Thank you for publishing Leigh Marymor's article "Hot-Water Circulation" (12/10). It addresses a couple of my pet peeves: first, waiting for hot water to get to the tap; and second, the myth that a continuously circulating hot-water system saves energy. It seems that a circulating system can only save water, and - depending on the system - you will trade off energy use for time saved. With on-demand systems, you still have a slug of hot water left in the pipes after the tap is closed, just as you would in a noncirculating system. The energy it took to heat that water is wasted as it cools. In all cases, the shorter you make your hot water runs and the more you insulate them, the better.

I've insulated the water heater and all the accessible hot-water pipes in every house I've lived in. Insulating the pipes made a very noticeable difference; even 40 minutes after running hot water, if you used the tap again the water flowing from it was still warm - often warm enough that you didn't need to wait for "hot" water to...

or Register to read the full article.