Is this a heater or an air conditioner?

It is a kerosene space heater. The listing also shows cooling capacity, SEER and WiFi/remote lines that do not belong to a kerosene heater, so ignore those when comparing.

How much space will it heat?

The listing gives both 450 square feet and 160 square feet. Realistically, expect it to take the chill off a one- or two-car garage or a workshop, not a whole house.

Does it need electricity?

No. Kerosene heaters run on fuel alone, which is why they suit power outages and off-grid cabins. Battery ignition, if fitted, is the only electrical part.

Can I use it indoors?

Only in a ventilated space. Kerosene produces carbon monoxide and odor, so crack a window or door and never use it in a sealed bedroom.

What do I need to run it?

Kerosene (1-K grade is the cleanest), a funnel, and a wick if it is a wick model. Expect to trim or replace the wick and drain the tank at season's end.

How does it compare with a propane or electric heater?

It gives more radiant heat per unit than a plug-in electric heater and needs no power, but propane is easier to source and electric is odor-free and ventless-safe.