowest temperature that still kills germs.  If you've never changed the setting on your thermostat, this might seem scary or unfamiliar . . . but spending 5 minutes on this can mean saving lots of money and fuel, so gird up those loins and do it!  (See this US Dept of Energy page for why this lower temp helps your heater last longer, too.  Bonus!)

Tighten with a wrench.  Done!

Screw the new spigot on just like a light bulb.
And to use less water, you can install a low-flow shower head.  If you haven't done much plumbing before, you'd be surprised how easy this is -- it's almost exactly like changing a lightbulb.  You'll need a shower head, a wrench, and teflon tape.  You don't need to turn off the water main or anything.  Just use the wrench to unscrew the shower head, wrap a bit of teflon tape 2 or 3 times around the threads (this helps the new fixture slide on more easily), and screw the new shower head right on.  Tighten a bit with the wrench, and . . . Done!

For those of us who have mastered hot water 101 and want a little more challenge, here's an extra-credit  assignment (can you tell I'm gearing up for grading exams?):  Install a hot water heater timer.

These babies are like the programmable thermostats for your whole home.  They allow you to turn down the water temperature during times when you're not around (say, at night while you're sleeping), and then heat it back up when you'll need it.  I managed to install one myself several years ago, so I know it's possible as a DIY project, but honestly I don't remember if it was hard or easy to do.


  1. If the water heater is not needed, we turn it off to reduce the electric bill during summer season. I also make sure that the water heater is always working to make sure that we have enough hot water during the cold season. It would be difficult to bathe in cold water during the winter, right?

  2. I've toyed with this idea, Dwane, but never quite had the guts to go all the way! My husband (who does the laundry) washes everything in cold, and we've discovered we can solar heat water for showers. Our dishwasher apparently needs hot water to operate correctly; that's the reason I'm still too chicken to try just shutting the thing down. Drat that dishwasher!
    -- MM