northlander fish houses?

i am thinking about getting a base station fish house. i am looking at either a clam 5600, or the sleeper, although i am not seeing a lot of sleepers around (do they even still make them?) and then i came across the northlander with the insulated skin. anyone know how any of these heat? i used to have an otter lodge and it was a “cold” house in my eyes at least compaired to my old 4×8 with wood floor. weight isnt a real issue being i have snowmobiles and a trailer although i did find that the sleeper weighs in at 200 pounds where the 8×8 northlander weighs in at only 150

northlanders are made by canvas craft

The clam sleeper is now the 6800. The floor design on the 6800 is a little better than the sleeper was but it is basically the same. I had a clam sleeper and I loved it. I have now down sized to the 5600 due to the sleeper being stolen