Remember, you can always try "Thinking Outside of the Box". If your city dwelling has no heat for the long term, why not build one of these right in your living room?

You can use ANYTHING available for insulation.

Another option is to invite as many people over as will fit in a room, and have a big party. All that animal body heat will make it as warm as a barn full of cattle. It may even become so sweltering you will have to open a window.