When we bought our first camper a big difference in cooling efficiency was ducted vs non-ducted AC and a 15k BTU units. At the time many on the market were NOT ducted. Ducted provides a better distribution of the cold air. Since I am not in the market for a camper I do not know if they are all ducted now but ours works really well with just one 15k AC. In addition; I have installed a hard start capacitor and a digital thermostat which is light years ahead of the analog version. No wide variances in temp before the compressor cycles in and out.
I can attest that that tinfoil bubble insulation that was previously mentioned works! I have a 17' molded fiberglass trailer sitting in full sunlight in 97 degree heat right now, temp inside the RV is 75 and that's not even with the A/C at full blast. I have the stuff up in every window but one (cat needs a window to peer out of) keeps a lot of heat out. I think having upper storage cabinets help too, the sun beats most directly up there and the cabinets get warm inside but act as a buffer for the rest of the trailer.
Becky
If even 'the road less traveled' doesn't work for you, start creating your own
Lessons on the journey to full-time RVing (my blog): Interstellar Orchard
Johnworth914 wrote: What the insulation in the "polar packages" is doing is preventing the COLD AIR from infiltrating to what would be othewise exposed or nearly-exposed piping and holding tanks.
The insulation is designed to keep the INSIDE warm. In the winter, the solar gain is largely offset by the heat migration thru the sidewalls, floor and roof. In the Summer, the solar gain far exceedes the insulation value, efectively trapping the heat inside.
Insulation works both ways. Have you ever put hot coffee in a thermos bottle? It'll keep it hot and then you can put ice tea in the same thermos bottle and it'll keep it cold. The insulation has no idea what it contains it just keeps what ever is in that insulated compartment whether it be hot or cold from dissipating so easily.
Of course insulation works both ways. But your Trailer is not a sealed thermos. The heat gain that brings the inside temp to well over 100 or when it is over 100 outside in the summer can not be overcome by the volume of cooler air coming from the ac unit. The insulation really does you far less good in the summer when you are fighting both the migration of the conditioned air thru the walls AND the heat gain from the sun.
In winter you have the inverse, your insulation and furnace are greatly aided by the solar gain. That's why it is easier to keep your trailer warm during a bright sunny day than it is at night, even though the air temp may be the same.
all tis being said, my point was that the OP was misunderstanding the meaning of the words "polar package" It was not something that would lead to his TT being able to shed the HEAT, it refers to the plumbing insulation package (and sometimes tank heaters) that allow him to use his trailer when it is COLD OUTSIDE.
Alaska is next! Still trying to fit the pontoons to the RV so We can get to Hawaii!
Johnworth914 wrote: all tis being said, my point was that the OP was misunderstanding the meaning of the words "polar package" It was not something that would lead to his TT being able to shed the HEAT, it refers to the plumbing insulation package (and sometimes tank heaters) that allow him to use his trailer when it is COLD OUTSIDE.
Nah, never thought polar meant it'd shed heat, I guess because I mentioned it you thought it. It's merely an enclosed underbelly on mine, nothing more, nothing less. Regardless, I think the next time I RV in 110+ temps I need another AC unit or some shade. You two were entertaining though in your debate....lol.
Johnworth914 wrote: all tis being said, my point was that the OP was misunderstanding the meaning of the words "polar package" It was not something that would lead to his TT being able to shed the HEAT, it refers to the plumbing insulation package (and sometimes tank heaters) that allow him to use his trailer when it is COLD OUTSIDE.
Nah, never thought polar meant it'd shed heat, I guess because I mentioned it you thought it. It's merely an enclosed underbelly on mine, nothing more, nothing less. Regardless, I think the next time I RV in 110+ temps I need another AC unit or some shade. You two were entertaining though in your debate....lol.
Sorry, didn't mean to put words in your mouth. I guess I misunderstood.
Happy camping
Billieg2 wrote: If you want a cheap fix go to home Depot and buy a portable A/C. I got one for my 400 sq. ft.office and it will freeze you out. Less than $400 and you can use a short extension cord and plug it into the 20 amp outlet on the post.
I saw at Sam's Club today they had 12K BTU portable ACs for $299. Very tempting, since 13.5K BTUs, 32 ft, and 2 slides is not a good combo when the temps get over 85 deg and there's not much shade to be found. The R-7 insulation in the ceiling doesn't help. Would only need it during the heat of the day. I added 2 additional AC vents and enlarged the existing ones to improve the airflow. Also, have vent pillows for the vents and cover the skylight with Reflectrix to keep out heat and light.
Heading out tomorrow with temps forecast to be in the upper 80s to mid-90s most of next week. We see how it holds up.
2008 Nissan Titan SE, Crew Cab, 4x4
Long Bed, Big Tow, Roadmaster Active Suspension
In a stick house, R38 attic insulation or higher would be expected in the attic of a reasonably insulated house. Exterior walls would be expected to be at least R11 and likely higher.
How can we expect a TT or 5er of any length with ceiling insulation of R-7 to be cooled by a 13,500 btu AC unit?
R7 is possibly 1.5 inches of fiberglass insulation. If the TT/5er is over a couple of years old, the fiberglass insulation has likely settled or been affected by condensation.
Back in the mid 70's (when I was young and stupid), I purchased a 14x60 mobile home. On a 100+ degree day here in Oklahoma when the 3 ton Central Air would not adequately cool the trailer, I made the decision to install a window unit in the wall of the living room to help cool the living room. After buying a large 24k btu window unit, I went about installing it in the wall. I found 2X2 wall studs and 1 1/2 inches of insulation in the wall. This is the same construction used in aluminum walled/wood studded TT's now. IF I ran both the 36 K Central and the 24 K window unit, I could cool my aluminum barn to around 75 when it was 100 outside. BTW. the attic insulation was r-11.
If you carry these calculations forward to a travel trailer with R-7 roof insulation, and probably r-7 in the walls as well, you will find that a 28 foot RV would need a minimum 16K btu of cooling to match what I had in the mobile home that had the same basic construction.
With the insulation values and temperatures of the OP, he would need at least 2500 additional btu to cool his TT in the conditions quoted just to hold his own. The only things the OP could do to improve his situation is to either add an additional AC unit, buy a new, better insulated TT, or move to cooler temperatures.
One last comment about insulation that is used in TT's. While fiberglass batting style insulation is fine for a house, it does not maintain its effectiveness in the TT environment. It settles, it gets damp from condensation from the living area and without proper venting, it will grow mold. All of these work against the effectiveness of insulation in older TT's with that style insulation. Once it is degraded, it is effective neither at keeping cool/warmth inside the TT against the elements outside.
I've pondered adding additional insulation to my ceiling. It's a 3" trussed roof with 1"x1" aluminum framing. There's basically a 1" gap between the ceiling panel and the insulation and AC duct work. If I pull the staples out of the ceiling panels where they attach to the trusses, I wonder if I can get enough room to slide in pieces of 1" polystyrene insulation? That would about double the R-value in the ceiling.
Exocet wrote: I've pondered adding additional insulation to my ceiling. It's a 3" trussed roof with 1"x1" aluminum framing. There's basically a 1" gap between the ceiling panel and the insulation and AC duct work. If I pull the staples out of the ceiling panels where they attach to the trusses, I wonder if I can get enough room to slide in pieces of 1" polystyrene insulation? That would about double the R-value in the ceiling.
If you end up compressing the existing insulation you will be defeating the purpose.
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