Teardrops n Tiny Travel Trailers

Good people of TNTTT,

As most of you know, conventional insulation materials have an R-value of R-3 to R-8 per inch (in truth, marketed R-Value is a gross oversimplification, since the R-value of material fluctuates based on age, dominant heat transfer mode, etc). Anyhow, back to the topic. Vacuum insulated panels have an R-value of 20-40 per inch!



They work similarly to a vacuum thermos. Once you factor in edge effects and other compromises, it's more accurate to estimate R-15 to R-25 per inch for a whole-wall assembly.

However, cost is substantial. While a 4x8 1-inch thick of insulation foam (R-4.2 to R-6.7) can be had for $11 to $30, a 4x8 panel (or equivalent) VIP might cost $400+ (gulp). They also suffer from the obvious flaw that if punctured, they will lose a great deal of their effectiveness.

I don't really have a point to this post I doubt that VIPs are remotely cost-effective for manufactured or DIY teardrop shell use. However, if someone had the time and money to splurge ... you could build an Arctic-quality camper on a very small footprint! Or VIPs could have selective use, such as encasing water tanks. Someone who's retired from being a neurosurgeon should try them out!

I'm intrigued by Aerogel. aerogel.com. Spaceloft is an Aerogel product used for insulating buildings. https://www.aerogel.com/_resources/comm ... eet-EN.pdf A Google search for "rigid foam board R value" showed that Aerogel has an R value of R-10 to R-30 per inch.

Because you have to exchange the air so you don't suffocate, there's a limit to how much insulation makes sense.......Unless you want to put a heat exchanger on your fantastic fan.

Plus you've got windows and doors (and often the floor) that tend to have a lower R-values that will limit the R-value of the trailer as a whole no matter how well the walls are insulated.

Pmullen503 wrote:Because you have to exchange the air so you don't suffocate, there's a limit to how much insulation makes sense.......Unless you want to put a heat exchanger on your fantastic fan.

Plus you've got windows and doors (and often the floor) that tend to have a lower R-values that will limit the R-value of the trailer as a whole no matter how well the walls are insulated.

You've the nail on the head! A chain is only as strong as its weakest link. When I consider that, by adding R5 insulation to my plywood walls, I've roughly improved insulation 500%, I'm
a happy guy. But in order to improve another 500% compared to R5? Well, then I need R25 walls! That's 4-6 inches thick! No siree. And when you consider the limited thermal mass of a camper, and the requirements for constant air exchange, a super-insulated teardrop just doesn't make much sense.

My original thought process was in line with that of Halfdome Danny's; VIPs could be used to reduce stolen space and maximize utilization of 4x and 5x construction materials. Cost-effective? Eh ... probably not. But a fun future to look forward to!

Esteban wrote:I'm intrigued by Aerogel. aerogel.com. Spaceloft is an Aerogel product used for insulating buildings. https://www.aerogel.com/_resources/comm ... eet-EN.pdf A Google search for "rigid foam board R value" showed that Aerogel has an R value of R-10 to R-30 per inch.

Thanks for the interesting product. I was reading the European data sheet (https://www.aerogel.com/_resources/comm ... eet-EN.pdf) on Spaceloft. Interesting stuff ... it has a US R-value of about 10 per inch, which is better than any conventional insulation, but beneath that of VIPs. With that said, performance of a VIP will decrease as it ages. My armchair research indicates the rule-of-thumb-industry standard for minimum VIP performance seems to be about R-18/inch after a 25-year life.

I was also reading a thread at Green Building Advisor about using Spaceloft on a residential reno, and it made me glad I work with small campers where I can afford premium materials! How'd any of you like to pay $200,000 for a Spaceloft roof? (https://www.greenbuildingadvisor.com/qu ... nly-option).

halfdome, Danny wrote:Very interesting
To make a conventional wood framed and skinned teardrop without loosing too much space to insulation.
My first build was well insulated but we lost some interior width to insulation.
Wonder how well it keeps sound out, vs regular foam?
Wonder where it can be purchased?
Danny

I know some pieces can be bought piecemeal from refrigeration parts websites. Beyond that ... good luck :p

I recall the first time I learned about Aerogel. I read about a proposal to use Aerogel tape between house framing and drywall to substantially reduce thermal bridging thereby increasing the structure's effective insulation value.

I have wondered how much insulation is (optimally) needed for a teardrop trailer. Many manufactured and home made teardrops have plywood side walls with no additional wall insulation. Most have insulation in the roof. Some also have plywood floors with no additional insulation.

Neither Camp Inn, Vistabule, or Oregon Triail'R insulate their walls or floors. They are three of the higher quality teardrop trailer manufacturers with many highly satisfied customers. Teardrop trailers are seldom used for all four seasons, particularly not in the coldest parts of winter.

As a home builder I/you/we can insulate my/your teardrop better than most manufactured teardrops.

My plan is to insulate the floor and the cabin/galley bulkhead with 3/4" (~R 4.5) polyiso foam board, the cabin's side walls with 1" polyiso (~R 6), and the front wall, roof and galley hatch with 1-1/2" (~R 9) polyiso. The goal is reduce the teardrop's weight, reduce condensation on interior surfaces, provide some soundproofing, and to be more comfortable whether it's hot or cold outside. The outside will be painted white to reduce strong sunlight from overheating the cabin. It should be very comfortable almost all year round.

Esteban wrote:Neither Camp Inn, Vistabule, or Oregon Triail'R insulate their walls or floors. They are three of the higher quality teardrop trailer manufacturers with many highly satisfied customers. Teardrop trailers are seldom used for all four seasons, particularly not in the coldest parts of winter.

I think therein lies the important fact. It's not that an Oregon Trail'R camper isn't insulated; it's that the mattress insulates the floor, the roof and "front wall" has 1-1/2 inches of insulation, the rear wall is effectively insulated by galley dead air space, and the remaining wall space is mostly taken up by doors and windows anyway.

I agree that plywood walls are sufficient for 2- and 3-season teardrops. My interest in VIPs/composites, like yours, isn't to over-insulate. Its because VIPs or composite structures, which often have foam cores, offer significant weight savings and improve soundproofing and interior condensation.

I'm not telling you anything you don't already know, Estaban. But someone else reading might fall into the pit of believing uninsulated walls = uninsulated camper (e.g. Oregon Trail'R),and that just isn't the case. You need insulation in a teardrop. But the walls are probably the least important place to add it.

being cold in a TD has never been an issue for me as long as I had shore power. Put a ceramic heater in it and you can be chased out. With the vent open an inch or so and a side window open about an inch for fresh air, I've kept warm enough to sleep comfortably even to below zero. The problem is what you do when you climb out of bed. I've camped in weather that was so cold that everything in the galley froze due to the air temperatures. Frost build up on metal doors and places where there wasn't insulation even although I had 1 1/2 inches of wood in my side in some places was the issue. Staying warm was not.


Art