Greenhouse heaters

[Stefanie]

I am finally getting around to getting an estimate to run a natural gas line to my two greenhouses.. one is 10x20 glass attached to the house, and the other is 8x14 twin wall poly free standing.

I think it's going to cost a fortune just to get the line run, so I'm trying to be slightly economical about the heaters themselves (the point is to not have it cost a fortune each month to heat the greenhouses!). A friend, who also grows orchids, has ProCom brand.. these are vent free 99% blue flame heaters, and he says he has no problems with bud blast. The only thing I don't like about them, is that they have no real thermostat... apparently they are adjustable, but for example, night and day differentiation must be done manually.

They are also nice because they are relatively small, and my greenhouses are small. My other choice is Empire, but they are huge and will require venting, as well as reconfiguration of the greenhouse wall...

anyone out there using ProCom heaters to heat their greenhouse, and if so, what's your opinion? thanks