Keeping Warm
While many people avoid camping in colder weather, traveling in the shoulder seasons or desert climates often means overnight temperatures in the 40s or even 30s. Others, especially skiers, routinely find themselves in sub-freezing temps. The good news is staying toasty in cold weather is very achievable even though many van campers are drafty and poorly insulated. Here's how. You can also read more on my blog here.
Cold Weather Camping
All van campers from established manufacturers will have a heater. Some super premium models have hydronic in-floor heat. But the vast majority use propane as a heat source and a 12v fan to circulate hot air -- a combination that uses relatively little battery power to keep you warm and works well when boondocking. But there are two challenges you will want to address: condensation and drafts.
Condensation
Condensation is caused by temperature differences between warm interior air and cold surfaces like windows. You can minimize (but not eliminate) condensation by using Reflectix or another thermal barrier in your window wells, which helps prevent warm, moist air from contacting a cold window.
Drafts & Thermal Barriers
Cargo vans are not designed to be hermetically sealed. On the contrary, they intentionally have ventilation so that air can escape when closing the sliding door (otherwise it's actually harder to close) and moisture can exit. Doors can also be drafty due to poor alignment. Adding thermal barriers like blankets or curtains to the rear doors, cab and sliding door is the easiest way to reduce drafts and keep warm air inside.
Electric Heaters
If you're plugged into shore power, here's a pro tip: use an electric ceramic heater as your primary heat source. It produces the driest heat, which minimizes condensation, and can be incredibly effective at heating the van. Sometimes too effective! They're also much quieter than a propane furnace. Units with a thermostat and both 1500w and 750w power options are best. Make sure it also has an auto shut-off feature if tipped over. Using an electric heater while boondocking will deplete your batteries quickly.
When to Winterize
"When do I winterize?" is a tough question, and getting it wrong is expensive. To some extent the answer depends on your van design: are water lines inside and tanks heated? But even poorly insulated vans with exposed plumbing can handle brief periods of time in the high 20s. This is where Facebook groups really shine: ask the community for their experience and recommendations.
Insulation
Another important factor is insulation. Your van camper may or may not be well insulated (especially the doors), and that can have a huge impact on temperature regulation. Improving the van's insulation is a relatively complicated DIY project, but it's possible.