Insulating your vehicle from heat and cold

Opinions vary on the value of vehicle insulation. To decide whether insulation well help in your situation, it’s important to understand exactly what it does. In the winter, heat rapidly escapes the vehicle when air currents either escape directly through vents or make contact with conductive metal that transfers heat to the frigid air outside. Insulation creates a barrier that prevents currents from directly contacting those conductive surfaces.

In the summer, the most intense heat enters the vehicle when sunlight penetrates the windows and is absorbed by the materials inside. There is also some heat transfer when warn outdoor air contacts the van, but sunlight is the real culprit that needs to be dealt with by reflection or shading.

So, in the cold of winter, insulation can make it much easier to maintain a comfortable interior temperature. On the other hand, insulation on hot summer days just tends to trap more heat from the sun, making it harder to cool the interior down without resorting to expensive air conditioning.

Regardless, you definitely want to seal up any cracks or openings that let air travel freely between the interior and exterior. You can use windows and fans to control air flow as needed.

If you do decide to insulate, the first things you want to consider are the ceiling and the walls, where the largest amount of heat will escape in the winter. If your sleeping mat will be in direct contact with the floor, you may also want some insulation underneath to stop your body heat from escaping through the floor. But for the most part, a layer of carpet is enough floor insulation to keep your feet out of direct contact with cold metal.

Using product called Reflectix in the windows, or even the shiny Mylar material from a cheap solar blanket, will directly reflect sunlight as well as some heat when used properly. This works well to reflect sunlight through windows, but it will not work as “insulation” for the rest of the vehicle. For true insulation, you need something that can trap a mass of air.

To further slow down air currents, you can set up curtains to form a barrier between the cabin and living area, and perhaps between other sections of a larger van. A curtain doesn’t have much insulating value on its own, but it creates an extra barrier to slow down the movement of air. Think about how thin a tent is versus how much body heat it can retain on cool nights (if the tent isn’t huge!).

Foam board insulation

Polystyrene foam boards provide a fair amount of insulation and are relatively easy to install on flat surfaces such as found in box truck trailers. Cargo vans and minivans don’t have a lot of flat surfaces, but with a bit of care, you can cut the foam boards to fit in snug along curved surfaces. Styrofoam is nice because it doesn’t have the safety hazards that come with fiberglass insulation.

Insulation also hides wiring

If you are also planning to install an electrical system throughout the van, insulation gives you a chance to hide the wiring from view while preventing some heat from radiating into the interior. There isn’t a lot of specific advice to give about wiring at this point because everybody’s needs are so varied. Suffice it to say, it’s vitally important that your wires be well insulated (electrically) and thick enough to handle the current without emitting heat that can pose a fire hazard. You may also run wires through a conduit providing a barrier between the wiring and the insulation.