*PLUMBERSSTOCK EXPERT* responded:
I'm sorry I do not have enough information to even come close to answering your question. This unit only offers 45,000 BTU heating. I need to know the number of doors, garage doors, windows, and insulation. You have basically 625 square feet 10 feet high and if the ceiling is insulated and the walls are insulated and it has a few windows and a few doors. You can contact our Customer Service professionals who could have the heat loss calculation completed but my guess is that you will need at least 75,000 BTU. For further inquiries, please contact one of our customer service representatives at 435-868-4020 between 7:00 AM and 7:00 PM MST or email them at firstname.lastname@example.org.