In article , "Paul" wrote:
Can someone refresh my memory as to why 240V electric baseboard heaters are
"more efficient" than 120V?

They're *not* more energy-efficient. A 240V heater will produce more heat than
a 120V heater of the same physical size, but it will consume proportionately
more power as well.

In my application I am looking at install one
750W electric baseboard in a bathroom, on a dedicated 20A 120V circuit, but
the heating man strongly suggests I use a 240V model. Problem is the
breaker box is completely full, and I'd have to run a subpanel just for this
circuit if we go 240V.

IMO, running a new 240V circuit to power a single 750W heater is nuts. 750W at
120V is 6.25A, well within the capacity of a 15A 120V circuit.

My other concern was GFCI protection - at 120V I could install a GFCI
breaker in the panel to protect this heater circuit

You could even install a GFCI outlet in the bathroom, and feed the heater from
that.

do they even make
240V GFCI's for the panel (GE)?

Yes, but they're pricy.

I am a little bit worried about someone
splashing water from the sink or a toilet overflow going into the electric
baseboard heater -- the baseboard will be within inches of each.

GFCI sounds like a good idea, then. You might check local code to see if it
even permits placement of an electric heater that close to fixtures.

Last item - electric "hydronic" baseboard sounds better than the standard
electric baseboards - more even temperature - but I also saw a website say
the hydronic units were "safer" - why? because the heating element is
enclosed in a fluid tube and not exposed?

Yes.

--
Regards,
Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt.
And who wants to leave buttprints in the sands of time?