insulation setup, who thought out of the box?

[Haf-E]

I agree that use of Reflectix insulation on windows would be very effective in the cold - even in a roof tent or poptop with fabric.

Part of this is the issue of the use of the "R" value here in North america - the rest of the world tends to use the "U" value instead - which is the inverse of the "R" value. So if the reflectix has a conduction thermal resistance "R" value of 2 (maybe possible but not likely), then the "U" value would be 1/2 or 0.50 - which means that the losses would be halved.

The "U" value is more useful since it provides a direct understanding of the value additional insulation provides - the R value is more "marketable" as its a bigger number and sounds more impressive. Consider the following values

R-value / U value / % / BTU's required to heat

R=2 / U=0.50 / 50% / 6000 BTUs (hypothetically)
R=10 / U=0.10 / 10% / 1200 BTUs
R=20 / U=0.05 / 5% / 600 BTUs
R=50 / U=0.02 / 2% / 240 BTUs

So going from an R-value of 2 (reflectix) to a R-value of 10 (2 inches of foam) results in 1/5 the losses or BTU's required. Adding another R10 - 2 inches of foam - only reduces the losses by 5% more - or requiring 600 watts of heat. Even then adding more to go to R50 - i.e. 6 inches of foam - only saves 360 watts of heat.

So the best bang for the buck is adding any insulation - which is why people probably talk about how adding reflectix insulation made such as difference... because it did cut the losses in half perhaps...

In most vans, the losses through the single pane windows would dominate the losses if the walls had any level of insulation added to them. Another major loss area would be air inflitration - i.e. leaks through doors etc. Adding lots of insulation to the walls but not insulating the windows and not plugging holes in the floor and walls would not be effective regardless of how much insulation was used.

 

[mog]

I agree that use of Reflectix insulation on windows would be very effective in the cold - even in a roof tent or poptop with fabric.

Part of this is the issue of the use of the "R" value here in North america - the rest of the world tends to use the "U" value instead - which is the inverse of the "R" value. So if the reflectix has a conduction thermal resistance "R" value of 2 (maybe possible but not likely), then the "U" value would be 1/2 or 0.50 - which means that the losses would be halved.

The "U" value is more useful since it provides a direct understanding of the value additional insulation provides - the R value is more "marketable" as its a bigger number and sounds more impressive. Consider the following values

R-value / U value / % / BTU's required to heat

R=2 / U=0.50 / 50% / 6000 BTUs (hypothetically)
R=10 / U=0.10 / 10% / 1200 BTUs
R=20 / U=0.05 / 5% / 600 BTUs
R=50 / U=0.02 / 2% / 300 BTUs

So going from an R-value of 2 (reflectix) to a R-value of 10 (2 inches of foam) results in 1/5 the losses or BTU's required. Adding another R10 - 2 inches of foam - only reduces the losses by 5% more - or requiring 600 watts of heat. Even then adding R50 more - i.e. 6 more inches of foam only saves 300 watts of heat.

So the best bang for the buck is adding any insulation - which is why people probably talk about how adding reflectix insulation made such as difference... because it did cut the losses in half perhaps...

In most vans, the losses through the single pane windows would dominate the losses if the walls had any level of insulation added to them. Another major loss area would be air inflitration - i.e. leaks through doors etc. Adding lots of insulation to the walls but not insulating the windows and not plugging holes in the floor and walls would not be effective regardless of how much insulation was used.

Thanks so much. :wings: Very-very valuable information there.

 

[bdog1]

Great concise info! Wasn't aware that glass was so important. Thx.


Sent by wing, prayer & ATT

 

[southpier]

no one said anything about arithmetic being involved

 

[redneck44]

I've had good results using camp mats, contact adhesive to the metal work, and cut to size bits for the windows, armaflex (fireproof) would do the same thing but the camp mats were cheap and come in usable sizes.

 

[dar395]

!,m just getting started on a new (to me) van and this subject is of great interest. I had talked to a insulation installer (union contractor) that showed me closed cell insulation that would cost me about $950 he than told me that 1/2 carpet padding (8#) with moisture barrier would do the same job at very low cost. If you search the R value you will find it at 2.6. I m wondering if any one has used the carpet padding as insulation and would you do it again?

 

[boardrider247]

Found some more talk over on the sprinter forum about spray foam insulation.
Seems some have done it successfully.
http://sprinter-source.com/forum/showthread.php?t=9677&highlight=Insulation

 

[bknudtsen]

!,m just getting started on a new (to me) van and this subject is of great interest. I had talked to a insulation installer (union contractor) that showed me closed cell insulation that would cost me about $950 he than told me that 1/2 carpet padding (8#) with moisture barrier would do the same job at very low cost. If you search the R value you will find it at 2.6. I m wondering if any one has used the carpet padding as insulation and would you do it again?

Carpet padding will hold a ton of moisture.

 

[Bbasso]

Excellent thread you found, thanks!

 

[hogasm]

Carpet padding will hold a ton of moisture.

There is more than one type of padding. We install a padding under outdoor carpet on decks that is completely water proof. Only costs 25% more than regular 1/2" carpet padding.

 

[bknudtsen]

There is more than one type of padding. We install a padding under outdoor carpet on decks that is completely water proof. Only costs 25% more than regular 1/2" carpet padding.

Yeah, but most folks are thinking of the cheap indoor stuff. The neoprene commercial stuff is pretty slick.

 

[boardrider247]

Well since I am here sitting on my a** with a cup of coffee in front the the wood stove rather then actually out in the shop insulating my van here is some more info.

Great list of links
http://sprinter-source.com/forum/showthread.php?t=209&highlight=Armaflex

If money were no object this material would be the ultimate insulation/sound deadener for a van in my opinion.
http://www.under-the-ice.com/product_info.php?products_id=74

 

[southpier]

good links; thanks

 

[89s rule]

Well since I am here sitting on my a** with a cup of coffee in front the the wood stove rather then actually out in the shop insulating my van here is some more info.

Great list of links
http://sprinter-source.com/forum/showthread.php?t=209&highlight=Armaflex

If money were no object this material would be the ultimate insulation/sound deadener for a van in my opinion.
http://www.under-the-ice.com/product_info.php?products_id=74

Great links. I woudl add: http://store.secondskinaudio.com/ Better than Dynamat at a little lesser price. The second link looks similar to the foam mats you can get for standing on at the Flea Market. ( I bought one last year for the floor of our 4runner when we took a 7K mile roadtrip. I also have a little bit of it from a Junk Yard that a guy had in his van. Spray glue/contact cement and was a beast to remove. He had most of the van lined, but removal almost made me want to just wait and buy some of the foam mats from the Flea Market.

 

[JCTex]

Some res spray on is non-flammable, just have to look. Ditto, ditto on the huge engineering problem: to work, it requires a air gap bt it and living space. Plus, that air needs to flow some. Think how they use it attics w alum strips stapled to the rafters and air going up and out. Can use pink stuff, but doubt that's enough air. In our rig walls, we just can't afford giving room for plain air. Wish we could.

Different densities help, too, I think, as well as canceling out different frequencies of sound.

I know what I'm going to put on as next-to-metal layer: Lizardskin Sound, and 2 layers of Lizardskin Temp Control. I'll have to be careful to try and mask any weep holes at the bottom of the inner wall IF I can see them.

Using water base contact cement, a layer of Reflectix is going next, using 2 layers here and there to flatten wall out some. This is my attempt to introduce some air with the little bubble wrap. Not great, but some air even though it's dead.

The 4th layer will be 1/2" foil-one-side polyisocyanurate. The thickness should allow some bending to come close to my For van's wall. Polyiso doesn't burn and is 3x as effective as styrofoam.

The third layer will be patches of non-paper-backed pink stuff to fill any voids behind the polyiso.

From here to the paneling I'm stumped. I could go w another 1/2" of polyiso but I'm looking for 1/2" of something else w as good or better R, insects won't like, or mice, won't burn, and helps with sound. One possibility is dense foam exercise mats. Another is proper kind of dense carpet, as in low, low VOL.

Like you I'm curious if someone out there knows of some substance good for a metal wall. BTW, already know about Dynamx and RoadKill. Not ruling either out; just trying to do same thing w cheaper materials. I WILL BE using Dynamat thick under my hood and inside engine cover.

JC