Home Depot doesn’t sell the replacement part - contact the manufacturer.
I would not recommend it. They tip over easily in the wind, causing the glass tube to break.
It’s for propane.
Nope, not hard at all!!
One heater can run n high for about 10 hours on a full tank of propane.
I would say abot 3+ feet
No, conversion is not advised. There are natural gas heaters similar to this though.