Calor gas heaters give off carbon dioxide and water vapour. No portable gas heater would produce carbon monoxide. That would be insane and murderous. Carbon dioxide is not poisonous. Provided that your house is adequately ventilated, then you don't n...
I don't think space heaters are safe, there could be serious danger from fire or carbon monoxide. Also, as a landlord, you could be opening yourself up to all kinds of liability issues. Be very careful with this!
Baseboard heaters are a little more efficient, but use space heaters in the meantime. Don't hesitate to contact your property manager or owner to take care of the heating. Remember that heat rises, so it use a ceiling fan if you have it, or place a f...