Air cavity insulation

[cargoconvert]

First post, so please forgive me if this has been asked. I'm still in the planning process for my CTC.

Has anyone considered sealing the wall and ceiling wood materials to create an air cavity between the skin of the trailer and the wood?
I know that foam insulation is popular, but air alone could also serve as insulation if a seal could be made.

FWIW, I live in the Northwest, where temps rarely go below freezing or above 90.

[GuitarPhotog]

Compared to almost anything else (except metal perhaps) air is a terrible insulator.

Air has an R-value of 1.0, almost anything is higher than that, for example my 1" rigid styrofoam insulation is R-4.

I suggest you fill those air cavities with an additional form of insulation.

<Chas>

[cargoconvert]

I suggest you fill those air cavities with an additional form of insulation.

Thanks for the advice. I'm evaluating the need vs the effort and cost.

[angib]

A wall with an air cavity in it is a much better insulator than a solid wall. It's not that the air is an insulator*, but that any heat has to transfer twice more between wood and air and it's the 'effort' of transferring between materials that reduces the heat flow.

Of course I work in metric numbers but I think just a cavity on its own rates as R-1 in US units.

*Air in a cavity is a very poor 'insulator' since it is free to move around - even a 1" gap is enough to set up a thermal current where air goes up the warm side, gets heated, then drops down the cold side, giving off heat. It's the same reason why thick gaps in double glazing are not as thermally efficient as moderate gaps (say, 3/4").

[Engineer Guy]

I'm a huge fan of [super] Insulation because it's a game changer. It allows heating or cooling a volume with much less Energy, regardless of volume size [House or CT]. I built a super Insulated Solar House, and have just finished really packing in Insulation in a used/Display Model Garage/Shop/Workout Area/Guest Cabin we got delivered and set up for a $$$ song.

1. Air is a good conductor. This is why Thermos Bottles and Flasks have Air pumped out between the inner and outer surfaces. Otherwise, the product inside would quickly come to the same temp as the outside environment. If you don't insulate, the inside of your CT with you in it will constantly be doing the same; especially in direct Sun if it's a dark color.

It's not possible to seal any moving Vehicle so tightly that Air would remain sealed in a cavity.

2. Most all Insulation traps Air 'bubbles' and keeps those bubbles from making contact and transferring Energy [Heat or Cold]. Ma Nature does not like temperature differences, and those differences always try to come to equal temperature.

3. 'Closed Cell' Insulation, like 'Styrofoam', is popular. I also like 'Reflectix', which is a layer of sealed-closed Air 'bubbles with an Infrared-reflecting surface that installs to face the lived-in volume. It works exactly like a 'Space Blanket'. Neat stuff to install just under the inner Walls...

Late on a warm afternoon, go inside an unshaded, uninsulated 'Tuff Shed' in a Pal's Yard or a local Big Box Store and note how ghastly hot it is.

Insulation will extend the usefulness of your Project by allowing you to comfortably Camp more in less-than-ideal temperatures.

[Helixpteron]

For the best of both words, insulate with Reflectix, and leave an air gap!