In message , Ramon A
writes
Harold, This was my original thread - Thanks for the input. May I explore
your comment further. Are you saying that for the general use of a gas
heater to keep frost at bay in wintertime, and with a thermostatic control
on the heater then Venting for safety reasons should not be a worry -
assuming that i do not stay in the green house with the heater on and the
door shut - of course???

That depends. Without adequate ventilation and a gas or paraffin burner
you will get a gradual increase of CO2 and when things start getting
critical CO, carbon monoxide building up to dangerous levels. The CO
will potentially kill you stealthily without you noticing. Usually
greenhouses are draughty enough that this isn't such a major risk.
Houses are another matter - there are still far too many fatalities from
dodgy gas burners.

Some plants are also rather intolerant of CO. If you are intent on
taking the risk at least fit a CO alarm so that you don't end up walking
into a trap. I would not even consider using gas or paraffin heaters
without adequate ventilation. Even with ventilation condensation is
always a problem.

Thermostatically controlled electric fan heating is probably cheaper in
a small greenhouse anyway.

Regards,
Martin Brown

regards Ramon



8-))////////////////////////////you might suffocate if you have the heater
on 24 hours per day and you sleep in the greenhouse........I am still
alive
and never vented when using my propane heater......and, as David Hill
said,
carbon dioxide is a benefit. Large commercial greenhouses owners spend
big
money on a carbon dioxide generating system.

Harold W.




--
Martin Brown