i'm not sure how big your unit is ... personally I'm not an expert ... But , I do own two buddy heaters . I have a little buddy heater that is about 9,000 btu on the high setting . It works fine , but , it has no thermostat . My trailer is 24ft and on high its plenty , actually , more than enough . What we do is , set it on low about 4000 btu , if it's really cold , it's not enough - but we set the campers thermostat to whatever temp we want to maintain , and let the two do their things . Our experience has been that the trailers built in heater uses a bunch of propane , eats battery power and is very loud ... so our goal is to use it as little as possible . The way I have described , will keep the temp pretty good and make it so you dont have to constantly mess with the little buddy , turning it up and down ( annoying ) .
2 IMPORTANT THINGS TO REMEMBER
1 . THE BUDDY HEATER DOES HAVE A SAFETY SCREEN OVER THE FRONT OF IT . IT'S FINE FOR BIG THINGS SMALL THINGS CAN GET IN ... FABRIC MAY STICK TO IT ... BE CAREFUL WHERE YOU PUT IT ... IT CAN ( WILL ) CAUSE FIRE IF YOU'RE NOT CAREFUL !
2. MAKE SURE THAT YOUR CO/PROPANE DETECTOR IS WORKING ... we have had no issues with leaks or co ... but if we do ... we want to live to tell about it .
I said I have two buddy heaters ... we don't use the big one in the trailer , it;s too much .
One more thing , the buddy heaters are designed to be used with the little 1lb propane cylinders ... there is an accessory hose and filter you can get that will allow you to connect it to a larger tank . That's what we do .