Monday, February 5, 2018

Thermal Pack For FWC Camper

Above is from Four Wheel Camper Website describing the Thermal Pack they sell and what it does.

Last fall when I was working in my garage in the camper I ran the electric heater on high to stay comfortable inside.

It became obvious to me that I needed some kind of thermal insulation for the temperatures I experience on my travels in the camper..

I looked at buying FWC Thermal Pack and it was $600.00, I believe without shipping.

This is a significant expense and I contemplated making my own.  If I was to make it, I would appreciate my wife’s expertise and her sewing machine.  Lucky for me she agreed to the project.

I researched material and I found the above material bolt in JoAnn Fabrics to sandwich the insulation material.  This covering material is slippery to move freeley opening and closing the camper and it breaths.

I searched the internet and settled on InsulShine as it seems to meet the needs. It reflects heat and has insulation, and is often used for insulated food bags.

The first step was to measure and make both sides of the camper thermal lining and seal the InsulShine in between the material.

Note: There is Velcro strip at the top and bottom of the camper’s expansion sides to hold the Thermal Pack in place.  It comes this way from the factory.

Above Velcro is now installed on the top of the thermal liner we were making.

Above the thermal liner has Velcro on the top and bottom, but no windows cut yet.  By now my wife was a bit frustrated sewing the seams and then sewing the Velcro on the top and bottom with her non commercial sewing machine.  She persisted.

This next step looks simple but it’s not.  The windows needed to be cut open and then Velcro needs to be added to the edges of the window opening.

Discarding the window cutout pieces we now made the window coverings with Velcro on all sides.  The cut out pieces are not large enough to overlap the opening.

Then the window panels are put in place.

Here is the important step.  Once you have the insulated panel in place with the windows covered, feel the rivit that holds the “D” ring tab and mark the insulating panel with a dot on the rivit head.

The “D” ring and tab on the FWC material is used to pull the sides in with bungee cord, when closing the roof

Then you remove the thermal window and put a button hole just below the rivit so the “D” ring can fit through.

Above the final window panel is in place with “D” ring through the newly installed button hole.

Above, I have opened the corner of the thermal panel and window and the window cover that comes with the camper.

You can see the thermal window is bigger in all directions than camper window.  This allows the windows to open and close nicely.

I took this picture on an 80 Dee day.  The thermal pack we created works to keep heat in and cold out, as well as keeping the hot out and cool in.  Both keeping heat in and heat out are important to make your stay more comfortable.  If you want to let heat in, just remove the thermal windows and heat or cool can come in.

By the way, my wife said it was more work than she expected and she doesn’t want to make anymore. 

How does it work - it works great.  Only one issue is that the aluminum covered Mylar blocks radio waves and I need to stick my telescoping antenna of my radio under the Velcro window to get a better signal.

The aluminum coated Mylar is unused on home greenhouses to keep heat in longer.



  1. Thanks for posting this. I've been thinking of doing something similar. I looked at the same fabric store and wondered if I could use ironing board material. It sounds like it might do the same thing. Do you have any thoughts on other materials? I thought about just using wool. Yours Greig

  2. Greig,

    I did think of using the ironing board material but wanted the reflective Mylar surface of the insul products to reflect heat in and out, and in use last year it does.

    It’s great to keep heat out and heat in but it comes at some difficulty to make.

    The next thing is that I wanted material that does not hold moisture. Heating, cooking, and living in the FWC creates moisture and the insul product does not hold the moisture that does happen. Also the material I chose for covering the insul product does not hold moisture. I don’t know about the ironing board material for retaining moisture but wool will.

    Lastly, I wanted a material that would fold nicely when lowering and not bulk up and require messing with when picking up camp.

    I do know that anything you put up will help thermally. I often sleep on my lower bunk I made and not always raise the roof at night. This helps a lot to keep the heat in. If you raise the roof a barrier to the overhead sleeping area also helps with heat loss.

    If I can help further please go ahead and ask.