On Sat, 24 Feb 2007 13:34:22 +0000, Peter Parry
wrote:

All electric heaters are almost exactly 100% efficient

Not if you consider the efficiency of the overall system (i.e. heat in
you / power in). That's the aspect where the more recent
long-wavelength IR heaters (flat white ceramic plates, no quartz and
definitely no visible glow) have the advantage. Losses in the air are
less at this wavelength, so you receive more of the heat personally.

Although I still wonder about the justification of heating an outdoor
patio. Why not just burn whale oil to keep warm, or get a nice panda
skin coat ?