EcoRenovator (
-   Conservation (
-   -   Small camping trailer venting in cold weather (

skyl4rk 01-26-15 06:08 PM

Small camping trailer venting in cold weather
I have a small cargo trailer converted to a camper. It is a 4'x8' trailer and it has 1" foam insulation.

Cargo Trailer Camper - Imgur

I slept in it this weekend with 32F outside and here is the dilemma:

If the windows are closed up, it will start to warm up a bit and get comfortable, but eventually you need fresh breathing air, so you need to open the windows. Then it gets cold again. It is not bad as long as you stay under a sleeping bag and cover your head. But as soon as you get out of bed, the cold hits you.

I am trying to figure out a way to get fresh air to my sleeping area, but to temper it a bit so it is not so cold. Opening a window is hard to control how much cold air is coming in, and the cold air just flows around, rather than being moved to your head, where you want fresh breathing air.

My thought is to put a pipe through the floor, with a pc fan underneath the trailer. The pipe would extend up to near the pillow on my cot so I would always have a good supply of fresh air. Hopefully the pipe would warm up the air a bit.

I was trying to think of ways to improve this to keep as much heat in the trailer as possible. for example, use steel stovepipe to increase the surface area to transfer heat, but keep the supply and outlet diameters smaller to limit the amount of airflow. I am thinking (guessing) that a one inch to two inch diameter vent would provide enough fresh air using a pc fan as a blower.

Maybe even make up a small heat exchanger from coroplast as in the other heat exchanger thread. I am not sure it is worth it for my trailer project but it is interesting to think about using body heat as the main source of heat.

I am wondering if it is possible to heat a small insulated box using just body heat. How many R's of insulation would it take to heat a 4'x4'x8' box? If the box were made of iso foam panels, how many inches would it take to stay warm? The ventilation question complicates things but if there were a good heat exchanger, you might be able to build a tiny-tiny house/box requiring no external heat.

That would be the ultimate shelter, requiring no heat other than body heat.

ecomodded 01-26-15 07:33 PM

With a wood stove the air gets changed for you as part of the burning process.

If it was my trailer I would make a mini wood stove from a 20 lbs Propane tank then make up a stainless steel surround that has a air gap behind it with a second piece of (cheaper) steel behind it , on 1" spacers that are secured to the wall.

For the floor I would tack down more stainless (to prevent rot this time) then put bolts threw the floor with about 2" above floor to secure the base. For the base I would pour a mini pad of fireproof concrete complete with a lip on it to keep debris in.

The intake that's on the floor would work well for a stoves intake. Finally buy a commercial 3 or 4" stove pipe kit with a removable stack, and a plug so you can remove the pipe and seal it when needed.

If you do not weld , you can pay a welder to make the stove or just buy a little prefab one.

You can buy kits to make them as well.
If you are so inclined you can burn waste wood.. beach wood or branches and even coal.

I have had this mini stove idea for awhile , one day i hope to build a Aero trailer from my 2007 250lb 17ft. boat trailer which is rated to carry just 1000 lbs.

My brother has a diesel oil cook stove on his Boat , nice and toasty , it uses a gravity fed tank to supply the fuel, mind you its full size his boat is 42ft , but they make smaller ones for smaller boats. *Near* any stove for a boat will be suitable for a trailer , as long as it has a chimney.

NiHaoMike 01-26-15 08:16 PM

Build a small HRV.

gtojohn 01-27-15 02:44 AM

I second the mini hrv. Its not the R-value you need a heat conductor under your bed to move your heat. An aluminum channel recessed in the floor with an opening to the interior on one end and exterior on the other might be all you need. Put the fresh air side by your head and you lungs can be the fan. The computer fan might move too much air. If you move too much air under you it might make a cold spot. Judging by the snow in your pics you camp in a much colder environment then I do. I use a US military bag rated for 0 degrees. Works great on the ground in an open tent, its kept my snug down to the 20s. Sleeping in thermals makes a world of difference.

skyl4rk 01-27-15 05:23 AM

I have some ideas for a heater, but I would like to explore using body heat before getting into a a heated design.

I like the aluminum channel on the wall idea, that is better than a vertical pipe because it takes very little interior room.

I could install a 3" cable hatch near my feet as the outside opening, and run six feet of aluminum channel along the wall at about 3 feet high, with the open end of the channel on the wall above my head.

What type of things can I do to make sure there is adequate air flow? I could open the vent near the roof, but that would let warm air out. I would prefer to exhaust cold air, which is near the floor.

redneck 01-27-15 09:17 AM


A round 2" hole in the floor with the vent window opened a 1/8" should handle
the ventilation with no problem along with minimal heat loss. It requires no power and is self regulating.

You could try raising the bed height towards the warmer air near the ceiling.

If supplementary heat is still required, consider using a 12v electric blanket. Most use 4 amps or less and are relatively cheap ($25-$50).

However, if it were me and I was cold. I would just get a belly warmer. ;)

Maybe two, if it's really cold... :D


ecomodded 01-27-15 10:48 AM

For body heat warmth i would wear a balaclava to bed along with kick *** sleeping bag. Done

If your camping in the driveway and connected to a electrical outlet there should not be any problem as far as heat is concerned , add a cheap trailer skylight vent to give you control over the venting.

Not a new idea but a good one that does not require electricity or stringing vent pipes.

skyl4rk 01-28-15 05:49 AM

Here is an idea to temper the incoming air:

Cut a hole in the side wall, just below the cot bed level where the sleeper's feet are. Put a piece of 1" copper tube through the wall as a cold fresh air intake. Put an elbow on it and add about 6' of copper tube along the wall. Then elbow the tube up so that fresh air is directed to the sleeping person's head (warm fresh air supply).

To make this better, put the copper tube inside of a 1-1/2" plastic pipe with tees on each end. At the foot end of the cot, one side of the tee fits flat against the wall and the copper tube exits the wall through that tee opening. The other foot end tee opening gets a pc fan blowing into the the plastic pipe (warm cabin air vent). On the head end of the plastic pipe, one tee opening has a cap with a hole drilled to allow the copper tube through. The other side of the tee passes through the floor to allow exhaust air outside and to let condensate drain to the ground (cold cabin air exhaust).

ecomodded 01-29-15 07:45 AM

You could rig up a prototype temporarily and see how it performs if it meets your expectations then you can install it permanently.

I still like the sky light Vent as it will give you light as well as a easily tunable fresh air supply.
They are stupid easy to install and are comprised of two pieces you sandwich together , they only cost $30 :-)
I have a feeling in the summer you will be in need of the roof vent anyways.

When I was in my 20's I lived in a 17ft trailer for a year , the roof vent was the kitties meow and a daily part of life in the trailer.
As your trailer has no windows even with a roof vent you would need a bigger floor vent in the summer or have the current one fan powered.

skyl4rk 02-01-15 06:24 PM

Here is a video of the trailer in 20F with a lot of wind. I am venting pretty much as redneck described, about 1 square inch opening in the floor, with the roof level vent cracked open. With an electric heater, everything is cosy warm.

I am not going to try sleeping in it at 20F tonight, thanks.

I am still interested in a heat exchanger, because I would like to build a foam teardrop type camper. Using 2" insulation foam, build a 4'x4'x8' box on a trailer. I am interested if this type of foam trailer could use body heat to keep temperatures up to about 50F in the trailer, even in blizzard conditions.

An efficient heat exchanger could make this type of small shelter independent of a heat source.

ecomodded 02-01-15 06:52 PM

Its a nice little trailer
I somehow missed that your trailer had a window on the side and a vent up near the roof.

which is why I was pushing the roof vent like it was all important.

Your set for ventilation , with your head at the floor vent end you would probably get fresh air to breath , which is always nice.

gtojohn 02-02-15 08:56 PM

Good idea, copper pipe idea should work like a mini hrv. Just remember the slower the air moves the more time it will have to warm up.

All times are GMT -5. The time now is 06:10 PM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
Ad Management by RedTyger