X2 on about 10 hrs. Any more and your gonna want to have a spare bottle ready. The propane units are great, they just require a little more tending than the electric units, the burners tend to go out in wind so you can't venture too far away from them. Its much better to retro fit them for a 20Lb BBQ tank if possible. Temp control is a little more difficult also because they are pretty much Hi/Low, once you get used to them there is a "grey area" in the gas valve to fine tune them. I love mine for the lake. Just not a set it and forget it kind of unit.
My 2 cents