If you call a rental place that rents propane tanks and heaters they can sell you a pigtail ( that's what they called it) so you can connect 2 or 3 small tanks together. I just got one last week for $32 and I hooked 3 20lb tanks together and it has ran my tube heater all week no problem. Tanks are out side and its been -15c here at night. Propane price delivered was $1.21 last week. Propane in a 20lb bottle has not gone up for some reason 70 cents a litre. Mr. Heater sells one that will do 2 tanks. F273737