On Fri, 27 Nov 2020 19:17:42 +0000, Robert
wrote:

[snip]

If you consistently only need 200/300 watts per hour then a cheap
option would be to just use a couple low power ceramic heat "lamps"
rated at 100 watts each and forget about a thermostat. The amount saved
in capital would pay go along way towards offsetting any excess power
being used.

That's around the wattage I need at the moment, but it will vary with
the outside temperature so I don't think a fixed wattage solution will
work.

Of course you then dont have a nice DIY project to keep you busy !!

That's true - I find the journey just as interesting as the
destination. Thankfully my wife doesn't read usenet!