Flippac + Espar/Webasto size ?

[trevpiee]

Been reading a lot about the d2 vs d4 heater sizing. Most people are recommending the d2 for their vw and sprinters. Insulation for a flippac is limited to the rainfly being thrown over. I'm thinking of going with the larger d4 for this reason. Anyone have any experience with an espar/webasto in their flippac? Use will be limited to 20F+. thanks

 

[Arclight]

For reference, a 3,800 BTU Mr. Buddy Heater will just barely maintain the Flippac at 45F when it's 15F outside. That's with the rainfly installed.

Arclight