Hi- I just framed a 14X20 4 season porch with 8 ft ceilings and 10 5x2 windows and 2 3' exterior doors. One of the 20 ft walls attaches to the rear of the house- porch is suspended apprx 30" above ground with open air circulating underneath. I have been looking into heating options and have been getting feedback from heating experts that running baseboard heat (i have in hot water baseboard in rest of house) out there will definitely freeze up on coldest days (10 degrees)(i have oil burning furnace) I have been reading about hydronic floor systems and propane wall units. I am looking to obviously get the most efficient system at the best price-- Any advice of total install and operating costs of any of the above mentioned or other alternatives would be much appreciated. Not interested in wood, corn, or pellet stoves. Thanks in advance.