While Heating your Skoolie is pretty straightforward (You'll most likely go with Propane, Wood, or Diesel), coming up with a way to Cool your Rig is one of the most difficult obstacles to overcome when designing your Skoolie, Shuttle, or Van Build. There are a lot of variables in both your lifestyle and personal preferences that make it hard to get a clear picture of what you need, especially when you're just starting out. - It seems like you'll either be giving up comfort or spending a lot of money to maintain it.
While there is some truth to that, there are many things you can do to find a happy medium. Perhaps the biggest of which is to simply rethink the way you use Air Conditioning, and try to schedule your travels to minimize how often and how much Heat and A/C you will need. Additionally, taking advantage of Shore Power (or a Generator) whenever you know you'll be needing to cool the Bus for long hours, or have to stay in a hot climate for an extended period, can cost much less than doubling or tripling the size of your Solar Array and Batteries. - Remember, you can always upgrade or add Solar Elements, as needed, once you're on The Road. - Please have a look at our 10 Tips To Save Power and our Solar Cheat Sheet for more info.
We'll jump right into the FAQs about Air Conditioning first, and then discuss some creative options.
What's the Best RV AC Unit for a Van or Skoolie?: - “The Best”, in this case, is really whichever is the Most Efficient for your personal use and space. We'll get into more detail and numbers later in the blog, but here are our top picks for each vehicle type (and one for Stealth Camping). Click the images for pricing. - More options are available on the Heating and Cooling Page.
Best A/C for a Van: - If you're in a Sprinter, Transit, or Cargo Van, the on-board Air that came with the Rig is actually the most efficient. - Obviously you don't want to run the engine all the time, and you're limited on space. - With some Creative mounting, you could use a Window Unit like the one shown in the next section, but the Zero Breeze Portable Air Conditioner runs on 12 volts and comes with an optional Lithium Battery. The unit is a bit expensive, but will minimize the strain on your Solar System. - It's a good solution for a Van Conversion, Short Bus, or even a Small Shuttle or Box Van. - If you use A/C wisely, it may be the only thing you need. *Use the discount code OUTDOOR5 and receive an additional 5% off.
Best A/C for a Truck Bed Camper or Small Trailer: - The Zero Breeze (featured above) would work well in this scenario, but a Small Window Mount Unit is a good choice for the budget conscious. It will be more efficient than a Portable, and less expensive up front. (You can even use one you already own!) They're not really designed for travel, so you'll need to get creative in how you mount it to the Rig, but it's a great option.
Best A/C for Stealth Camping (or Limited Build): - Nothing says “Look at ME!” like a buzzing, dripping, metal box sticking out the window of a parked vehicle. - If you are looking for a more subtle option, or perhaps can’t find a good way to wedge a Window Mounted Unit into your Build Design, you’re going to want to go with a Portable. - The Zero Breeze (featured above) is still the best option for a small Rig, but for those with larger spaces or a tight budget, a Large Portable is a good fit. The one featured is rated for 400 Sq. Ft. and 12,000 BTU at only 9 amps (Smaller options are available). - Consider using a Roof Vent for the exhaust hose, rather than an open window.
Best A/C for a Short Bus, Small Shuttle, Mid Size Trailer, or Box Van: - You could use a Portable if you don't want something sticking out of the Rig, but a Window Mount Unit is probably your best choice for cost and efficiency. 5000 to 8000 BTU should be more than enough. You could consider a small Mini-Split or Roof Mounted Unit if you spend a lot of time in the heat, but if you typically don’t, it's probably overkill.
Best A/C for Skoolie, Large Shuttle, or Box Van: - The Mini-Split is all the rage in the Skoolie world, and with good reason. While they’re a little more expensive, and can be difficult to install, they are far superior in Cooling, due not only to technology, but also because the “guts” are mounted outside of the living area. - A Roof Mounted RV A/C is also a thought if you don't want something protruding, or you simply prefer using one over a Window Mount or Mini-Split in your Bus (due to limited Build Space, for example), but Roof Units tend to be less efficient than other options. - If you're on a tight budget, a Larger Window Mount will work also. (See Chart below for sizing.)
Supplement!: - Regardless of what size Rig you own, or what you choose for your House A/C, an inexpensive Evaporative Personal Air Cooler, coupled with a Roof Vent Fan, and a few USB or 12 volt fans will be invaluable. Often times, with proper use of these, you can avoid using the A/C altogether. (More on this later.)
What about Diesel?: - While we can't personally recommend it, we've known a few people who are happy using a Diesel Heater/Air Conditioner unit for both. - If you know you'll be using A/C regularly, have a minimal Solar Setup, and aren't worried about the environmental impact, this is definitely worth exploring. We link to a few on our Heating and Cooling Page.
Can I run an RV AC Unit on Solar Power?: - Yes, you can... - However, the amount of power required will come with a very large price tag. This is why we recommend only using A/C when connected to Shore Power or a Generator if at all possible.
Whether connected to Shore or Running on Solar you'll need to address the “Spike” your AC Unit will draw on the electrical system when it starts. - If you are running any type of 120v A/C Unit, you should include a “Soft Start” to limit the initial Spike (Peak), and reduce the risk of damaging your Electrical Components. Click the image for details.
Tech Tip: In addition to the Soft Start, it’s always a good idea to fire up the Generator before you switch on your A/C. This will help stabilize the Power and minimize the initial Battery Drain.
How much Solar do I need to run an RV AC Unit?: - If you are designing a new Build you have the advantage of being able to adjust the numbers from the beginning. - Get the most efficient A/C Unit for the space you use, and then size your Solar Setup accordingly. - Your Solar Panels can do most of the work while the sun is shining, but you'll need Battery Capacity (Amp Hours) to balance it out, and to continue to run A/C into the night. Additionally, you'll need a larger Inverter to handle the Power that your A/C uses.
It comes down to the Wattage and Amperage that the unit draws. We have a chart below, but your specific numbers should be listed on the unit, in the manual, or can be found online. Your Inverter needs to be rated for the Wattage shown as well as that of any other 120v appliances you'll be using at the same time. - See the Solar 101 Tutorial or Solar Cheat Sheet for details.
The Amperage will tell you how long you can run the unit based on your Battery Capacity. - Bear in mind that it takes 150 amps of 12v Battery to create 15 amps of 120v alternating current. Something that uses 15 Amps at 120v will need 150 amp hours of Battery for each hour of use. - It will actually use a little more due to efficiency loss, and any other items running.
Important Note: Different types of Batteries will handle different levels of Discharge (50% for Lead Acid), so adjust the numbers up. You don't want to run your batteries “dry”. See the Solar Page for details. - It's also worth noting that a typical AC Unit doesn't use the same amount of Power all the time. The simple explanation is that it uses more or less Power depending on how hard it has to “work” to reach or maintain the desired temperature. The numbers below are based on manufacturer specifications, typically on the Low-Side of actual application.
Bear in mind that if you use 100 amp hours of battery tonight you'll need to replace 100 amp hours tomorrow (re-charge), which you can't do if you're using all of your Solar to run the A/C. - The following chart lists estimated Power use for common types of Van, Skoolie, and RV A/C Units as well as minimal Solar needs to effectively run them.
*There are, of course, many, many variables to consider (time running, available sun, ambient temperature, size, battery condition, etc., etc.) The chart below is intended simply to give you a rough idea.
As you can see from the Chart, running Air Conditioning completely on Solar Power will require a large expansion to your Solar Setup. You'll need several more Panels (which also means a bigger Charge Controller), a larger Inverter, and quite a bit more Battery Capacity than you will use for everything else in your daily life, combined.
Tech Tip: Remember, you won’t typically get 1200 watts from a 1200w Solar Array. You’ll come in under capacity, even on a sunny day. Use the numbers above to Start Small with your initial setup. You will almost certainly have to Scale up, if you intend to run A/C on Solar on a regular basis.
Should I run Air Conditioning on Solar Power?: - You can certainly go that route, and many do, but in our opinion, the additional cost simply isn’t worth it. - If you're willing to Rethink the way you use Air Conditioning, you can save a bundle on your initial Build and still beat the heat.
In addition to the points in our 10 Tips to Save Power Tutorial, I'd like to point out that as I write this blog it is sunny and 97 degrees. My wife and I are working, 3 feet apart, and our Air Conditioner is Not Running, but we are still quite comfortable.
Our Roof Vents are open and the Maxx Air Fan is humming away. We've shaded the windows on the South side of the Rig, but all we are using to keep cool are a Small Fan and a Personal Air Cooler. - The total cost for both was around $65, and they’re powered by USB ports in our computers.
If we do decide to run the House A/C, I'll fire up the engine first and use the on-board Air Conditioning for 15 minutes or so to bring the temp down. The Generator will be running when we flip the switch, and we'll use it to supplement as we monitor the Batteries until bed time. (As a common courtesy, we don’t run the Generator over night.) - A few hours after dark it will probably be enough to open a few windows and use 12v fans while we sleep.
There are many ways to limit the use of House A/C. - We spend Summers in the Northwest, and typically only see temperatures like this for a week or two out of the year. - You can stick to the coast, head for the mountains, or get a gig as a Camp Host for the Summer with free hook ups. - We've known several people who carry add-on Portable Solar Panels so that they can park the bus in the shade and string the Panels out into the sun.
Ultimately, you don't need to spend thousands more on a huge Solar Setup to run A/C. - You can if you like, but you have options.
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