Unvented heaters

[Howard Skaggs <flowers@ptinet.net>]

I'd appreciate hearing from those who have experience using unvented
heaters for supplemental or emergency heat in greenhouses. I recently
purchased a 21x48 "parking lot" style greenhouse manufactured by Poly-Tex
which I will use to sell spring bedding. The greenhouse has slide-side
ventilation so air intake is not a problem. I'm in the process of building
hard endwalls, and will put passive ventilators (small ones) near the peaks.

Since this is Montana, we have cool temperatures during the bedding season
and I'd like to have something for heat, especially at night. If the air
intake is adequate and the combustion gases can be vented through the top
is there still a concern about crop damage from CO, ethylene,  or S02, or
will I get C02 and water.

I appreciate any advice.

Howard & Ruth Skaggs
Howard's Flowers
P.O. Box 5342
Kalispell, MT 59903
406-752-1110
<flowers@ptinet.net>