On mine, I had a nipple put between the tank and the drain, and plumbed
the return line into that. Yes, it will mean a little extra work when
the heater has to be replaced. I save a lot of water because the supply
line across the basement is 3/4 inch, and around here the water rates
have gone up far more that gas or electricity. I insulated the supply
line and left the return uninsulated, and it works well without a pump,
but I have a lot of vertical line to the upstairs bathroom where the
crossover is, and I'm sure that helps.

Its true that there is some heat loss, but where I live we have far more
heating than cooling days, so I just consider it a radiator. Installing
a check valve will prevent any back flow.

Bob wrote:
This is my first visit to this group, so the question may be a repeat.
I am thinking about installing a return pipe on my hot water feed to the
kitchen to reduce the amount of cold water that is wasted before the hot
water has reached the sink.
Where is the best place to make the connection close to the hot water
tank? It takes nearly four litres of cold water to run through the pipes
before the hot water arrives. I have lots of pipe and connections left
over from different projects and I might as well use them for this. My
ceiling is easy to access. My problem is knowing where to connect near
the tank.
I have also read that some people have installed a "U" near the tank to
reduce the loss of heat when hot water is not being drawn for use.
Anyone have any details about this idea?
Many thanks for your ideas.

Bob