Are hot-water circulation systems worth the cost?

Two callers phoned Chelan County PUD’s Conservation Department in the last month to ask about installing equipment to help hot water get to their taps sooner. This is a fairly common problem: Water heaters are so far away from bathrooms and kitchens that customers have to let water run through their plumbing for a long time before it’s hot. That wastes water and energy, and tests one’s patience.

Mark Wiser, conservation program manager, referred customers to several Web sites that address this problem (see links below). One solution is installing equipment to circulate hot water. You’ll spend more on energy but less on water. The bottom line, Wiser says, is that “hot water recirculation will add additional costs which include pump operation, heat loss from pipes, extra insulation of pipes, and the equipment itself. It will save on water, since customers don’t run the water system as long to get to temperature, and is more convenient.”

One thing that isn’t mentioned in the Web articles is heat transfer from pipes. If the pipes are kept hot, Wiser notes, they will transfer heat into the house. The loss of hot water then needs to be replaced, causing the heater to run more. In the winter, this reduces the heating requirements of the home slightly, but in the summer this adds to the cooling requirements.

Here’s an article that discusses hot water recirculation systems: http://energyexperts.org/EnergySolutionsDatabase/ResourceDetail.aspx?id=4019

Frequently Asked Questions: http://www.grundfos.com/Web/HomeUs.nsf/Webopslag/76D6ABACA35052D986256AEE00555E40

Energy waste in hot water recirculation systems: http://www.builditsolar.com/Projects/Conservation/Recirc/RecircEnergy.htm

Inefficiencies common in many hot water circulators: http://www.redytemp.com/efficient_hot_water_circulation.html