Heating an unfinished basement?

Im looking to heat an unfinished basement, about 1000sq ft, bare concrete floors and concrete walls. i know i need a propane vent free heater but.. do I want to buy a radiant heater or something else? id like it to be about 70-72 degrees 24/7, how much propane am I going to need for this? I know nothing about heating, i lived in my old apartment for close to 20 yrs and my heat was included.