Replies

1. 
   Joe_Hennessey | Sep 11, 2001 12:28am | #1

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   No. I've seen such advertised, but looks like magnetic fuel mileage smoke and mirrors to me. All those sources you named are in separate parts of the house. How many of these heat exchangers are you going to have? That will all see 5 minutes use at a time once a day or twice a week? Payback is gonna be a looooooooong way off. Joe H

1. 
   rmanbike | Sep 11, 2001 02:48am | #2

   *Find you a old baseboard radiator and circulate through it in the winter time. YMHO, Roger

1. 
   Steve_Wright | Sep 11, 2001 09:28pm | #3

   *Terry,I'm not sure about commercial devices that use waste water for supplemental heating. Just for discussion though, assume you have 100 gal of hot water (120 degF) per day going down the tubes. Relative to 70 degF, you have about 34k BTUs to play with. Though not trivial, it isn't a great amount either. With heat exchange losses, your down even further (50%?). Then you only use the system during the heating season. As Joe said, the payback could be very long.That said, I believe payback is more than recouping dollars spent for the system, since conservation doesn't have a distinct price tag.You might want to check this out:http://oikos.com/esb/49/gfx.htmlIt is a heat exchanger (~$200) to pre warm the hot side of fixtures, and thus is used all year. Could even build one yourself if so inclined.Good luck!Steve

1. 
   David_Thomas | Sep 13, 2001 02:24am | #4

   *Here's another link about the same unit:http://www.endlessshower.com/welcome.htmThis would work best if you designed your house around it with all the fixtures close to the HX and HWH. And have a floor below those fixture in which to install the HX. Knowing a bit about HX's, I have a lot of trouble believing the claimed 60% heat recovery. 30% would be more like it.That could make sense over a several year time frame, if you do the installation yourself and enjoy that kind of work (i.e. don't debit yourself for the sweat equity). Especially if you heat your water with propane or even more so, horrors! with electicity. And/or if your incoming water is quite cold (mine is 40F). Then your hot water costs you more. It also gives you effectively more hot water capacity because the recharge rate is better with warmer incoming water. The easiest way to recover heat from the shower and bath, is to leave the water in the bathtub, drain closed, until it cools. It will transfer most all of its heat (plus humidity) to the air. Both of which are desirable during the heating season. -David

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   Jim_Roberts | Sep 14, 2001 01:14am | #5

   *I fully agree with this responce. I wouldn't hesitate at all to use one of these GFX heat recovery units if your plumbing components are in reasonable proximity to take advantage of it. They are simple, easy to install and have no maintenence costs. Now days, $180-200 is a small price to pay for anything in a new home. The efficiency would not have to be very high to allow a very reasonable payback time.

2. 
   Art_B. | Sep 14, 2001 07:48pm | #6

   *It may not be code ( was very careful about having no joints inside the exchanger) , but put the supply lines to the HWH inside a 25 ft long 1-1/2 copper drain line in own home. Waste HW from the shower/tub/dishwasher can thus transfer heat to the cold incoming water. Water to water heat exchangers are among the most efficient. The only cost was 2ea. 1/2" by 1-1/2" by 1-1/2" inch Tees.

2. 
   Terry_K_Vinet | Sep 14, 2001 07:52pm | #7

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   I figure there must be a lot of BTU's going down the drain from my dishwasher, washing machine, showers, etc... Has anyone ever come across a viable method of recapturing this heat to supplement the heating season?