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Good Questions: D'MAND Hot Water System?

8-25-dmand.jpgHello AT,

One of the features of the much-debated Margarido House is the D'MAND hot water system. It's basically a water pump that circulates or flushes your hot water line when you need hot water. The water that was in the hot water line is then pushed back into the hot water furnace to be reheated. This saves the water that would have gone down the sewer if you just let the water run until it is hot. In my house the second bathroom can have a wait of 3 minutes in the morning for the water to be hot, so that's quite a bit of water. I'm interested to know if anyone has firsthand experience with this device.

Thanks!

-Edgar

 
 

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Image: The MetlundĀ® Hot Water D'MANDĀ® System

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Comments (12)

We installed one in May and have really fallen in love with it. It was a minimal cost and we think it saves quite a bit of water since you no longer have to wait for the shower or sink to warm up

posted by stacy on August 25th 2008 at 2:56pm
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http://www.chilipepperapp.com/Default.htm

Great question. I've been looking at the above product that does the same thing.

posted by JenPDX on August 25th 2008 at 3:12pm
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I have one on my water heater. When I had it set incorrectly a few months ago, it took 5 minutes for hot water to get to my shower. When set properly, I can get in the shower and THEN turn the water on and not get hit with cold water. It's fantastic. No wasting water waiting for it to get hot!

posted by LilyC on August 25th 2008 at 3:14pm
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thanks for the positive comments and the additional/similar product to look into.

one more question, is there any problem with turning on the cold water while the pump is running?

posted by eec007 on August 25th 2008 at 3:31pm
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one more question, is there any problem with turning on the cold water while the pump is running?

No. Hot and cold water run in separate pipes. I was looking at the install diagram. You're only hooking the pump up to the hot-water line that supplies the faucet.

Maybe I'll quit procrastinating and buy one!

posted by JenPDX on August 25th 2008 at 6:26pm
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I just learned about these and have heard great things. I have been told that they are becoming pretty standard in Europe.

posted by eakdesign on August 25th 2008 at 6:32pm
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They used a similar product on This Old House.

posted by chaseunchase on August 25th 2008 at 9:35pm
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excuse me if this is a 'stupid' question but...does this only work with faucets with two separate handles?

posted by Enamorada on August 26th 2008 at 4:35am
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the ask-this-old-house episode mentioned above was a good illustration of install and use. the only thing that seemed clumsy was the doorbell-style switch on the sink.

digging into the chili-pepper site site linked above scare me a bit if only because of this......

the hot water lobster looks like a simpler, non-electrical option...

posted by redneckmodern on August 26th 2008 at 4:52am
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Just saw these at Costco and wondered--thanks for the info.

posted by jen_g on August 26th 2008 at 8:29am
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Okay, the geek that I am...

1. Cold Water Tap - I kinda now suspect that if you turn on the cold-water tap, you might get tepid water coming out after the pump has been on. So there isn't a problem with the cold water if you turn it on but you might get tepid water?

2. /i/does this only work with faucets with two separate handles?

No. A single faucet handle has a valve/control thingy inside the faucet that blends the hot/cold. But the hot/cold water plumbing still comes in two separate lines. You're hooking up this mechanism to the two separate lines.

posted by JenPDX on August 26th 2008 at 12:31pm
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So... has anyone used the hot water lobster that redneckmodern mentioned?

posted by laura in la on August 26th 2008 at 8:28pm
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