Regardless of what you use or fit in your van/poptop/motorhome,Please take care and make sure nothing can catch fire.Reading the home page today shows just how dangerous fire is.
Of necessity most of our rigs, whatever we have are built from some very flammable stuff.
So please think about what you have for heating and how you use it.
I've used the following in three of my M/homes, and find it very effective. The 2 kg. gas bottles are available. At the camping stores, one can buy a small gas heater that screws on the top. I have one in my Mazda T 3500, and it saves me a lot in c/park electricity bill, and marvellous on a bush camp. However, the smaller the M/H, the more care should be taken. This heater sits up on the engine cover, and I make sure there is nothing near it that may catch fire. I never have it on when going to bed. First thing in the morning, while the kettle, also on gas, boils. I am not an alarmist, but I also have three fire extinguishers.