Community Forums

Mirandazzi · 11-11-2011, 10:46 AM

So, as you all can tell, my husband and I have never owned a fifth wheel before. They are telling me that my 5th wheel has an R value on the roof and floor of 38 and the sidewalls a 7....what does that mean? Are we doomed for the winter?

dsbike · 11-11-2011, 11:02 AM

Your feet & head will be warm????

Midniteoyl · 11-11-2011, 11:28 AM

R38!?? Thats quite thick... R7 is 1.5" of foam board (Actually, its R7.5) that would make your floors and ceiling over 8" thick just in foam..

Garywneel · 11-11-2011, 02:58 PM

What year and type of unit is that you have?

Always-RVing · 11-11-2011, 03:25 PM

We have just been talking about this... Many RV's are horrible with insulation while others are, well,,,, not tooooo bad. I just talked to someone who was installing a dish on the roof of a 5th wheel.. Nice model... They had to cut a small hole in the roof which allowed them to see between the roof and the inside ceiling. What they saw was amazing... A perfectly open space from front to rear between the ceiling and roof. A void of nothing but open space.. Not one ounce of insulation. Nada..

RV manufactures absolutely know RV's need to have optimum insulation from cold and heat. So why? Why did this 5th wheel have nothing in the top?

My Motorhome goes from hot to instant cold (winter) and cold to instant hot (summer) in just a few minutes. In the summer, if you turn off the air, the thing heats up faster than Wilbur's two dogs in heat. In the winter, it will freeze without heat in minutes. Where's the insulation?

RV's should have maximum insulation... Maximum

mhs4771 · 11-11-2011, 06:09 PM

That R38 is a play on words. They will use some foam or fiber glass insulation, then add a foil barrier (similar to the space blankets/emergency blankets) while it does not have any real R value, it will reflect heat back into the unit, so some advertising expert came up with those high R values. This info was gained during a tour of the Keystone Montana plant this past Sept.

RustyJC · 11-11-2011, 06:21 PM

Shown below are typical R values for a full-time 5th wheel.

Rusty

Cat320 · 11-11-2011, 06:46 PM

As noted above, I find the R 38 rating a bit of an exaggeration. My experience is that the R value is not the problem but the slide joints leaking air that causes the most discomfort...really got drafty down there.

RustyJC · 11-11-2011, 07:15 PM

Quote:

Originally Posted by Mirandazzi

They are telling me that my 5th wheel has an R value on the roof and floor of 38 and the sidewalls a 7....

I seriously have to doubt the claims of R-38 for the roof and floor. If the walls are only R-7, why bother, even if R-38 were achievable.

Rusty

Mr_D · 11-11-2011, 07:34 PM

I'm not sure what Newmar's ratings are but it's among the highest. On ours we ordered it with dual pane windows and the optional roof insulation package. The roof is over 6" thick and it's stuffed with foam and batting. Does a really good job too. We didn't order the tank heating pads and I wish we had as we aren't getting to retire and go south as soon as I thought!

bluepill · 11-11-2011, 07:51 PM

Quote:

Originally Posted by Batman_777

RV manufactures absolutely know RV's need to have optimum insulation from cold and heat. So why? Why did this 5th wheel have nothing in the top?

RV's should have maximum insulation... Maximum

I think it's mostly a marketing decision. To get real insulation in the walls would mean taking 10 to 12 inches away from the interior width, the same for the walls of the slides (5-6" on each wall), and a higher floor/lower ceiling in the slides. Since most users stay in temperate climates, the manufacturers don't add the insulation.

TXiceman · 11-12-2011, 11:51 AM

Most of the heat loss is the roof...heat gain also. In the summer the 7.5R wall are not much with the sun on them.

What brand and model are you looking at.

Ken

Always-RVing · 11-15-2011, 08:37 AM

It appears RV's are not under any kind of federal owner minimum requirements. RV's are excempt.

So the manufacture is only obligated by the public's demand, sales and marketing.

I want to mention Mc'Donald's has a new foam cup very light and thin for coffee or hot beverage. I had hot water in a cup that was likely 160-180 degrees. The outside of the cup was barely warm. The new cup is very thin and light, yet insulates. So why isn't this material used for insulation in RV's along with other insulators?