"cjra" wrote:
Hmmm, I wonder if the systems in the US are not as good as those in the
UK? I never had any problems there, and most people I knew had that
system.

Based on my limited experiences in England, the standards are different on the
European side of the pond. Americans expect to be able to nearly drown in
their showers, while the Brits seem to be happy if water comes out of the shower
heads at all :-) . Not too many tankless units being sold that can give the
short-term flow rate of a 50 gallon tanked unit.

IMHO, there are a lot of undersized units being sold in the US, mainly because
units that put out enough flow to make the typical American happy cost some
serious $$$.

So, we are upgrading all gas and plumbing lines now anyway (house is
totally being renovated). It's not worth it to just do the tankless
now? Since all the lines are being changed?

Do it now. In addition to the upsized gas line, you'll probably have to run a
much larger exhaust vent than the previous water heater required. Just don't
scrimp on the water heater. I have a Takagi TK-2, and wouldn't mind a unit
with a bit more flow. Even then, I still much prefer it to the water heater it
replaced.