-- Last Updated: Feb-06-13 10:58 AM EST --
....... 30,000 btu with oxygen depletion safty cut-off sensor , automatic thermostat control or 5 heat levels , automatic electronic pilot (usually battery operated) ... should be enough to get her warmed up . Some models have a fan ...
Do you have open rafters or flat cieling ?
Nephew uses two 20 lb. LP bottles , has them valved at a T , left on or right on . It's easier to deal with two 20 lb. bottles and they are more readily available at many local places for swap out than a single 40 lb. bottle .