No space for an eco drain so......

[J.P.M.]

I concur with JPM's comments: Plus if you are trying to preheat potable water you may have to consider a dual walled heat exchanger. A leak in a single walled exchanger could cause cross contamination of the potable water. Shower water will contain fecal coliform bacteria, do you want to drink that? Typically, gray water is going to contain hair, soap scum and dirt, so how do you prevent those from entering and plugging the heat exchanger? If the water is on the hard side, minerals may also build up on the inside of the exchanger.

There will be condensate on the outer piping that will drip, how do you catch that condensate and dispose of that water?. Building air heat exchangers typically have a hose that drains to a janitors floor sink in a commercial structure.

I have designed and installed dual walled heat exchangers on boiler systems, they are costly. Stainless steel, pressure certification by mechanical engineers.

All part of the hassle. There's lot's more of a technical nature. Not worth the time/$$/hassle and above all health/safety issues.

[C_Heath]

good stuff thanks guys!

[citabria]

I concur with JPM's comments: Plus if you are trying to preheat potable water you may have to consider a dual walled heat exchanger. A leak in a single walled exchanger could cause cross contamination of the potable water. Shower water will contain fecal coliform bacteria, do you want to drink that? Typically, gray water is going to contain hair, soap scum and dirt, so how do you prevent those from entering and plugging the heat exchanger? If the water is on the hard side, minerals may also build up on the inside of the exchanger.

There will be condensate on the outer piping that will drip, how do you catch that condensate and dispose of that water?. Building air heat exchangers typically have a hose that drains to a janitors floor sink in a commercial structure.

I have designed and installed dual walled heat exchangers on boiler systems, they are costly. Stainless steel, pressure certification by mechanical engineers.

[J.P.M.]

If the water is entering the building at 49 F.on its way to the tank, any heat it picks up will be from the dwelling, or the air in the dwelling. Eventually, it'll get to your water heater and get more heat. You pay for at least some of the space heat that heated the water on the way to the tank, and the energy to heat the water once it got to the tank. As a practical matter, and If you're all electric, it makes little difference whether you insulate an incoming water line or not. I'd save the money and skip it for now. You've got bigger fish to fry.

Skip the heat exchanger. They are nowhere as efficient as ads will claim, they will need maintenance, and most are poorly constructed. All are overpriced. If you practice water and energy conservation, there will be less usage of water, hot and cold, and therefore less leaving the dwelling and less heat to recover making any cost effectiveness for a greywater heat exchanger even less. Like most all of this utility bill reduction business, the cheapest and best way to save money is to not use, or minimize use up front. That's the pay you money, take your choice reality of it.

If you DIY a heat exchanger, you can't build a good one and keep it maintained and bacteria free with even a remote chance of getting near safe in terms of health concern, practical or cost effective. I designed heat exchangers for a living and I can't do it either, but I know I can't and I know why.

If you want to save as much energy as possible, and water as well, minimize your hot water use and insulate the tank more. Then get low flow shower heads and faucets. Wash stuff in cold water. Take (SHORT) showers instead of baths. One trick: leave the drain closed in the shower while using it and let the water cool off, giving its heat up to the dwelling. you'll save as much energy as if you put that water through a heat exchanger and the cost will be zero. The no free lunch part: The tub/stall will probably need a bit more frequent cleaning. But, something to think about: a greywater heat exchanger would get just as fouled or more but probably won't get cleaned as often.

All this stuff and more is readily available in the open literature. NOMB, and suit yourself, but when I was new to all this in the mid'70's, as you claim you are now, I got a few books on energy conservation/retrofits,etc. and educated myself. Some stuff worked, some stuff didn't, but it was all in a few places and was there for the discovery and a good source of ideas.

[C_Heath]

Addendum: already have pipe insulation on the hot water line. It was a big help in the wait at the shower head for hot water. 3 to 1 in time

[C_Heath]

I did look at the eco drain or perhaps building some sort of grey water heat exchanger but the way my shower is, it would be in the center of the basement at my entry doors. So with that, I noticed that my incoming water line was 49 degrees and steadily warmed up as it got closer to the tank. Keep in mind, #1 I'm new to all this energy conservation stuff, #2 house still has copper water lines, #3 just trying to do what I can to lessen my footprint and save money at the same time. So, wouldn't it be better as a second option to at least spend $12 on some insulation and get that water temp up as it ENTERS the water heater so it won't have to work so hard? Or wil this cause some sort of negative reaction?

Thanks
newbie