It has gotten down to 0F (-17C) outside so far.
Tropical house min was 65F (18C). I moved all my citrus in there for the cold snap.
Citrus house min was 39F (4C) and totally unheated right now, but since it is attached to the tropical house, it is staying surprisingly warm.
It will be about -6F to -9F (-21C to -23C) tonight, so I am eager to see how the citrus house does. I was afraid to let it go unheated while I still had plants out there, so this is the first time I am able to check how it does without the REALLY expensive electric heater.
Tropical house has a blue flame 30,000 BTU gas furnace. I have not even turned it all the way up yet. It is set to 4 (out of 5) at night.
If we get sun during the day, it will hit 80 in the tropical house with the furnace off, but if there is no sun, then 73 with the furnace turned down to 2.
Carolyn