TL;DR - It is technically possibly, but very expensive and complex. Be prepared to spend at least $10,000.

More expensive than the A/C system itself is everything you'll need to power it. A/C takes a huge amount of electricity; you'll need at least 8-12KwHr of lithium batteries, 800-1200w of solar, and the required massive charge controllers to run it all.

And it's still not going to give great results; it might be okay for taking the edge off on a very hot day (bringing the inside of the van down to 80f while the exterior temperatures are over 95f), but you're not going to be able to keep the van at 68 degrees on a hot day just off of solar.

Especially because (rather paradoxically) running A/C off of solar requires that you park your van in the sun; which means the inside of the van will get MUCH hotter than it would if you simply parked in the shade. This puts you in a weird catch-22 where you can't run the A/C without parking in the sun, but parking in the sun means you have to run the A/C much harder than your solar can sometimes keep up with.

This is quite practical, and it's how RVs have been doing it for many years. The A/C systems run natively on 120v AC(Alternating Current) units and are getting power from a generator or shore power.

See this article for a good overview on what may be needed.

Don't say we didn't warn you. If you are reading this you probably haven't done the math. Prepare for some unpleasant news, because at this point you may not be familiar with:

• How much power it takes to run the A/C unit continuously
  • Even the most efficient 12v A/C units draw upwards of 60 amps at full blast; that's over 700w. That will drain even the most massive battery banks extremely quickly.
  • Using a 120v system through an inverter will increase that power draw even more.
• how much power it takes to start the A/C unit (Usually a lot more)
  • Some units have a “soft start” function, using a bunch of capacitors to help the compressor start while smoothing out the massive spike in current draw
• how much solar panels are derated in actual use.
  • If it's hot enough to run A/C it's hot enough that you are already losing 25% of your solar panels' rated output due to voltage depression. That is before wiring and charge controller losses.
  • In order to generate 700w of power to run an average system, you'll need at least 1200w worth of panels. And that's just to run the A/C unit itself. That's not giving you any overhead to charge your batteries or do anything else.
• how much space those panels will require
• how much money those panels will cost
• how much money big solar charge controllers cost

And that's just considering running the unit in optimum solar conditions in the daytime. Running A/C at night requires a magnitude increase in battery bank, and then even more panels that are capable of both recharging the batteries while running the A/C during the hotter parts of the day. See this build thread of someone who does.

There is a reason people snowbird (follow good weather) and use roof vents to control humidity and temperature.

One exception to this dilemma is available if you live in the desert; swamp coolers do a mediocre job of cooling in areas of low humidity. They use very little electricity but a great deal of water, and will only drop the temperatures by 5-10 degrees in even the best conditions.

That's right. People also make 200mph Pintos³⁾ and 20ft tall bicycles.

There are people with an in-depth understanding of the issues, and the money and space to make it happen. It does not stand to reason that the average person with average resources and commitment will make the trip from idea to implementation.

12v/24v/48v DC units do exist and can give some efficiency gains as you don't need to run them through an inverter, but they are very expensive. All-in-one roof units offer a much simpler installation and are usually around $2,000; Dometic has their RTX 1000/2000 units as a good start. The relative ease of install comes at the expense of taking up quite a bit of roof space (and consequently reducing your space for solar panels). Split units separate the evaporator/condenser/compressor into separate parts which have to be plummed together. This can offer a lot more flexibility in terms of where to mount stuff, but also makes the installation much more complex. Cruis-n-comfort and UnderMountAC are the two most common split options, and will generally run $4,000 for the units themselves.

Beginning in about 2023, cheap Chinese 12v mini-split systems have started to come down to almost acceptable prices ($1k in the USA, or as little as $500 if you can wait the 1-2 months for shipping from China). Reports on them have been mixed; they come with almost no instructions and often missing a few minor parts (most users report some fittings or couplings being missing, or needing to crimp their own lines). Warranty and installation support is non-existent, but if you can fiddle your way through the psudo-DIY installation many people have reported generally positive results.

120v roof-mounted A/C units can be had for as little as $500 and are very common in the rest of the R/V world, so if you can find a big enough inverter it can be cheaper to go that route.

If you would like to learn more about how it's been done before, start with this post by trebor then check out posts by people who have done it:

• Pleasedontmindme247
• WorkingOnExploring – exceptional walk-through of the power and equipment needed to run A/C in a highly-insulated truck camper.
• jimindenver (youtube)
• iTripper
• TucsonAZ
• IGBT
• BradKW
• SolarInTheCity
• Van Gogh
• Undermount AC install on a Transit

Also see

• this thread on DC A/C options and
• daficco's advice on installing a mini-split.

Commercial RVs and travel trailers typically power their single A/C off 30A (3,600W) shore power, and sometimes can't run that and a MW at the same time depending on other loads. Dual A/C typically runs off 50A (12,000W) shore power.

When away from shore power they run generator power into the shore power port.