I agree completely with Chris's post. Rather than "pumping in more heat" why
don't you look for ways to minimise the losses by reducing draughts and
looking at ways of improving the insulation qualities of your greenhouse?
Failing that you are down to looking at the total energy costs for different
fuel types for your particular situation. This should then at least point
you in the right direction,
regards,

David

"Chris Hogg" wrote in message
...
On Thu, 10 Feb 2005 18:49:45 GMT, "keith ;-\)"
wrote:

I have a 10x 8 greenhouse which I grow orchids ,I need to keep the
greenhouse to 15c/59f min 24/7.So need to find out the most cost
effective
way (energy wise) to do this.I am currently using a 2 kw greenhouse
heater
which is to expensive to run,so I have to rethink what I could use?
I know tubular heaters are quite cheap to run but don't know if they will
keep the greenhouse to the min needed in the coldest of winters.
I have seen a Colorado 2kw fan heater which says ,this unit`s cost and
efficiency savings come over time with a low power consumption of 30
watts.It costs £169.00 so don't want to buy it if it doesn't do the job &
isn't much cheaper to run for my situation,do any of you use this fan!
I am interested to know how others heat there greenhouses & costs to
maintain!

The heat loss from your g/h will be the same whatever the heat source.
So an electric heater will use the same amount of power whatever its
design, assuming it's properly thermostated. The idea that tubular
heaters are cheap to run relative to other electric heaters is
therefore false. They'll use whatever power is needed to maintain the
temperature. How the heck a 2kW fan heater can claim to be only using
30 watts is beyond me. Try heating your g/h with a 30 watt electric
light bulb and your orchids won't last long, even with it on all the
time. The 30 watts is probably just for the fan alone.

I think I'd seriously investigate fuel-burning heaters, but subject to
all the caveats expressed in the earlier thread.



--
Chris

E-mail: christopher[dot]hogg[at]virgin[dot]net