In article ,
"Tom" writes:
I have converted part of a detached garage into a office. The floor,
ceiling and all the walls are well insulated and now I've come to the
problem of choosing a heating source. Due the buildings location a rad from
the CH in house is not possible and i don't want one of those portable gas
bottle fires so i guess my only option is an electric heater. Has anyone
tried one of those oil filled electric radiators? Are they expensive to run
and is 2K powerful enough for a room 3m x 4.5m? Is there anything else on
the market that is suitable?

Without knowing the thermal properties of the insulation, no one
can say. Quick back of an envelope, you'll need 500W of heating
to handle 2 air changes per hour, even if the insulation is 100%
perfect, and more than this if you will want to do a fast warm
up from a cold starting point.

In the summer, I fitted a B&Q air conditioner. I've been playing
with its heating mode in last few days (although it hasn't really
been cold enough). It gives out 3.8kW of heat for 1.3kW power
consumption. If B&Q have any left, it wouldn't surprise me if
they might start going cheap at this time of year. I don't know
how well they might work if it gets cold enough to ice up the
outdoor unit though -- it is doing something which might be a
defrost cycle when it switches off, but I don't know for sure.
It would give you air conditioning in the summer too, of course.

--
Andrew Gabriel