Mark, that is exactly what I want to know. if you are right, then I
should be able to put a small, single room, in-line unit before my hot
water heater, and during peak hot water usage, still have enough hot
water for everyone to take showers. I wonder how much more in
electricity this type of set up will run me?

Mark Sparge wrote:
wrote:
My concern is that my current tank water heater will let through, lets
just say for argument sake, 10gpm, and by putting an inline in front of
it, the inline will only let through, say, 3gpm, thus my whole hot
water system will be throttled back to 3gpm. I want to know if small
inlines are limited to a certain flow, or if the flow rating is just a
number that guarentees full heating if the flow is not higher.

snip.
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The way I understand it -- and I might be wrong so I'm open to comment
-- is that an tankless unit has a rated flowrate that indicates its
maximum efficiency. IOW, it might be rated at 3gpm, but will actually
allow 10gpm to pass through it -- just not as hot.

I THINK I know what I'm trying to say here -- hope it makes sense to
someone else.

Mark