I need to know about makes and models and how they have worked for you.
I don't
know much about flow rates so please give a description about how heavy
the use.
I have a drilled well so my water is quite cold. Tia lucy

The need for a 5" vent vs the traditional 3" vent prevents many people
from getting one. Other than that, there are already plenty of
previous posts (mostly positive) for you to search through.

On 2005-11-02, wrote:

The need for a 5" vent vs the traditional 3" vent prevents many
people from getting one. Other than that, there are already plenty
of previous posts (mostly positive) for you to search through.

Only the passively vented models use a 5" vent. Of course, with an
actively vented model you need to supply electricity, and you have no
hot water in a power failure.

The other common "gotcha" is the need to run a larger gas pipe because
of the very high BTU/hr demand of these units. I'm planning to put
one in rated at 200K BTU/hr, and I need to run a 1" gas pipe to it
because it is farther than 30' from my gas meter.

Cheers, Wayne