adding a heat strip

I was considering installing the heat strips in our two duo therms, they say they are prewired for them. I saw them for 53.00 apiece and thought why not try it out. Our MH is sitting in the driveway empty of LP till they fill our house tank up, most likely next month and like to go out there once in a while to have quiet time and watch a little Clint Eastwood shoot up the bad guys. I do wonder about 2 @ 5600 btu's doing a whole lot