I am trying to determine how to size an electric unit heater in a greenhouse, or at least have someone confirm my heater choice. It is in a school on Mass. The room is 17'x25' with a sloped ceiling that averages 16' high. The only glass walls facing the elements are the south side and the roof. The north wall is part of the heated building and so are the east and west walls. I have no idea how to size the heater.
I have a 20 amp, 208 volt, three phase circuit that is available. I have found a couple of unit heater models that put out 17,000 +/- BTUH, 350 CFM that could be put on the available circuit. Will this size be adequate? If not, what would be a better choice?
Thank you in advance for any responses. This is my first post.