Should be safe to send azolla long before June, I realized my post looked like I was saying June.
Anyway, I use an electric heater, it does suck up electricity. Lights suck up a lot of electricity which is one reason I don't have any yet. I am having a humidity problem in there as well. I don't have a fan running. I guess I need one.
Panels blew out in the storm in Dec and the heater was running running running. We had huge bills. I have a lot of tropical plants in there and must heat it. I keep them in there year 'round, not just in winter.