Hi J: I took the liberty of e-mailing you info on a direct-vent space heater called Ecotherm. I believe it will be easier to install than breaking into your central system. They are available in 5,600, 8,400 & 14,000btu models, both natural gas and propane. These units use outside air for combustion, and exhaust outside also. If anyone needs info, please e-mail me or call 800 851 9891. Happy new year everyone, from Brian at Hot or Not Inc.