New Texas Entrant Into Class B Market

[PinIN]

That's why i email them an asked. If they used new tech they say so and say it loudly, instead they say it's R32 and radiant barrier, not we used vip's or aerogel. If the third party supplier says it R50, the builder can advertise it R50.

[Davydd]

Originally Posted by PinIN

That's why i email them an asked. If they used new tech they say so and say it loudly, instead they say it's R32 and radiant barrier, not we used vip's or aerogel. If the third party supplier says it R50, the builder can advertise it R50.

They can advertise it sure but that doesn't make it so. Simplest solution is ask them for an independent certified testing laboratory report substantiating their claim. If they can't, refuse or claim proprietary, then beware. They don't really know.

Seriously, it is simple physics. Mojoman mentioned Aerogel at R-10 per inch. That is probably the most advanced development. That's still 3+ inches of uniform insulation! to get that rating. No way are they doing that anywhere in that B. But if anyone wants to believe it, remember PT Barnum.

A radiant barrier does not translate to a high R-rating. That is a plus though much like comparing white to black in heat buildup.

I had no trouble keeping our Advanced RV cool for our cat when gone most of a day with air conditioning running and tested in 95 degree Palm Springs weather. I haven't encountered many air conditioning opportunities because we actively avoid them in our travels. Conversely, I overheated my ARV last week and got it up to 98 degrees with about a 20 degree day just using a 1500w electric ceramic cube instead of our built-in Espar and Rixsen glycol heat transfer capabilities. We camped a full week in temperatures always below freezing night and day down to 0 overnight comfortably while boondocking. So you can insulate a B effectively. I know Roadtrek doesn't or they haven't said so. I've opened up my former Great West Van Sprinter and the fiberglass batt insulation was there but loose and not thorough and I don't know if it was installed behind the cabinets, doors and other non-reachable areas. The cab areas while driving in all three of my Sprinters were comfortable in cooling and heating. We have electric heated seats now. I didn't request them. They just came as part of an upgraded Sprinter package of some other things I wanted. But they're nice.

[avanti]

Just for fun, I looked up what is theoretically possible wrt insulation.
According to this source, 1 inch of hard vacuum can get you to about R30. As of 2013, the article says that Dow Corning was planning to bring an R30 vacuum panel to market at a projected cost of $10-12 per sq ft. (that should be within ARV's price range)

But, it turns out that you can do even better. Even in a vacuum, you can get heat transfer via infrared radiation. But, according to this, you can reduce the thermal conductance by half by filling the vacuum with photonic crystals (whatever they are).

So, R32 in a van isn't QUITE impossible, at least along uninterrupted surfaces. The problem, of course, that the shell of a van isn't even close to being an uninterrupted surface, what with glass and metal structural members everywhere. That's the real trouble with these claimed insulation values--there is a big difference between using insulation at a given rated value and actually achieving that value in real life. I agree that the chances of ever netting anything like R32 in a van is slim to none.

[SiennaGuy]

Originally Posted by Davydd

I know Roadtrek doesn't or they haven't said so

Roadtrek RVs have all sorts of high-tech equipment available to generate energy. It still baffles me why they don't lower the energy needs of their products with a very low-tech solution: insulation.

[BBQ]

Originally Posted by SiennaGuy

Roadtrek RVs have all sorts of high-tech equipment available to generate energy. It still baffles me why they don't lower the energy needs of their products with a very low-tech solution: insulation.

Because you cannot see insulation,
so most of the manufacturer just put the cheapest stuff in there and close it up.

Out of sight, out of care.

[InterBlog]

Originally Posted by Davydd

...I've opened up my former Great West Van Sprinter and the fiberglass batt insulation was there but loose and not thorough and I don't know if it was installed behind the cabinets, doors and other non-reachable areas. The cab areas while driving in all three of my Sprinters were comfortable in cooling and heating. ...

The cab ceiling of our Sprinter Class B (2007 Airstream Interstate) was not insulated, which we discovered upon removing the liner. We added Dynamat plus a layer of radiant barrier on top of that, and it made a huge difference in cab comfort.

We know that there is Pink Panther behind certain interior areas, but we haven't determined how extensive it is. I've heard anecdotal reports of Interstates not being insulated behind the wet bath, which turns it into an inferno in hot weather. I've yet to check that on ours.

[mojoman]

The bat Aerogel is a little over R10 per inch in other configurations it is rated at up to r30 so theoreticaly they could achieve R32, but it would cost a fortune. I have a small jar of Aerogel pieces, $50 for about a quart of it. Full unbroken sheets are very expensive. They use the broken pieces, granules in-between sheets of glass to super insulate. I plan on making a insulated vent cover with the stuff.
BTW, they use Aerogel in the C7 Corvette.

[mojoman]

FYI, to use to insulate fully insulate an average class b would add $2k or more (buying it by the roll) to the price which is not really that much for a high end class B to triple the R rating and take up less space and weight.

[cruising7388]

Originally Posted by Davydd

A radiant barrier does not translate to a high R-rating. That is a plus though much like comparing white to black in heat buildup.

With respect to insulation values, isn't the current rage to demand these coaches in designer colors like charcoal, bronze, black etc, sort of shooting ourselves in the foot?

[Davydd]

Originally Posted by cruising7388

With respect to insulation values, isn't the current rage to demand these coaches in designer colors like charcoal, bronze, black etc, sort of shooting ourselves in the foot?

It depends. My B is dark grey yet I have numerous times mentioned real performance in all weather conditions that shows I have more than adequate insulation and more than any other major converter. So, I am not shooting myself in the foot. Anyway it may not be all that critical because I am not hearing complaints about it from dark grey Roadtrek owners. I've had white and I have had silver as well. There didn't seem to be any indications of heating or AC problems. Maybe an overblown worry?

BTW, my B is 100% covered, floor, walls, doors, wheel wells, ceiling and cab area against the metal body with Hushmat, which is about an 1/8" thick rubberized material with a reflective foil face. It does wonders in being a conductive barrier as well as a super sound deadener.

[mojoman]

Darkcolors can absorb 70 to 90 percent of the sun’s radiant energy, light-colored paint can help reflect the sun’s heat away. White for example, will gain 35 percent less heat than black, according to the solar folks. I have reversible window shades for the windshield and door windows, in the winter, with the black side out, they actually warm the interior.
If you mostly visit cold places, buy a dark RV.

[booster]

Originally Posted by mojoman

Darkcolors can absorb 70 to 90 percent of the sun’s radiant energy, light-colored paint can help reflect the sun’s heat away. White for example, will gain 35 percent less heat than black, according to the solar folks. I have reversible window shades for the windshield and door windows, in the winter, with the black side out, they actually warm the interior.
If you mostly visit cold places, buy a dark RV.

But the black color will also radiate more heat to the surroundings at night, so where is the crossover point? I have no idea, but I think a bright chrome van might be the most heat stable

[mojoman]

People buy dark colored RV's because they look cool. People buy white RV's because they are cooler.

[booster]

Originally Posted by mojoman

People buy dark colored RV's because they look cool. People buy white RV's because they are cooler.

What about the ones that buy the bright red?

[avanti]

Originally Posted by booster

What about the ones that buy the bright red?

"If you can't make it good, make it BIG. If you can't make it BIG, make it RED!"
— Paul Rand

[eric1514]

Originally Posted by booster

What about the ones that buy the bright red?

Hey, I practically stole that thing.

Eric

[Marley]

Afaik the outside colour generally only means anything if there is light involved. In daytime the paint colour will determine the absorption of heat and the material below (steel for Class B's) will affect the rate of thermal transfer. Night time the material will transfer at the same rate as day - that is where the insulating layer comes into play - slowing down the rate of thermal transfer.

We (the closest town to us) have a whole subdivision of homes that have solar liquid heating panels all tied into a system that takes daytime heat off of rooftops and stores in underground tanks to be used at night to heat the homes when required. Interesting experiment into alternate energy and thermal mass etc.

[booster]

Originally Posted by Marley

Afaik the outside colour generally only means anything if there is light involved. In daytime the paint colour will determine the absorption of heat and the material below (steel for Class B's) will affect the rate of thermal transfer. Night time the material will transfer at the same rate as day - that is where the insulating layer comes into play - slowing down the rate of thermal transfer.

We (the closest town to us) have a whole subdivision of homes that have solar liquid heating panels all tied into a system that takes daytime heat off of rooftops and stores in underground tanks to be used at night to heat the homes when required. Interesting experiment into alternate energy and thermal mass etc.

All bodies radiate energy all the time base on temperature. The color you see is either generated by the temperature, like an electric coil going from black to read, or from reflectance. At night, all the energy is in the non visible spectrum. That is why you will get frost on the top of a car but not the sides. The top is radiating heat into space, while the sides are radiating to the side, and whatever is there is radiating similar heat back.

Visible light is only a part of radiated energy, that is why infrared filters can cut heat way down, but let visible light through.

Most of the hot water storage systems like you describe will shut off the water flow at night, so they don't actually cool the water by losing heat by radiating it to the sky.

[cruising7388]

Originally Posted by Davydd

It depends. My B is dark grey yet I have numerous times mentioned real performance in all weather conditions that shows I have more than adequate insulation and more than any other major converter. So, I am not shooting myself in the foot. Anyway it may not be all that critical because I am not hearing complaints about it from dark grey Roadtrek owners. I've had white and I have had silver as well. There didn't seem to be any indications of heating or AC problems. Maybe an overblown worry?

It's funny that you consider the absence of cooling complaints from RT owners with darker colors as good evidence that there may be nothing to complain about, while concomitantly, you're loath to give Avion the benefit of the doubt despite the absence of any combination waste tank complaints from Azur owners. (BTW, for the record,I have no relationship of any kind with Avion)

But, I digress.....

Sure, it could be an overblown worry. But it could also be that the consequences of dark colors are not immediately visible with respect to creature comfort. While some air conditioners may be up to handling the inevitable increased interior heat from dark exteriors, perhaps not all of them. I don't know what BTU rating your AC is but I notice that the AC ratings on class Bs are less than the classical 15k BTU units - some 13k and even some 11k units.

Also, I think the less obvious consequence of darker coach colors may not cooling capacity, per se, but the increased AC duty cycle required to maintain the desired interior temperature. This may be of relatively little importance if the AC is being powered from shoreside or a generator, but if you're off the grid and running the AC from lithium batteries, the increased duty cycle will invariably reduce the period that the lithium batteries and inverter can support the AC without requiring the startup of the second alternator or the Onan generator.

I fought the good fight for white and lost the battle between form and function, so our RT is charcoal. The 11k AC seems to keep up although how it fares in desert heat remains to be seen. The good news? It looks elegant. The bad news? 10 minutes after washing it, it looks dirty again.

[InterBlog]

Originally Posted by cruising7388

With respect to insulation values, isn't the current rage to demand these coaches in designer colors like charcoal, bronze, black etc, sort of shooting ourselves in the foot?

This question and some of the replies approach the underlying issue, which is, it's not a question of the ambient outdoor temperature - it's primarily the incident energy that we have to worry about. And that is largely dependent on sun angle. An 85 degree day in Minnesota (46.7 degrees north latitude) does not equal an 85 degree day on the upper Texas coast (29.8 degrees north latitude). I'd be willing to pay the $2K for the high-tech insulation because I've had to deal with the ramifications of living at the lower latitude. In fact, it might go on my long-term list as a DIY project.

There is no way that I would ever buy a Class B that was any color other than white or silver. Even with ours being silver, it has tinted windows the full length of each side, and the windows were black-masked by Airstream. It looks wonderful but it's a terrible heat sink. I've had to create a two-layer shroud that I can place down the entire length for those days when one side or the other is getting blasted with intense sun. It attaches with tiny neodymium magnets and folds up into something the size of a large ham sandwich for transport.

Light-weight reflective fabrics can be very expensive and you can see that I used a cheap one here (tension irregularities are visible in the fabric). I wasn't going for showmanship on this one, just effectiveness (blog post here for sewing instructions). And it does help reduce the heat gain considerably, because if the incident energy can be prevented from accumulating on the outside, then there's less work for the insulation to do to prevent that energy from migrating to the inside. (The reflective mask on the windshield and cab side windows is a stock item; I got it from one of the Sprinter aftermarket sellers.)