At home, a refrigerator is a very easy thing to understand. You plug it in, and it keeps your food cold.
But in an Airstream, there's a bit more you need to know if you want to reliably reach for fresh eggs and frozen ice cream.
Long ago, gas fridges ruled the earth
Those fridges were incredibly reliable and long-lasting. You can still find them in vintage trailers from the 1950s and 1960s, working just fine. They also didn't need any electricity at all—just propane gas—so they were great for camping away from hookups.
They had other benefits as well. Gas fridges don't have compressors like your home refrigerator. Through the magic of chemistry, they manage to start with a heat source (burning gas) and use it to create cold. It's blissfully silent and extremely efficient. A tank of propane can run a gas fridge for weeks.
The problem with the gas-only refrigerators was (and still is) that they aren't very good at regulating the temperature, so it's common to accidentally freeze your lettuce and still have soupy ice cream.
Modern fridges always need 12 volt power
Later the RV industry started using smarter gas refrigerators controlled by electronic circuit boards. This meant that they worked better at maintaining temperature and didn't need pilot lights, but it also meant that a connection to 12 volt electricity was required to power the circuit board. So the fridge started to sip some 12 volt DC power from the batteries. And that's been the rule ever since.
That's important to keep that in mind when boondocking, because the fridge is always going to be drawing some power from the batteries.
Two-way and three-way fridges
From the 1970s through 2021, Airstream mostly installed "2-way" refrigerators which offered the option to use a 120 volt AC electric heating element instead of burning propane gas. So when the Airstream was boondocking you could set the fridge to use propane, and when the Airstream was plugged in you could switch it to "AC" and save some propane.
But in either mode, the fridge won't run unless there's also 12 volt battery power available. That sometimes causes confusion for people. So to be clear: whether a 2-way fridge is using gas or shore power, it still has to have a little power from the batteries all the time.
To make things even more confusing, a few refrigerators are "3-way" meaning that they can cool using any of these methods:
- gas (plus 12 volt DC for the circuit board)
- 120 volt AC (plus 12 volt DC for the circuit board)
- 12 volt DC power alone
Our 2020 Globetrotter 23FB has such a refrigerator. Running it on 12 volt DC alone is a problem because it sucks a pair of batteries dry in just a few hours. (Ask us how we know.) Unless you have a large solar panel array to make up the difference, the 12 volt DC mode is not very useful when boondocking.
Now they're all electric
Starting in the 2022 model year Airstream switched to electric-only refrigerators with compressors. It's part of the inexorable move to all-electric RVs. Like all technology evolutions it comes with some advantages and disadvantages.
On the plus side:
- New electric compressor RV refrigerators are pretty efficient. They run on 12 volt DC, but don't kill the batteries nearly as quickly as the "12 volt DC" mode on a gas fridge.
- They cool down a lot faster. With a gas fridge you'd need to start it at least 8 hours before you leave on a trip, because they're really slow at cooling. An all-electric compressor fridge cools down in just a couple of hours.
- Electric refrigerators perform better on really hot days. A gas or gas-electric refrigerator depends on a flow of cool air in order to work efficiently. When the outside air gets above 90 degrees you might find the refrigerator getting uncomfortably warm inside. Electric compressor fridges are less affected.
- Finally, electric refrigerators avoid a major limitation of the gas models: they don't mind being operated off-level. Gas fridges are fussy about being level all the time, and if they're run while significantly off-level, they sometimes develop a case of terminal constipation and never cool again.
On the negative side:
- Electric fridges are yet another load for the batteries in your Airstream, and this really impacts your boondocking time. The power these fridges need will eat up most of your batteries in a weekend.
For this reason, it's more important than ever to have solar panels and/or higher-capacity lithium batteries installed.
Tips for giving your fridge a boost
To optimize its efficiency:
- When packing for a trip, help the fridge cool down by tossing a bag of ice or a few other frozen items in the freezer when you turn it on.
- Most new Airstreams have little fans built in to help the refrigerator cool itself, but if yours doesn't, there are aftermarket kits available. Not sure if your fridge has a fan? Open the outside refrigerator access door and scout around with a flashlight to find out.
- A full refrigerator will resist swings in temperature better than a half-empty one, so go long on food. If you don't want to carry a lot of food, at least put a few of those "blue ice" freezer packs in the freezer portion.
Finally, if you find your ice cream is too soft or your milk seems warm on a hot day, get one of those inexpensive wireless temperature sensors. Put a sensor in the fridge compartment and check the remote readout during hot weather. This may help you decide if a boost fan would be helpful (if your refrigerator didn't come with one) and you'll know if the interior is getting up to an unsafe temperature for food storage.