I am involved in heating sales.One of the cheapest heating improvements is insulation.Mr Heater sells a ceiling hung infrared that is propane or natural gas that will handle 500 to 600 square ft and is the price range of $349.00.The key to infrared is it heats objects and not spaces.So it is heating you,the car,etc.On balance if you spending less with heating you end up correcting that intermediate step and end up buying what you really need anyways.So insulate and buy a heater to do the job.Face it,what you don't spend on insulation,you spend on payments for fuel.