[font=Tahoma, Verdana, Arial, sans-serif]FYI. I used the below [/font][font=Tahoma, Verdana, Arial, sans-serif]tool to determine [/font][font=Tahoma, Verdana, Arial, sans-serif] heat transfer for calculating insulation requirements of my new build[/font][font=Tahoma, Verdana, Arial, sans-serif]. The post build test: I placed[/font][font=Tahoma, Verdana, Arial, sans-serif] an electric [/font][font=Tahoma, Verdana, Arial, sans-serif]heater that was 415 watts in my new DIY camper and determined through t[/font][font=Tahoma, Verdana, Arial, sans-serif]he [/font][font=Tahoma, Verdana, Arial, sans-serif] tool that the combination of my known ([/font][font=Tahoma, Verdana, Arial, sans-serif]surface[/font][font=Tahoma, Verdana, Arial, sans-serif] area, [/font][font=Tahoma, Verdana, Arial, sans-serif] R[/font][font=Tahoma, Verdana, Arial, sans-serif]-Factor, [/font][font=Tahoma, Verdana, Arial, sans-serif] heater BTU [/font][font=Tahoma, Verdana, Arial, sans-serif]and outside temp[/font][font=Tahoma, Verdana, Arial, sans-serif]erature) [/font][font=Tahoma, Verdana, Arial, sans-serif] should level out at around[/font][font=Tahoma, Verdana, Arial, sans-serif] 55 deg F with 17 deg F ambient (calculated), it actually levele[/font][font=Tahoma, Verdana, Arial, sans-serif]d out at[/font][font=Tahoma, Verdana, Arial, sans-serif] [/font][font=Tahoma, Verdana, Arial, sans-serif]53[/font][font=Tahoma, Verdana, Arial, sans-serif] deg F (actual) allowing several hours for everything to stabilize[/font][font=Tahoma, Verdana, Arial, sans-serif]. I generated a composite R-[/font][font=Tahoma, Verdana, Arial, sans-serif]factor by combining R-factors for wall and floor [/font][font=Tahoma, Verdana, Arial, sans-serif]panels, windows, door material and[/font][font=Tahoma, Verdana, Arial, sans-serif] studs, all by the [/font][font=Tahoma, Verdana, Arial, sans-serif]ratio [/font][font=Tahoma, Verdana, Arial, sans-serif] of [/font][font=Tahoma, Verdana, Arial, sans-serif]surface areas and R-factors for each. [/font][font=Tahoma, Verdana, Arial, sans-serif]Belie[/font][font=Tahoma, Verdana, Arial, sans-serif]ve it or not, pine [/font][font=Tahoma, Verdana, Arial, sans-serif]studs are 40% of your[/font][font=Tahoma, Verdana, Arial, sans-serif] losses on 2" foam walls, I use 10% of total surface area for 16" centers. Maybe you can use this to calculate your heating or cooling requirements Vs trial and error. This listed [/font][font=Tahoma, Verdana, Arial, sans-serif]address is the tool: [/font][font=Tahoma, Verdana, Arial, sans-serif]https://rimstar.org/renewnrg/heat_transfer_loss_calculations.htm[/font][/SIZE]