Good Thinking

Inventive heating design delivers instant hot water to every faucet

Inventive heating design deliv...
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October 1, 2006 When we saw the technology behind this inventive line of hot water circulation pumps we just had to give it a mention. Having to wait for hot water at the faucet is inconvenient at best, but this system offers the convenience of having hot water at every faucet in the home instantly and is claimed to save up to 15,000 gallons of water annually for a typical family of four. Offered as both a retrofit and new installation, the system installs under the sink or faucet farthest from the water heater-where hot water has to travel for the longest time.

Laing Thermotech has developed a number of innovative products to solve this problem for homeowners, including the Autocirc1 and Autocirc2 and UltraCirc pumps. Claimed to cost less than 10 cents a day to run, these products can conserve enough energy to pay for themselves in less than two years.

The Autocirc is geared for retrofit applications, while the UltraCirc is designed for new construction. Both systems integrate easily with the existing hot water supply line and can be installed by homeowners or their local plumber.

The Autocirc1 pump installs under the sink or faucet farthest from the water heater-where hot water has to travel for the longest time. A built-in temperature sensor automatically turns the pump on when the water temperature in the hot water supply line cools down to 85 degrees Fahrenheit. The cool water in the hot water supply line is then pumped back into the cold water line and back into the water heater. Hot water will also be instantly available at all other faucets in the supply line between the water heater and the faucet where the Autocirc pump is installed.

The Autocirc2 works in a similar fashion to the Autocirc1, except it has two components: a pump and valve. The Autocirc2 pump is installed at the water heater and controlled by a timer, while the valve is mounted under the sink farthest from the water heater. When the hot water supply line becomes cool, the adjustable thermostatic valve allows the cool water in the hot water supply line to flow into the cold water supply line, replacing it with hot water.

The UltraCirc is a compact recirculation system that includes a timer-controlled pump and several valves. A return line is run from the last tap on the hot water supply line back to the water heater. Hot water is circulated in the supply line and immediately becomes available whenever someone turns on the faucet.

Paul Judd
The only problem with recirculating hot water is that unless insulation of pipes is increased it looses more energy and makes system inefficient. Pipes have more surface area than storage tanks and will cool quicker. You might save some water by not having to run tap to get hot water but will waste much more energy.
Jason Stoddart
So then just add insulation...........
If this system runs all the time, whenever the hot water pipe cools down, then regardless of the insulation on the pipes all it will be doing is cooling the water in the water-heater down all the time....
Saying it pumps the cooled water into the cold pipe, and then back to the tank, really. Have a look at your home plumbing, and tell me if the cold water pipe at any location in your house actually goes to the water heater.... it may, but most won't.
Also pumping cooled hot water into the cold water supply,may not be such a good idea... (contamination concerns...)
If the system were to act on demand (like when you turn on the tap... or when you turn in the bathroom light...), and send the water back through a dedicate line to the water heater, then it may be a good idea...
A Better idea, is to have a thermostatically controlled instant heater (gas would be cheapest) at the shower, or other usage points, where the cool water entering from the pipe can be heated until the hot water comes through (then the less efficient instantaneous heater turns off), then you are saving water and probably not costing a lot more energy than pumping...
Probably another smart idea would be to run the cold water out of the system, whenever you turn on the hot tap ((patent pending )mechanically thermostatically controlled 3-way tap), and send it to a (low pressure header tank used to flush the toilet or washing machine (grey water uses)or water the garden, feed the dog... and only let the water leave the system, when it is hot, sure it means a small wait, but no cold water from the hot tap.... and it saves water and energy...
Hey of course, if the water is being heated by solar, during the day, the hot water system can run on a single loop, through the heater and to every hot water tap in the house, like all solar systems, it will stop running at night, and a one way valve to stop any potential back siphoning during hot water use (may as well get the hottest water from the tank....)
Are we really so impatient, that we can't wait a few seconds for the hot water to arrive.... (course, I hate a cold shower, unless I intend to have one but..)
We had this installed as part of our new house and I can tell you, it\'s the greatest thing since sliced bread! Wouldn\'t go back to the old way for NOTHING!!
To the comment from MD. You said "Are we really so impatient, that we can't wait a few seconds for the hot water to arrive.... (course, I hate a cold shower, unless I intend to have one, but..)"
It is not about being impatient. It is about saving our water. It takes 20 seconds or more to get hot water from my bathroom faucet. Each second uses 8 oz of water, 20 seconds x 8 oz = 160 oz. That is over a gallon of water wasted down the drain. Think of how many people that need water to live that we could help if we could fix our hot water systems to correct all that waste of water down our drains. Also the fact that I pay for my water and could use that money on other things like food and clothing. It's about the fact that it's wasting water and not an impatient problem. Just saying.....