Diesel heaters

Hey guys…

I picked up a fiberglass truck topper and a 8kw diesel heater with the intention of using it to sleep in while camping in cold weather. Keeping the setup functional yet temporary is the goal. I want to keep the heater outside and duct the heat inside, likely through one of the side sliding windows.

Does anyone have any tips, tricks or ideas on how I can route that 3” heat duct through a 14” tall sliding window and still keep a relatively weather-proof seal? Im thinking about trying to make an adaptor I can pop in the window track that might have a male adaptor I can hose clamp the duct onto? Thoughts?