Baffle the Interior for Cooling or Heating

2018-07-23 • SEND FEEDBACK •
Related: Mercedes Sprinter

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Discussion here refers to the 2017 Sprinter 2500 (144" short wheelbase) cargo van which I have now insulated quite well so that not much heat gets through.

This page discusses a simple trick to keep cool while driving in extremely hot weather (95°F and hotter), or to sleep much more warmly in extremely cold weather.

• In my 2017 Sprinter, the factory A/C is sufficient at 95°F to keep the cabin comfortably cool for the driver and passenger while driving, but the mid and rear areas of the van remain relatively warm, perhaps 20°F below ambient, e.g., 90°F if it is 110°F outside. When it gets even warmer, pointing the outlets directly at the body keeps things comfortable, but that’s the limit of the built-in AC.
• If it gets seriously hot (100°F up to 115°F), the factory A/C is incapable at idle of keeping things cool enough when the van is idling/stopped because the A/C is just not getting the airflow it needs. Sometimes I stop for half an hour or an hour of computer work. In such conditions, continuous idle with the A/C on high is barely sufficient and while the heat is manageable, it becomes a physical stressor.

I have neither the funds nor the inclination or desire to install a rooftop air conditioner, with its added complexity, bulk, weight and power requirements. What then?

Baffle the Interior for Cooling or Heating

I have steadily improved the insulation to what I now deem excellent, but baking sun or overnight temperatures in the teends adds up so that no amount of power short of continuous idling will do—and that’s obnoxious for both occupant and anyone nearby, not to mention a fuel guzzler (0.8 gallons per hour).

Why make the air conditioner cool the huge volume of the entire van (or the heater heat the entire van)? During the day the only areas (for me at least) that are really in use are my desk and the driving compartment, so it makes sense to baffle the space so that the A/C need cool less than half the volume of the van*.

* Appropriate measures should be taken while parked to block the ingress of heat through the windshield and front windows and side windows. Sunlight adds a massiv heat burden, so any reflective material makes a huge difference.

To be effective and convenient, a baffle should meet these requirements:

• Ultra light weight so that magnets to a roof beam can instantly add or remove it (velcro would work for those who have buried the steel under carpet or similar, but it is much less elegant).
• High insulating power to keep cold or heat in/out.
• Multi-purpose, not something extra to carry. A comforter can also be used for sleeping, or for temporarily insulating a side of the van for times when the hot sun is beating on the van, or a sub-freezing wind is sucking heat away.
• Tall and wide enough to baffle the air volume to minimize the flow of air.

Any comforter or blanket or even a tarp or similar will make a large difference. However, the very best solution for its ultra light weight and ultra high insulating power is the Western Mountaineering Cloud 9 comforter. I recommend the Queen size as most versatile, but Twin will do just fine also, and is easier to work with if the goal is to insulate, say, a wall on a cold windward side, or sun-baked side.

Western Mountaineering Cloud 9 Comforter: ultra light but ultra high grade down for very high insulating power, warm or cold