7 Tips for Adding a 2nd Air Conditioner to your RV or Camper

Have you checked the weather lately?

I hope so, because most of the United States is in for a heatwave. It will start this weekend and continue past the Fourth of July. While that’s awesome for your Independence Day plans, it’s not so awesome if you’re spending your summer aboard your RV or camper.

Everyone knows how uncomfortable it can be to climb into a car when the sun has been baking it for hours. You have to air out everything before you can even bear to sit down. The air conditioner can only do so much, even when it’s on full blast.

Your RV air conditioner is a much larger and stronger unit, but even its cooling capacity is limited. When you abuse your AC like you’re wont to do on hotter days, it strains and chugs. As the unit works harder, it may not cool the vehicle’s interior as efficiently. That can lead to some pretty sticky days and sweaty nights.

You probably haven’t had to rely too heavily on your air conditioner yet this summer. The hot days we’ve had have been punctuated with unseasonable coldness and chilly rains. Now that it’s warming up for the foreseeable future, though, you might wonder what options you have to stay cool.

Adding a second air conditioner is one of them.

Getting another AC unit is not as easy and buying it, hooking it up, and turning it on. There are a lot of considerations that must be made before you start shopping.

1. You Have to Double the Price…And Not Just for the Unit

Let’s start with a major consideration for any purchase. That’s the price.

The good news is that RV air conditioning units aren’t inherently expensive. This does depend on the make and model you choose.

Here are a few sample prices I found by doing a quick Google search:

• A Dometic Duo Therm Brisk Air2 air conditioning roof unit with 13.5 BTUs cost about $500
• A Red Dot On-Road/Off-Road rooftop air conditioner that runs on 12 volts of DC power is far costlier at $1,546.39
• Atwood’s Air Command non-ducted AC roof unit with heat pump retails for about $600
• Dometic’s Duo-Therm Brisk 2 air conditioner with 15,000 BTUs costs $470.99
• Coleman’s rooftop air conditioner, also with 15,000 BTUs, is about $600

As you can see from the above, you’re going to pay on average about $500 to $600 for a second air conditioning unit.

Even once you buy your AC, there’s still more money you’ll have to dole out. Installation is one such cost. You’ll probably want to hire an electrician for accurate and safe installation rather than risk doing it yourself.

Then there’s the energy load, which will be costly as well…

2. Be Prepared for a Much Heftier Energy Load

When it comes to appliances and items that suck up a lot of electricity, your air conditioner is towards the top of the list. What do you think happens when you add a second AC unit? The energy load goes up considerably.

The average air conditioning unit is powered at 15 amps and up (with 30 amps standard for RV air conditioners) and somewhere between 115 to 220 volts. These air conditioners are about 15,000 British thermal units (BTUs) or lower.

If you’re using two air conditioners onboard your RV at the same time, you’ll need an amp circuit. While a 30-amp circuit sometimes suffices, more than likely, you’ll need a 50-amp circuit instead. This is true if your air conditioners are especially big. Also, if you have an older RV or trailer, you’ll have to forget about the 30-amp circuit altogether. Your vehicle won’t be able to support both air conditioners on such little amperage.

If you absolutely must use a 30-amp circuit on a newer vehicle, then you’ll probably only be able to have on one air conditioner at any given time. You’ll have to switch between the two to cool the entire RV. Is this convenient? No. Does it prevent the system from overloading? Yes.

Speaking of overloading the system, if you have both units on and running at once, forget about using anything else that takes up too much electricity. I’m talking electric water heaters, toaster ovens, hairdryers, and microwaves.

The newer your RV is, the better the chances that a lot of the features are designed to be more energy-efficient. That often includes the air conditioner. If your vehicle has an energy management system, this is the time to make use of it.

The energy management system may include a control panel that tracks charger output, RV battery capacity, fault, low battery, whether your inverter is running, and air conditioner energy levels. If your dual ACs are starting to suck up too much power, you’ll quickly be able to see that and do something about it.

3. The Choice Between Ducted vs. Non-Ducted ACs Isn’t Always Yours

If you noticed before on that list of air conditioner prices I shared, one of them was non-ducted (the Atwood). What does that mean?

There are both ducted and non-ducted air conditioning units. Both have their advantages, but you should only select one. Which one isn’t always up to you.

First, there’s ducted air conditioners. This means that, throughout a room, there will be sheet metal ducts. Cold air passes through these ducts and out the vents. That’s how you stay nice and cool during your adventures.

Ductless air conditioners, then, are the opposite. With no ducts, they have blowers, which are boxlike in design. These blowers are situated throughout the room to keep air moving. They are typically situated on the ceilings or walls.

You’ll typically find ductless air conditioners on trailers and RVs due to convenience. If you do have a ductless system, you have to be especially careful about humidity. Ducted air conditioners dispel humidity more efficiently. Remember that humidity makes an ideal environment for mold to grow. Your bathroom and kitchen vents must be regularly cleaned and aired out to keep humidity under control.

4. Neither Is Where to Place the Second Air Conditioning Unit

Once you’ve gotten the cost and energy considerations out of the way, you have to figure out where this second air conditioner is going to go. Some people opt for a vent in the bedroom or other rooms of the RV. You should not take away a kitchen or bathroom vent for a second air conditioner. Those two rooms are where humidity accumulates most, so the vents are necessary.

Another spot many RVers choose for a second air conditioner is the roof of their vehicle. This is only viable if your first air conditioner is not on the roof. If it is, it’s not wise to install both vehicles there. First, your RV probably doesn’t have the wiring for dual roof RVs. Second, it can throw off the weight and balance of the vehicle (which I’ll talk about very shortly).

How do you choose which spot to house your second AC unit? For the cheapest and easiest installation, go where the wires are. If these are in the ceiling, then it makes sense to attach a second unit in place of one of the spare vents in the bedroom or living quarters.

5. You Gotta Know How to Balance the Extra Weight

The average weight of an air conditioner is roughly 40 to 120 pounds. Now double that for the weight of your second air conditioning unit. That’s at least 80 pounds on the lesser end and almost 250 pounds on the higher end. The latter may be equivalent to the weight of a whole adult passenger.

Weight distribution is necessary whether you’re driving an RV or towing a trailer. It’s somewhat more crucial in the latter situation if you want to avoid trailer swaying. That’s where your trailer dangerously swings out of control.

You could also cause damage to the front or rear axles by pushing too much weight to either end of the vehicle. That would be a costly replacement to have to make.

To ensure you’re in the clear before you take off, you might want to weigh your vehicle with both air conditioners onboard. You also want to include all your planned passengers, gear, equipment, fluids…the whole shebang. Then check this weight against the Gross Vehicle Weight Rating or GVWR. Your vehicle weight should not surpass the GVWR.

If you’re towing a trailer, then the Gross Combined Vehicle Weight Rating or GCVWR comes into play. This is the total weight of your trailer and tow vehicle. Again, you don’t want to exceed this.

You also have to know the tongue weight of your trailer setup, or the amount of downward pressure that can be applied to your trailer’s hitch. It should be less than the Gross Trailer Weight within a range of nine to 15 percent. This will help you avoid jackknifing and experiencing trailer sway.

6. You Must Watch Your RV Battery Like a Hawk

Whether it’s an RV or a trailer, your vehicle has a battery. If it helps, you can liken this to a smartphone battery. The more you use your phone, the more the battery drains, right? There are certain apps, like games or maps, that lower the battery more quickly than others.

It’s the same with your RV. Using the electricity in your vehicle will gradually deplete the battery, but some items will speed up the process. These are the aforementioned heavy-duty appliances and household items like microwaves and blow dryers.

RV batteries are fitted in their own bank, which typically includes at least two batteries but sometimes more. A 12-volt system is necessary if you often use things like lights, water pumps, televisions, air compressors, laptops, and smartphone chargers in your RV. There are 120-volt systems as well, which may be worth looking into for heavier power loads.

It’s easy enough to significantly drain your battery with just a single air conditioner. Once you add a second one to the fold, the battery levels can deplete even faster. That’s why you’re going to have to be incredibly diligent about tracking battery levels.

If you remember from my guide on RV batteries, then you know you must charge them once they reach 50 percent. Instead of a percentage, sometimes you have to go by the voltage number. A voltage of 12.20 is the equivalent of 50 percent for most batteries.

While the average RV battery can last three to five years depending on climate, you may have to replace yours more often. To keep your batteries for as long as you can,  store them carefully in the off-season, charging them when they drop to 80 percent instead of 50 percent.

7. Don’t Forget Shore Power and Other Accommodations

What do you do if you’re staying at a campground or park site for the night or the weekend? To link up to a 120-volt source of shore power, you’d use your 30-amp plug most of the time. Do you need a 50-amp plug if you’re running two air conditioners? More than likely, yes.

Some RV owners have used a generator to run their AC unit instead of risking sucking up too much shore power. Others with this AC-heavy setup have found that shore power amounts are typically only often enough to power a single air conditioner at a time, not both. That’s because shore power may be capped. In some instances, it’s 3,600 watts, but it may be more and sometimes even less.

This cap exists because your RV or trailer isn’t the only one on the whole campground. Others who are staying at the park need to rely on that shower power, too. If you hog up almost all power that’s available, that’s less for everyone else to use. There’s also a risk of you blowing the shore power breakers if you and other RVers are sucking up too much power at once.

If you do opt to exclusively use your generator for your dual AC units, then be prepared for a lot of noise. The generator is going to be running at full blast or close to it, so it’s going to be chugging, vibrating, and generally being loud. It may also give off an unpleasant smell. It’s possible that fellow campers might complain about your generator. To avoid this, try not to run the generator overnight so it doesn’t interrupt anyone’s sleep.

There’s another alternative, but it’s not the most conducive to day-to-day living. To avoid overusing shore power, you can unplug your microwave, RV battery charger, electric water heater, refrigerator, and other heavy-duty appliances. As I said, this is not a very comfortable way to live at all, but at least you’ll be cool.

Conclusion

It’s about 94 degrees Fahrenheit as of this writing, and it’s only going to be hotter in the days to come. If you plan on spending your Fourth of July or other summer holidays in your RV, you might wonder if a second air conditioner is worth it.

While you can certainly get one for your RV or camper, there are a lot of considerations to keep in mind. The energy load that the second AC unit requires is among your biggest concerns. If you’re using shore power, you might have to live minimally or use a generator to power both air conditioners at once.

Another major consideration is where you’ll place the second AC unit. It may go on your roof or in a bedroom or living room vent, but you’ll have to choose one. Once you figure all that out, you have to be extra good to your RV battery. It’s going to be taking the brunt of having a second air conditioner, after all.

Whether you choose just a single AC unit or two this summer, stay cool out there!

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