On Fri, 30 Oct 2009 00:19:56 +0000 (GMT), "Dave Liquorice"
wrote:

Each kg of gas burnt produces a kg of water. But a kg of gas yields
quite a bit of energy. 10kW springs or there abouts springs to mind
so a fire running at a couple of kWhr output isn't a great generator
of moisture, a cup full/hour ish.

Thanks. I've not got or used a butane heater, so my remarks about
condensation were based on what I had read. I thought that some old
posts here had said you needed to run them with the windows open to
provide the necessary ventilation to prevent condensation and
incomplete combustion, and if the window was open it defeated the
point of having a heater on. Perhaps concerns about condensation have
been exaggerated?

Fan heaters don't work during a power cut... That is why we have a
portable gas fire.

I was wondering about getting a gas fire for power cuts and I suppose
that's what started me reading up about this. However, I don't know if
we have power cuts often enough to justify this. But I thought that
the preferred method in this group was to hook the boiler up to a
generator or inverter?

Thanks.