Copper tubing around main waste drain

I was with a friend looking at new homes and saw the strangest thing. The main waste pipe in the basement was PVC at the top and through the floor at the bottom but, the section in the middle was copper pipe with flat copper tubing wrapped around the entire length from top to bottom. The tube appeared to be connected to the water supply system via pex and making the tubing a closed system of some type.
Anyone seen this flat copper tubing around the waste pipe and know what it is???
I did not have my camera with me, so sorry , no picture. Hopefully I described it well enough or is easily recognized by someone out there.


This is to collect heat from the drain waste water.

very nice

Yes and like new house windows save money and the pay back is about 21 years or more for both.


That is it folks. Thanks. It was quite a puzzle.
I wonder if they are really worth it though. Articles indicate that they cost $300 to $1000 dollars to install, depending on how, when and who does it and they take 3 to 10 yrs to get pay back even though they are relatively simple and should last at least 30 years.
At least I will know the next time I see it. There seem to be quick a few being put in by some new home developers. I suspect the low end cost is more applicable when it is done during the building phase.

When was the last time you say a copper stack in a modern home.
Most homes the stack is hidden in the wall and covered .

Like you I don’t feel it is worth the effort .

Fifteen years inspecting and I have never seen one

This is not a copper stack but an added piece.
This says it all!

Yes, Drain Water Heat Recovery (DWHR) System. Came across this a couple of weeks ago on 1 year warranty inspection in Stouffville, ON.

I asked the owner about it, he said that he has noticed some savings but I personally dont think its such a great energy savings option.

That is because your design is wrong for the Home Owner.

Sorry, what do you mean?

I read a test result on those units conducted by the NRC or CMHC and it was reported that they are not worth it…

I am not saying they are worth installing but if you do you must install them just like the picture shows. Closest you can to the the Water Tank and the return to the Water tank. I do not take the authority from CMHC or NRC on this as the studies they do are many times filled with flaws.
The course is an eye opener and if you feel there is not a signifiant difference in trying to heat water from 25 degrees instead of 11 degrees. You need to think about that for awhile.

But only while someone is taking a shower. You need to think about that for a while.:wink:

Or if it is installed correctly every Hot Water use in the Home. Works well for big families but will provide no benefit for those without. Best to have a circulation design for best results overall.

How would that work when taking a bath?

How would a hot water recirculation system help?

How would that help an average family?

You need to think about that for a while longer…:wink:

[quote=“mgratton, post:16, topic:83820”]

How would that work when taking a bath?
Does not work when taking a bath.
How would a hot water recirculation system help?
Reduces the losses of hot water in the supplies.
How would that help an average family?
Approximatly 30% savings.

Thanks for posting…learned something new.

You would need to add all together to get this kind of savings and the calculations are on ROI but most are supported by a government grant to reduce energy in the home.

Really don’t know the point of increasing temp that will eventually get heated by the water tank . but maybe just end up saving around 10% on there gas bill . if not less. The point is when the hot water is drained this copper tubing which the main water supply gets heated up slightly before entering the water tank which in turn does not need to work as hard or better yet waste much gas heating the water up before releasing it up.