[orton]

I may not be understanding your question in the right context, but if I am, the only way to cool a van in the sun is to have an air conditioner.

Do not agree. My 08 Sprinter had a 3 1/2" x 4 1/2" hole cut in the floor and a Maxxair fan installed on the roof. You obviously can not cool the van below ambient outside temperature with holes in floor and roof. You can keep the van close to the outside ambient temperature with the holes.

I could open the slider door and start to get in the van and I immediately knew I had left the holes closed. Very obvious. The natural draft of heat rising works.

I did it in my Sprinter because I spent some time studying passive solar house design before I built our house and barn. Both have low on wall openable windows and high at the roof peak openable windows. We do not have a normal sheet rock ceiling at 8'. Both buildings have high open ceilings that match the roof pitch. In the house the high windows are electrically powered. You can sit at the low on wall window and it feels like there is a electric fan pushing air into the house. Air goes in the window and out the open windows at the roof peak. In the barn I use a ladder to open the windows in the Spring and they stay open until late fall.

So with the house and barn as an example I could not see why it would not work in a van. It works. Not as well as in the house because you do not have as much elevation change that is available in a house to create the draft. But it is immediately apparent if you leave the van in the sun and forget to open the holes. Actually works better in winter because you have a source of cooler air.

 

[Chance]

Do not agree. My 08 Sprinter had a 3 1/2" x 4 1/2" hole cut in the floor and a Maxxair fan installed on the roof. You obviously can not cool the van below ambient outside temperature with holes in floor and roof. You can keep the van close to the outside ambient temperature with the holes.

...cut....

I don't understand why you disagree and agree at same time.:s

To me that's not cooling, it's simply keeping it from getting much warmer than the outdoor temperature. You can do the same by opening doors and windows and letting outside air keep van near ambient. You are preventing the van from becoming a greenhouse, but that's not cooling IMHO. Keep in mind the context of the question was to add insulation to cool the van parked in the sun.

When it's 95 F outside (or much higher), it's going to get uncomfortable without an AC. Period. No amount of insulation, holes in floor, or open windows/doors will help keep occupants "cool".

 

[orton]

I don't understand why you disagree and agree at same time.:s

To me that's not cooling, it's simply keeping it from getting much warmer than the outdoor temperature. You can do the same by opening doors and windows and letting outside air keep van near ambient. You are preventing the van from becoming a greenhouse, but that's not cooling IMHO. Keep in mind the context of the question was to add insulation to cool the van parked in the sun.

When it's 95 F outside (or much higher), it's going to get uncomfortable without an AC. Period. No amount of insulation, holes in floor, or open windows/doors will help keep occupants "cool".

Depends on the meaning of cooling.

1. Air conditioning is required to "cool" the van below the outside
temperature.
2. The hole in the floor and in the roof will "cool" the van down close to the outside temperature.

Opening doors and windows does help. Not exactly what you would want to do in a Costco lot while you are shopping.

Sorry to upset you.

 

[Chance]

Depends on the meaning of cooling.

1. Air conditioning is required to "cool" the van below the outside
temperature.
2. The hole in the floor and in the roof will "cool" the van down close to the outside temperature.

Opening doors and windows does help. Not exactly what you would want to do in a Costco lot while you are shopping.

Sorry to upset you.

Orton, we are good. I'm not upset -- I just don't like pointless arguing, particularly when it's about semantics. I know engineers by nature want to be precise but I'm not to that extreme.

Getting back to insulation question, more is not always helpful. I can think of one real-world case where adding insulation to a van that is parked in the sun will make it hotter inside. In my opinion it's not always about more is better. That's all I was trying to communicate.

 

[orton]

Orton, we are good. I'm not upset -- I just don't like pointless arguing, particularly when it's about semantics. I know engineers by nature want to be precise but I'm not to that extreme.

Getting back to insulation question, more is not always helpful. I can think of one real-world case where adding insulation to a van that is parked in the sun will make it hotter inside. In my opinion it's not always about more is better. That's all I was trying to communicate.

The only reason I commented was to suggest something that works in the right conditions for the original poster. Thought it was useful information. Should have worded the reply less aggressive.

From experience, I know an excellent way of bypassing my insulation. In the Sprinter, I bolted the 80/20 aluminum extrusions directly to the steel body. The aluminum inside the van would be the same temperature of the steel body. Van was very well insulated but it did not have much value when a large aluminum structure is inside the van at the wrong temperature. I had read before I built the Sprinter that any conductor inside van should be thermally isolated from the exterior van body. Did not follow that advice due to stupidity. All 80/20 in the Transit will be thermally isolated.

The other change I will try is to minimize the volume that requires heating. I will have a similar cross van rear bed platform as I had in the Sprinter. I will install removable insulated curtains on each side of bed platform from the 30" platform elevation up to the ceiling. A small sleeping enclosure. Might retain some of the heating pad provided heat in the enclosure. Should be interesting to see if the experiment works.

 

[mactweek]

I have no plan to have a rear A.C. in van. I just want to minimize the solar heat effects of a dark color on the interior. We have used a fantastic fan on our previous class b coach house and it worked very well. Having a vent under the vehicle would allow for cross ventilation. I would definitely use a heavy duty screen on it as we have had mice get in through invisible holes in our old van. We also had to evict squirrels and even a porcupine from outside the vehicle. The porcupine had crawled onto a shelf I had put in for batteries and was chewing on the wiring. It was directly under the bed and sounded like it was inside.
Orton I like your idea of insulated curtains around the sleeping area. Windows do convect a lot of cold air into the interior.

 

[cargovanconversion]

My experience over the couple of years with regard to insulation is that for every type of application, there are people that can scientifically explain that it is the best solution and the worst at the same time.

Now I'm facing my own conversion and I'm still not sure what to use.Despite the many negative comments I find about batting in a van, it still looks to me as the best solution. I've had a converted Dodge B-250 for almost 25 years, with batting still intact, no inside rust, no sagging. It also is a good noise barrier.

So what to do?

Van Williams

 

[perchancetodream]

My experience over the couple of years with regard to insulation is that for every type of application, there are people that can scientifically explain that it is the best solution and the worst at the same time....Despite the many negative comments I find about batting in a van, it still looks to me as the best solution...So what to do?

I think you're on the right track. None of the van insulation discussions I've read are based on actual measurement and observation. Everyone is extrapolating from building science without actually doing the science. Best strategy for dealing with moisture seems to be limiting water vapor intrusion and providing a way for things to dry out. 1/8" plywood with latex paint would slow vapor diffusion outward on cold camping nights, yet allow drying to the van interior when the sun shines on the van exterior during the day. Reflectex would get in the way of this process IMHO, as would the stock polypropylene panels. Caulking all holes and joints between the plywood panels and other materials would limit bulk air leaks moving moisture into the batt space. Polyester batts over 1/2" flexible closed cell foam fully adhered to the van main panels under the batts would control vibration, reduce condensation and slow heat transfer in either direction.

 

[Hein]

We offer 3M Thinsulate SM 600L which is engineered for vehicles.
Please reply with a PM and we will send a sample.

http://solutions.3m.com/wps/portal/...ic-Insulation-SM600L?N=4607+3294483010&rt=rud

http://solutions.3m.com/wps/portal/3M/en_EU/Automotive-OEM/-/Technologies/Thinsulate/
(Click on applications tab to see where it's used in vehicles)

 

[Chance]

My experience over the couple of years with regard to insulation is that for every type of application, there are people that can scientifically explain that it is the best solution and the worst at the same time.

Now I'm facing my own conversion and I'm still not sure what to use.Despite the many negative comments I find about batting in a van, it still looks to me as the best solution. I've had a converted Dodge B-250 for almost 25 years, with batting still intact, no inside rust, no sagging. It also is a good noise barrier.

So what to do?

Van Williams

Scientifically best and worst at same time? I would personally guess that the more a person knows about any subject the more they see shades of gray instead of it being black and white. If there was one best product for each application there wouldn't be so many options out there, right?

Besides, in a case like this there are way too many design compromises to be purely about science when determining which product is best. Cost, for example, isn't about science. What about weight as it affects the van? Sure, we can agree light is better than heavy, but where do you draw the line? Then there are other issues like durability, safety in crash, ease of vehicle repair after crash damages van, fire-related dangers, and so on.

I think we need to manage expectations when looking for the "right" solution. In today's world where we can Google anything in less than a second to find an answer, we need to remember that not everything has just one right answer.

The title of this thread itself is interesting -- "For those of us who are not engineers". I'd bet that engineers here disagree a lot, and those who have extensive experience with insulation and heat transfer disagree even more.




P.S. -- If you have something that has worked perfectly for you for 25 years, and is also cheap, safe, easy to install, etc..., then I agree, why change? Do what works for you. Unfortunately not everyone lives in warm climates or use their campers in similar weather and conditions.

 

[tthrsn]

I think that I am going to insulate like a reefer van with spray foam insulation in most locations. The goal is to be able to deal with Canadian winters and to maximize the effect of the Ford rear air conditioning for hot locations. Cost, modification and repairs, out gassing, and drying will be issues.

 

[orton]

I think that I am going to insulate like a reefer van with spray foam insulation in most locations. The goal is to be able to deal with Canadian winters and to maximize the effect of the Ford rear air conditioning for hot locations. Cost, modification and repairs, out gassing, and drying will be issues.

Another issue would be the potential of warping the van sheet metal. Saw pictures of a Sprinter with serious ripples in the bodywork due to the spray foam insulation process. Be sure to use a qualified vendor with experience and a good insurance policy. Done right the spray foam is an excellent choice.

 

[PeterR]

Another issue would be the potential of warping the van sheet metal. Saw pictures of a Sprinter with serious ripples in the bodywork due to the spray foam insulation process. Be sure to use a qualified vendor with experience and a good insurance policy. Done right the spray foam is an excellent choice.

I think that I am going to insulate like a reefer van with spray foam insulation in most locations. The goal is to be able to deal with Canadian winters and to maximize the effect of the Ford rear air conditioning for hot locations. Cost, modification and repairs, out gassing, and drying will be issues.

Ditto to orton on distortion issues, vendor insurance, warranty, and so forth.

In addition to out-gassing, other environmental issues would include using fire-retardant foam, fumes released during a fire, ability of foam to withstand contact with hot roof and sidewalls , which will probably get well over a few hundred degrees Fahrenheit if the van is dark (and there is no air circulation on interior side of the van's sheet metal, by definition). Will there be additional off-gassing issues? Mechanical separation issues due to dissimilar materials expanding and shrinking from during the hot to cold cycle?

What is the plan for finishing/covering the interior of the spray foam? This is a huge issue in residential construction in terms of thickness-control, and the uniformity of the surface if left exposed. Also, how durable is the surface to abrasion and puncture if left exposed?

The apparent simplicity of "just" spraying in foam into a small space may be deceiving, in my opinion.

 

[tthrsn]

Another issue would be the potential of warping the van sheet metal. Saw pictures of a Sprinter with serious ripples in the bodywork due to the spray foam insulation process. Be sure to use a qualified vendor with experience and a good insurance policy. Done right the spray foam is an excellent choice.

I have an upfitter who does reefers and they have developed a technique (taping where the ribs meet the skin to prevent foam from getting between the ribs and the skin and causing ripples) to minimize the problem. I have seen one of their Sprinter reefers and couldn't see any ripples. They feel that the slightly thicker skin of the Transit will further reduce this problem.

 

[tthrsn]

What is the plan for finishing/covering the interior of the spray foam? This is a huge issue in residential construction in terms of thickness-control, and the uniformity of the surface if left exposed. Also, how durable is the surface to abrasion and puncture if left exposed?

The upfitter has a couple plastic or plastic coated plywood panels that they use. Sorry, I don't have the trade names handy. I haven't calculated weights yet but they are pretty thin panels and I will probably order a Transit 350 to help with general weight issues.

Their spray foam guy manages to produce a smooth surface by levelling the foam at the correct time (producing a smoothed but still skinned surface). I spent a few days researching foams and, as far as I can tell, he uses the most appropriate foam available (high r value, closed cell, minimal outgassing, high flame retardation, durable etc.). Again I don't have the trade name handy.

I have the info bookmarked on my home computer but I haven't moved everything to the cloud yet.

 

[unclebob]

Where is your upfitter located? Have you gotten a cost estimate for the foam?

 

[tthrsn]

Where is your upfitter located? Have you gotten a cost estimate for the foam?

The are called Malley Industries and are located in Moncton, New Brunswick, Canada. They do ambulances, service trucks etc. but they will also do small jobs like mine.

For framing the interior, partition with a door, insulation, panelling, ceiling, floor, core electrical (auto battery to house batteries to inverter/charger to fuse panel), core plumbing (tanks and connections), vents, and Espar heater the quote was about CAD$20000. I will probably install the cabinets, bed, sink, toilet etc. Maybe I'll even use 20-80.

Sorry I don't remember the cost of just the foam.

 

[Chance]

Another issue would be the potential of warping the van sheet metal. Saw pictures of a Sprinter with serious ripples in the bodywork due to the spray foam insulation process. Be sure to use a qualified vendor with experience and a good insurance policy. Done right the spray foam is an excellent choice.

Can you post pictures of damage here? Links to Sprinter forum or similar don't always work for me unless I first join. Also, have you heard anything about whether spray foam caused corrosion of van body?

I like many of the features of foam. It's the material used commonly to make insulated sandwich panels for industry and for much of RV construction. It makes for a very strong/stiff-to-weight wall or ceiling. In industry I never ran across corrosion concerns, but some mentions in DIY forums.

 

[tthrsn]

I like many of the features of foam.

One of the things that I liked is that when I went inside the Sprinter reefer and shut the door it was dead quiet. The shop noises vanished. When I had someone yell outside the van door, the shout was just a whisper.

 

[orton]

Can you post pictures of damage here? Links to Sprinter forum or similar don't always work for me unless I first join. Also, have you heard anything about whether spray foam caused corrosion of van body?

I like many of the features of foam. It's the material used commonly to make insulated sandwich panels for industry and for much of RV construction. It makes for a very strong/stiff-to-weight wall or ceiling. In industry I never ran across corrosion concerns, but some mentions in DIY forums.

I can not find the post that showed a black van with damages side walls due to the spray foam. Very noticeable in the picture as I recall. Just need to use someone that has experience. It is a risk.

Do not know if there are any corrosion issues.

Probably the best way to insulate if you avoid the panel damage issue. I will probably insulate Transit as I did the Sprinter. Stuff rigid insulation into wall openings and then fill the gaps with spray can foam. Very time consuming and not as good as a spray job. Ceiling is relatively easy to do with rigid and spray cans. Walls are much more difficult.