I think you will find that it generates plenty of heat. How well your hut is insulated will determine how long it retains the heat for. Some huts are going to be 3 season huts. To be 4 season, they will need to be well insulated.
We have come across the Chilli Billie from Chilli Penguin stoves - but with a hut of reasonable size we're now concerned it might not heat the space sufficiently and in a sustained way with a 2.5-3kw output. The next ones up are 5Kw and we're pretty sure this would be too much! - So we're looking for any experiences of these to get some reviews from hutter users of the chilli billie particularly...