HVAC (heating, ventilation and air conditioning) is a big topic when you live in a vehicle. The small space, along with having less insulation than typical sticks-and-bricks homes and no permanent utility connections all mean that keeping comfortable temperatures can be a challenge. Many van dwellers are snowbirds, following mild weather for comfort and convenience.
Heating is much cheaper and easier, since diesel heaters and propane heaters can warm things up pretty quickly without using a lot of fuel. Diesel heaters do draw a decent amount of power on startup and any heater with a fan will need some electricity, but most of the energy they use comes from relatively inexpensive fuel. Propane heating does add a lot of water vapor to the air, so condensation needs to be managed. Electric heating uses significantly more power than any solar power system can provide, so you would only be able to use that while connected to shore power. Some nomads even use wood-burning stoves for heat, although these generally have significant drawbacks.
Ventilation generally requires the installation of powered roof vents. If you don't have a fan, you'll need to regularly keep your doors and/or windows open, which is usually impractical for safety and due to bugs or other animals. Most nomads consider a ventilation fan to be a requirement of any build.
Air conditioning uses a lot of electricity, so cooling your living space via solar power requires a large and fairly expensive electrical system. This expense puts air conditioning systems firmly in the luxury build category. In desert regions with very low humidity, swamp coolers can be effective spot coolers.
Passive cooling through the use of awnings, shadecloth, or shade can help keep sun off the van's interior and occupants. Vehicle color can have an impact too.
Insulation, somewhat surprisingly, isn't required for every living situation and every nomad, and you may be able to get away with less insulation than you might expect. Some people prefer to go without, especially those who follow warm weather. However, most vehicle builds do have at least some insulation, and some have very significant insulation. There are many different options to insulate a vehicle, each with benefits and disadvantages.
Resources
- Kaylee's Winter tips for Vehicle dwelling
Heating and cooling with solar power
These types of large electrical loads can be run with solar power, but only if you have a lot of solar panels, a lot of sunlight, and an expensive battery bank:
- Air conditioning
- instant pot / ninja foodie / air fryers - use pressure cookers instead
- Indoor grills such as a George Foreman grill
- toaster ovens and toasters - microwaves can be easier on the system because of their short running times
- electric coffee makers - use propane to make coffee instead
- electric hair dryers
- electric water kettles or water heaters. Use fuel-burning stoves instead.
- basically anything that runs on a big inverter
The number of beginners who imagine themselves running these greatly exceeds the number of people who can afford to buy the gear, have sufficient roof space for the panels, and the knowledge to get it set up correctly and keep it running. Think about the large gap between wanting a Ferrari and doing what it takes to buy one and keep it healthy. It can be done but most folks have neither the funds or the will to make it happen.
But fear not: most people run much smaller and more affordable solar configurations that meet their needs very well. Used Toyota Corollas work great and won't bankrupt you. :-)