Hi Rumble,

http://europe.hbc.honeywell.com/prod...6uk07r1006.pdf

Thanks very much, that eluded me. It still doesn't give the power
consumption though.

Back of a fag packet calcs suggest about £1.50 in electricity for the
closed season, so an FCU would pay for itself in about 3 years.

This is based on an assumption that it uses 4 watts of power for six
months I think. Might it not use more?

Well worth it, no?

Hmmmm, better than my fag-packet calculations for my loft insulation,
and not such a dusty job ;-)