Does anyone have any experience with ductless splits for very low inside temperatures (3 degrees C)?
We have a church in the Ottawa Ontario area (zone 6A). The church is only occupied for about 1 hour a week. We are using a very old oil fired FA furnace.(about 80% eff. 164K BTU input). I did some measurements last winter when the outside temperature was -20C. The furnace ran for about 5 minutes each hour to maintain 3 C inside. Would I be able to use a ductless split to maintain the inside temperature during the week and use the oil fired system to bring the temperature up for Sunday morning?