Almost all RV air conditioners run off 120-volt AC electricity, which is what most campers call “shore power” or “grid power.” And as many RV owners learn to their dismay, you need to be plugged into a power pedestal or a generator to operate your air conditioner. Otherwise, misting fans it is!
But what if … there was a 12V RV air conditioner? What if there was an air conditioner that ran off your batteries, just like your water pump? What if you could – gasp – run your air conditioner off-grid and not pay $5,000 in lithium batteries and a 3000-watt inverter for the privilege?
It turns out … there are 12-volt RV air conditioners!
… But everything else I said is wrong.
Super-Short Introduction to How an RV Air Conditioner Works
The heart of any air conditioning system is a mechanical device called a compressor. It moves the refrigerant fluid from the evaporator to the condenser and back again, ad infinitum. The refrigerant absorbs heat from the inside and releases it to the outside, a process we know and love as cooling. Thank you, William Carrier.
For more information on RV air conditioners, visit my guide: Your Burning Questions to the RV Air Conditioner. For now, just remember this: Your A/C compressor makes everything else “go.”
The Hiccups and Hurdles of a Typical RV Air Conditioner
The compressor is a hungry little beast. It eats electricity, and most portable air conditioner compressors in the United States are designed to operate on 120V electricity, which, as we’ve learned, doesn’t come from batteries. It comes from the grid. Which is no help when boondocking at all.
To add insult to injury, most RV air conditioners are incredibly inefficient. They draw a LOT of current, usually 10-15 amps (13.5k BTU) or 14-18 amps (15k BTU) on High Cooling mode. You can upgrade to a more efficient RV air conditioner for dry camping, but be warned: You’ll still need to ante up the amps.
And … it gets worse. Because if you are boondocking or dry camping, then plugging in isn’t an option. So the next best choice is a generator or the motorhome engine, both of which are loud, smelly, and burn liquified dinosaur bodies. Not a good way to stealth camp, make friends, or save the earth.
What Are the Profits and Possibilities of a 12V RV Air Conditioner?
Now that you know the disadvantages of a typical RV air conditioner, what are the advantages of a 12V RV air conditioner?
(Check out my picture below of the mechanical innards of a not-yet-released 12V air conditioner. After I snapped the picture, the sales rep quietly dropped the housing back on. The intrigue, eh?)
No Inverter Losses
First, the inverter – or a lack of it. In theory, you can run an air conditioner off your house batteries using an inverter, which is a sort of magical black box that transforms “shore power” into “battery power.”
Unfortunately, inverter systems waste a lot of energy. You never get as much as you give. It’s not uncommon to lose 20, 30, even 40% of your total power! Yikes!
That’s part of the appeal of a 12-volt air conditioner for an RV: You could run the A/C directly from your batteries. No inverter losses! Hurray!
Low Power Draw
Many RVers are familiar with high-end refrigerators and freezers from Indel B, Furrion, Everchill, and Vitrifrigo. These 12V refrigerators are storming the RV industry, replacing the slow, clumsy absorption refrigerators of yesteryear.
So there’s this assumption that a 12V RV air conditioner would be the same sort of improvement. But is that assumption accurate?
Do 12-Volt RV Air Conditioners Exist?
Alright, I’ve dabbled in theory long enough.
Here’s the short answer: Yes, 12V air conditioners exist. Do they solve any of the problems I’ve described? No (not yet).
But let’s take a break from my regularly scheduled soapbox. Let’s take a look at some of the 12-volt air conditioners for RVs available in the US. Afterwards, I’ll revisit the problems with a 12V RV rooftop air conditioner.
- This list only contains self-contained rooftop air conditioners, not mini splits or under-bunk units like the Dometic CoolCat.
- This list only contains compressor-driven air conditioners, not evaporative swamp coolers like the Fresair.
- This list only contains 12V air conditioners, not 24V or 48V automobile air conditioners like the
- This list is not a review. I haven’t used most of these products, just oggled them at a dealer show.
Lastly, a bit of advice: Please remember that the advertisements usually show the maximum cooling capacity and the lowest amp draw – which never happen at the same time!
- Voltage: 12V
- Minimum Amperage: 18A (1000W) | 19A (2000W)
- BTU: 4,094 (1000W) | 6,824 (2000W)
- Weight: 50.2 (1000W) | 70.6 lbs (2000W)
- Opening Size: 18.9×15.3 in
- Noise: Unknown
- Price: ~$2,000 | ~$2,400
The Dometic RTX Series is available in the 1000W and 2000W sizes. Both are self-contained truck cab air conditioners. They are battery-powered with up to 12 hours of run time. They offer cooling only, no heating.
- Voltage: 12V
- Minimum Amperage: 22.5
- BTU: 12,000
- Weight: 59 lbs
- Opening Size: 14.6×20.25 in | 14×14 in
- Noise: 33 dB (minimum)
- Price: ~$2,600
The Mabru RVSC was designed specifically for campers, vans, and small RVs. With a little modification, it can fit inside a 14×14 opening. It draws between 22.6 and 54.4 amps at 12VDC with 3 Cooling Modes and 3 Fan Speeds.
- Voltage: 12V
- Minimum Amperage: 48
- BTU: 11,000
- Weight: 75 lbs
- Opening Size: Unknown
- Noise: 65 dB (maximum)
- Price: ~$2,800
I don’t know much about this air conditioner. It seems to be a competitor to the Dometic RTX 2000. It’s rated for up to 11,000 BTUs of cooling capacity, which is quite a bit for such a small unit. It does require an auxiliary battery to operate, though.
- Voltage: 12V/24V
- Minimum Amperage: 40-60A | 50-70A | 50-75A
- BTU: 5,456 BTU | 10,230 BTU | 11,253 BTU
- Weight: ~73 lbs | ~84 lbs
- Opening Size: 14×12 in | 14×14 in
- Noise: 28/38 dB (minimum)
- Price: ~$2,000 | ~$2,700
B-Cool is a well-known brand in the van life and truck camper space. You’ll find them in Mercedes Sprinter vans, small custom Class C RVs, and commercial vehicles like the Ram Promaster. The B-Cool brand is built by DC Power Solutions, originally founded in 2012.
Nomadic Cooling 3000
- Voltage: 12V
- Minimum Amperage: 35-55A (105A Max)
- BTU: 11,830
- Weight: ~61 lbs
- Opening Size: 14×14 in
- Noise: 60 db (maximum)
- Price: ~$5,350
As you can see, the Nomadic 3000 costs almost twice what some other 12V van air conditioners cost! That’s partially because it’s big … almost 12k BTU, almost as big as a regular RV air conditioner! And yet it still draws as little as 35A on ECO mode and Low fan. That’s pretty impressive. And it only weighs 61 lbs. As they say, you get what you pay for.
The Downsides and Disadvantages of a 12V RV Air Conditioner
If you thought the air conditioners themselves were expensive, just wait until you learn about the battery requirements!
Many RVs get by with a 100Ah or 200Ah battery, no more. And of that capacity, only half is usable with a lead-acid battery. Oh, that reminds me – most battery-powered A/C manufacturers will highly recommend you use lithium batteries, not lead-acid.
To even think about running a 12V air conditioner off your battery bank, you need at least 200Ah of usable capacity, minimum. That just might buy you one night’s sleep. Something like 400Ah is more reasonable, which is another $2,000 in lithium batteries.
Many 12V air conditioners don’t fit inside a standard 14×14 roof opening. The Dometic RTX requires a 15.3×18.9 opening; the
Two 12V air conditioners that can fit a standard 14×14 roof opening are the Mabru RVSC and the Nomadic Cooling units.
12V air conditioners require huge wires. That’s just the nature of 12V electricity. If I refer to this handy-dandy chart from Blue Systems …
… then the wire size for a 12V RV air conditioner (drawing 100 amps on High) positioned 50 feet away from the battery should be 3/0 AWG.
For reference, that’s about as wide as your pinky finger. It’s probably bigger than the main service wires to your entire house. Also for reference, Lowes charges $7 a foot for this stuff.
So, I can’t see 12V air conditioners becoming popular on 5th wheels and Class A’s anytime soon. The distances are just too great!
Are 12V RV Air Conditioners a Fad or the Future?
Did you know 12V air conditioners were invented for fleets, not RVs? In ye olden days, truck drivers would idle their engines for hours just to keep cool. Fleet owners realized this was wasting expensive fuel and wearing down the engines (plus idling is now illegal in many places), so they invested in standalone air conditioning systems. The drivers stayed cool; the engines stayed off. Everybody was happy.
Then #vanlifers got wise and adopted the same tech. Which makes sense because a small, efficient, lightweight, battery-powered air conditioner is a great choice for a living area not much bigger than a chicken coop (and no ducting required).
But are 12V air conditioners really the best choice for today’s blubbery RVs?
Here’s my opinion: What makes a 12V RV air conditioner so desirable … isn’t the 12V part at all!
It’s that most of these 12V air conditioners use variable-speed compressors, which are able to operate at different speeds. That’s why you can pull 20A on LOW or 80A on high – because the compressor is smart enough to slow down or speed up!
That’s also why they’re so much quieter – because of the quality of the compressor. They’re not repeatedly cycling and blasting your eardrums; they’re just humming quietly along at partial capacity.
I don’t know if 12V air conditioners will supplant 120V air conditioners, but I have no doubt that variable-speed compressors will eventually take over everything. The benefits are just too good. And with air conditioning consuming 6% of all electricity used in the United States, they just might save the earth, too.