tony.latham wrote:Now, the question is, do I want to switch to XPS for the roof? R 7.5 vs R5.6...
You'll sleep with the windows and vent fan cracked. You'll never notice the difference in R value.
Tony
Of course, that depends on where you camp, and the weather conditions.
I didn't insulate my roof, of 3/4" plywood (thoroughly waterproofed), because I would never need insulation up there in colder weather (I've only camped in 36F minimum temps) and the small inner space of my 4'x8' gets enough heat from the one or two Lasko "My Heat" (200W each) ceramic heaters I'll use, my body heat, and I'll use a winter sleeping bag. Stays OK for me, as I solo camp.
In moderate weather, for N.Texas-S.Okla., in March-early April, I'll use opened awning windows, side vents (with computer case fans sucking outside air in/blowing cabin air out), and/or the 11" fan (Honeywell Turboforce Fan, mounted hanging from the overhead shelf at the front of the trailer. That works ok, unless the pollen and allergens get real bad, then I'll shut the windows, direct the vent fans outward, and use the A/C unit (with filter) to help with cabin cooling, sans the pollen (the A/C recirculates the cabin air, so no extra allergens get introduced). Actually works well.
But, the warmer months require a different approach, as some days I've camped got up to over 100F. With direct sun heating up the trailer all day, I'd depend on my LG 5000 btu window A/C (mounted in the rear wall, between the cabin & galley, behind my head) to cool it down. The A/C unit is placed up high, where the output is first directed along the underside of the hot ceiling, then redirected back towards me by the 11 inch overhead fan. That works OK at night when the sun goes down, but it takes awhile.
The delayed cooling during 100+ days and hot nights was defeated by using a pop-up canopy placed over the whole 4'x8' camper, shielding at least the roof from the direct sun (I lower it as close to the roof as possible). That reduced the heat by a bunch! I use the canopy as a rain shield also (it always rains, at least one T-storm per trip, ever since I camped with the BSA in the '60's), and it overhangs my "front porch" (the door I use to get in & out, my sitting & cooking area, and the entrance to my pop-up potty tent), giving me a 4'x8" area out of the sun or rain. I'll stay cooler and drier outside under the canopy, and the cabin will stay cooler, with the roof shielded from the sun, as well (I have reflective aluminum "silo" paint on all upward facing surfaces...roof, front sloped roof, and raised rear hatch), but the canopy helps more. You might consider using one for warmer weather months, too.
- not the neatest arrangement, but it suits my purpose, arrived at after a decade of different arrangements
- trailer set-up with canopy.jpg (957.27 KiB) Viewed 1620 times