WHEN I DECIDED to ditch ordinary life and live in a van I read all the what-to-do and how-to-do-it articles and watched all the videos. Most of them said to insulate. It seemed like the prudent thing to do. One summer day decades ago I had ridden in an old car that had most of the interior gutted. It was like an oven even with the windows open. The bare roof was too hot to touch. And I had spent a couple of winters in Central Canada where not only would your tongue freeze to a flagpole, but your hand could freeze to the bare metal walls of a school bus. So, yeah, insulation is good. 

But how good? After nine years in the van my general impression was, “Except for the times of perfect weather, it’s usually better in here than out there.” Opinions are good, but data is better. So I bought an indoor/outdoor thermometer and took some readings.

About my van

My 2007 Chevrolet Express cargo van has no side windows in the back. There’s two inches of extruded polystyrene board in the roof and walls. The floor is covered with the factory provided jute-backed rubber mat and some throw rugs. There’s a curtain between the cab and rear compartment. I use some Reflectix over the back windows.

My test

The forecast was for sub-freezing nights with strong winds — a good time to learn how well my insulation might work. So I turned off any heating devices after dinner and let the van cool down. The only thing producing heat was my body. I dressed warmly until I went to bed, then stripped down to my undies and slept under a down quilt.

The coldest part of most nights is around 4:00, after everything releases any stored heat. That’s when I got up to check the thermometer. Here are the readings from consecutive nights:

No, it wasn’t toasty warm, and I didn’t expect it to be. Vehicles aren’t air tight, and the van isn’t as insulated as a refrigerator truck. But it was certainly more pleasant inside than outside.

Is a 15° difference worth the cost and work of insulating a vehicle? It is to me. I can get through the night without running a heater, and in the summer I’m sufficiently comfortable without air conditioning. But, of course, I avoid seriously cold regions and horribly humid ones. My two years in Canada and 30+ years in the South taught me that.