Old South residents have a saying: “The weather is close today.”
According to a New Orleans friend of mine, that means the temperature and humidity are jus’ ‘bout th’ same. Example: 92 degrees Fahrenheit, 91% humidity.
If the mention of muggy, stifling heat makes you reach for the nearest neck cooling pad, you’re not alone. Around June, many RV owners wonder, “What’s the most efficient RV air conditioner?”
But I have some bad news.
RV air conditioners don’t work like the air conditioner in your house.
If you’re lounging on your home couch, and you want to wear your favorite woven sweater in the middle of August (when it’s 97 degrees!), you just turn down your home air conditioner to 58 degrees and wait 30 minutes. Then enjoy your sweater weather and hot chocolate.
But on the same August day in your RV, you’ll be lucky to hit 80 with the A/C at full blast.
Why?
By the way, I wrote a condensed article on this topic that first appeared on RV with Tito. I encourage you to go check it out, especially if you’re considering a mini-split (and to read more of Brian’s excellent DIY RV content!)
Table of Contents
Why Would You Want an Efficient RV Rooftop Air Conditioner?
Why might you be interested in an energy-efficient RV air conditioner?
- Efficient air conditioners require smaller generators.
- High-efficiency air conditioners can be powered with smaller battery banks and smaller inverters.
- Power leftover to share with other loads and appliances.
And, of course, high-efficiency air conditioners are less wasteful. You’re doing your part to help the environment and reduce climate change, one watt at a time.
How to Can(‘t) Calculate RV Efficiency
Shopping for a window A/C for your home bedroom is easy; shopping for an RV A/C isn’t!
Every window A/C has an Energy Guide label with a SEER or EER number. The higher the number, the more efficient the A/C.
No such mandate exists for RV rooftops air conditioners. There’s no industry standard. Many manufacturers don’t even publish EER or SEER numbers. And most don’t even publish enough information to calculate it yourself. And while some manufacturers use ISO 5151 standard, it doesn’t apply to all RV A/Cs. We’re on our own.
There is no off-the-shelf method to compare the efficiency of RV air conditioners.
However, here are a few I found:
The General Electric 13.5k Rooftop A/C: EER of 5.9
I’d hazard a guess that most single-fan RV A/Cs have an EER between 5.0 and 6.5., so the GE A/C looks like the middle of the pack.
The Furrion 14.5k BTU Chill Rooftop A/C: EER of 7.97
The 2.13 EER posted on their website is wrong. I contacted Furrion to confirm.
Other companies, such as Coleman-Mach, did not respond to my request for EER test ratings.
Bonus Tip: Do (The Math) Yourself!
As I said, you probably can’t calculate EER yourself. You need to know the actual system (not nominal) cooling BTUs and input wattage at ARI standard test conditions, and good luck tracking that data down.
But you can kinda-sort-guestimate relative efficiency.
I’ve found the best hack to compare efficiency is this:
- Compare air conditioners with the same cooling BTU rating (e.g. 11k, 13.5k, 15k).
- Find the running watts at the same test conditions.
- You probably won’t know which test the manufacturer used, but at least make sure the ratings are given for similar conditions (e.g. ARI standard test conditions).
- Do not try to use Compressor Rated Load Amps (CRLA) as a substitute!
- Calculate the percentage difference between those running watts.
And that’s your hack. It’s most useful when comparing rooftop A/C ratings from the same manufacturer.
4 Energy-Efficient RV Air Conditioners
The major manufacturers all offer “high-performance” or “high-efficiency” A/C models. Dometic sells Penguin and Brisk High Efficiency models; Coleman-Mach has their Power-Saver series; Furrion has the Chill.
How efficient are they? As a rule of thumb, assume about 25-30%.
Now, what exactly does that mean?
- Does that mean your rig will get 25% colder?
- Does that mean it will cool down 25% faster?
- Does that mean cooling performance will stay exactly the same but draw 25% less power?
I can’t tell you. Your mileage will vary. Completely depends on what you’re replacing and how your RV was built.
Here are my top four picks!
Less Power Draw
If you’re pleased with your A/C performance but want to consume less power, check out these models.
1. Dometic Penguin II High Efficiency
The Dometic Penguin is one of the most popular low-profile rooftop air conditioners on the market. It still uses a single-fan design, but Dometic splurged on an upgraded compressor. It’s not the most efficient air conditioner on this list, but if you’re shopping for an ultra-low profile A/C, your choices are limited.
2. Coleman-Mach Mach 3 PowerSaver
Coleman-Mach (owned by Airxcel) doesn’t provide EER numbers, but it does provide running watts at standard and desert test conditions. Their Mach 3 PowerSaver is a whopping 55 percent more efficient than the Mach 3 Plus Signature Series!
More Cooling Power
If you’re looking for supercharged cooling power for under 15A, check out these models.
1. Furrion Chill
Available as a 14.5k and 15.5k air conditioner, the Furrion Chill uses a dual-fan design to increase cooling airflow. The Chill claims to be 25% more efficient than competing single-fan models and up to 40% more efficient than other A/Cs.
2. Dometic Atwood AirCommand
Similar to the Furrion Chill, the AirCommand uses a dual-motor design. Atwood claims it’s equivalent to a regular 16k BTU A/C – not bad! Bonus: Customers praise the AirCommand for its quiet operation.
5 Tips to Get Out of Your RV A/C
I’m using the term “efficiency” rather broadly. Yes, I’ll show you how to pick the most energy-efficient air conditioner off the shelf. But I also want to show you how to extract the most efficiency from any system!
1. Clean and Inspect Your RV A/C
No air conditioner can survive benign neglect. So remember your chores, and clean out that air filter! Follow your manufacturer’s instructions – Dometic says to wash and dry the air filter every two weeks of operation!
Use a fin comb to straighten out any bent fins. Ensure no leaves, debris or dead birds are clogging the shroud vents.
2. Use an A/C Soft-Start
Some air conditioners come with a soft-start straight from the OEM. If not, you can purchase a SoftStart aftermarket. These nifty electrical devices reduce the A/C startup power demand by 50-75 percent! You can use a smaller generator and bid goodbye to tripped circuit breakers.
3. Size the A/C for Your RV Space
An RV air conditioner should cool the return air (from the RV interior) by 18-20 degrees. Your living space should cool down 15-20 degrees, compared to the ambient air, within 20 minutes.
Too small, and the air conditioner won’t keep up with the heat gain. You’ll shorten its lifespan, and you won’t ever cool down!
Too big, and the air conditioner will quickly cycle off and on. This is called “short cycling” and is a good way to burn out your compressor. The rule of thumb is 1,000 BTUs per length of RV.
4. Park Out of the Sun!
RV roofs, especially when dirty, don’t reflect the heat well. The ceiling of your RV can be 5-20 degrees warmer than the floor or sidewalls!
Do yourself (and your A/C) a favor and park in the shade!
5. Insulate Your RV Windows
A high-efficiency air conditioner can cost thousands of dollars. You know what doesn’t? Foam board, sunshades, foam seal, soap and bubble wrap.
- Wash a white TPO or EPDM roof to reduce solar heat gain.
- Install sunshades or reflectix covers (with stick-on velcro) in windows and below ceiling fans.
- Use D-bulb foam seal around doors and window frames to eliminate seam drafts. Use canned spray foam around underbelly penetrations and fender wheel openings.
- Screw foam board to the underside of your floor, or install skirting around the base of your motorhome or fifth wheel.
