Which kiln should I buy and Use? Please Help me.? I am in Rented apartment. Last winter I used electric heaters contained...

I am in Rented apartment. Last winter I used electric heaters contained by rooms and paid huge electric bills. I simply want to plan for the comming winter and want to have any apposite option for heat rooms. A friend of mine has suggested me for unflued ventless gas furnace which can be used without primary alterations as I am not allowed to create a hole in the wall or so. I dont know much something like heaters and also being surrounded by rental apartment I dont know whether I may be able to install gas space heater. I need some expert advices from adjectives members whi know much roughly speaking heating option. Thanks in credit, Regards
Answers:    Well with it mortal a rental you probably won't be able to use a gas stove. Have you put plastic over windows?? If not start in attendance. If you still have the electric heaters still use them. But one and only use them in the room you are surrounded by. If you are in the living room singular have the space heater on in in that, bedroom etc.. No need to steam the rooms you are not using.