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Old 06-16-2017, 06:56 AM   #3
JRTJH
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Join Date: Mar 2011
Location: Gaylord
Posts: 26,836
Rick52 has touched on the biggest consideration about air conditioning in RV's. That's energy use and insulation. Going to Lowes.com and looking at window air conditioners, an 8000 BTU unit is rated to cool 350 square feet of space and a 15000 BTU unit is rated to cool 850 square feet of space. Even with slides, the biggest RV's are less than 500 square feet and most 30 to 35 foot RV's are around 300 square feet of floor space. Even with 30,000 BTU's of capacity, many RV's are "hot inside when in the sun". It's "difficult to understand" why such a small space doesn't cool well until you consider that the walls are R-9 and the ceiling/floor are typically not much more insulated than that. Then consider that the "roof A/C ducting" runs directly under the 3/8" roof membrane/decking (with virtually no insulation on that R4 foam ductwork which is being bombarded with the sun's heat, and the roof is often too hot to touch or to walk on with bare feet with that ductwork "less than 1" under it. It's a miracle that we get any cooling at all. With 2" wall construction, 5" roof construction and 1" slide construction, single pane windows that are "overly large to give a sense of bigger interior space, you can only get so much "heat resistance".

Should we be able to cool better? It would be wonderful, and how we position the RV (shade, big walls not facing east or west, etc) makes a significant difference, as does the color of the RV. But if you could imagine putting a window unit air conditioner in one end of a 8x20 vinyl tent pavilion, blowing into the space, imagine the BTU's it would take to make that dark green tent feel comfortable.... I wonder if the A/C in that tent would cycle off/on much differently than our RV? ie: run almost continuously. RV's are better insulated than that tent, but when compared to a "S&B" structure, not by much.

I don't think we'll ever see an "energy star" rating on an RV. It's just the nature of a "temporary house" that is so "under-insulated and uses so much energy to try to make it comfortable"....

When you get right down to "brass tacks", the "carbon footprint" for one of our RV's isn't that much "less impressive" than the "carbon footprint" from Al Gore's private jet.
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2015 F250 6.7l 4x4
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