John McGaw wrote:
BryanL wrote:
I'm planning to purchase a steam shower for my master bathoom and
have been doing some serious research, but I'm still hesitating
between a 110V unit and 220V unit. The 110V is certainly more
convenient, but it's not ETL or UL certified. THe 220V is ETL
certified but I heard that it's very costly to run. What shall i do?


The cost to run the devices depends on how much power they use, not
what voltage they run on so Watts is the value to compare. And don't
forget that the efficiency of the device in turning water into steam
will make a huge difference in how you will use and enjoy using it -
a unit which uses little power can, by definition, make less steam
(assuming that they are both designed for optimum performance). The
power does not depend on the voltage -- you can develop 3000W from
either voltage, it just becomes less practical to obtain higher power
from the low voltage source with 3600W being the practical upper
limit. Will you enjoy a "steam shower" as much if you need to turn it
on an hour before using it and find that it never gets more than
tepid inside? An underpowered unit could well do that for you.

Personally, I'd go for something in the high-power end of the range
whether it be 120V or 240V since it is not likely that it will be used
all that many hours a month. Find out exactly how much your utility
charges for power. Then do the math for various power levels and you
will know how much every minute will cost you and you can then make a
rational decision.

Let me add that the total power/cost of operation per minute of use is
based, as you note, by the watts. Assuming the unit does not cycle on and
off during use, then the total watts can be computed by multiplying the amps
by the volts. A 10 amp 240 volt unit will provide the same heat as a 20 amp
120 volt unit.

Note a 240 unit will be very slightly more efficient overall, but not
enough to bother with.

--
Joseph Meehan

Dia 's Muire duit