I assume your going gas tankless but consider the following before
gas will require a large new gas line directly to the tankless perhaps
even a new meter and may
require a new flue, all those BTUs have to go somewhere, the install
will be expensive, tankless will require routinue maintence by
qualified techniocians $$$ if the tankless quits working NO HOT WATER
AT ALL, the costs o do all this will exceed the standby losses, the
the tankless warranty and expected life.....
in areas that get cold in the winter low incoming water temperatures
may generate lower output temperature, and chilly showers. unit must
be sized to maximum flow. OPs going to be a large costly unit.
standby losses of regular tanks, foam insulated today are pretty low,
and in the winter the standby losses go to heat your home so they
really arent lost. although in the summer they can add to heat load a
in low flow situations like a faucet open a little to wash your hands
the heater may not trip on and you will have cold hand washes.
when you turn on a hot water faucet the tankless must detect flow, and
turn on burners before you get any hot water. so assume some water and
sewer waste, heck that cost may exceeed the standby losses.
regular tanks are long life dependable appliances and pretty cheap
too. say 500 bucks installed with a 10 year life. 50 bucks per year
cost thats not even a decent candy bar cost per week.
good luck with your tankless although you may be better off with a 75
or 100 gallon high 75.000 BTU tank, it will give you nearly unlimited
hot water without some of the downsides.
UNLIMITED hot water may result in people showering forever increasing
dramatically your water sewer and heating bill. teenagers