Air, antifreeze, batteries, mice—and the decisions to make before you put your trailer to bed for winter.
Every fall, conversations about winterizing Airstreams seem to turn into debates.
You have to blow out the lines. No, you have to use antifreeze.
Never put antifreeze through the water heater.
Take the batteries out. Leave the batteries in.
And don't even get people started on what supposedly keeps mice away.
The problem is that we sometimes confuse the method with the objective.
I've read all the blogs, posts, and manuals, and I've come to realize that the goal of winterization isn't to follow somebody else's ritual. It's to make sure there's nothing in your Airstream that winter can hurt.
There is more than one way to accomplish that, and Airstream itself documents both compressed-air and RV-antifreeze methods. In fact, the current Flying Cloud manual acknowledges that getting every bit of water out can be challenging and highly recommends adding non-toxic RV antifreeze if there is any doubt that the system has completely drained.
I use both.
Not because that's the only correct way to winterize an Airstream, but because it gives me the greatest margin for error.
Before You Start, Make a Few Decisions
Before I open a drain or pull out the air compressor, I think there are four things every owner needs to figure out:
- Will you use compressed air, RV antifreeze, or both?
- What kind of water heater do you have, and what does its manufacturer require?
- What will you do with your batteries during storage?
- Are you simply protecting the plumbing from freezing, or putting the entire trailer to bed until spring?
That last distinction matters. Winterizing the plumbing and preparing an Airstream for five months of storage are not the same job.
And before doing any of this, find the winterization section in the owner's manual for your year and model. Plumbing layouts, valve locations, water heaters, and battery systems have changed over the years.
This article is written primarily for traditional Airstream travel trailers. The same principles apply to Basecamp, but Basecamp has its own plumbing configuration and tank-heating systems, so I'd use this article to understand what you're trying to accomplish and the Basecamp manual to determine exactly how to accomplish it on that trailer.
Air, Antifreeze—or Both?
Compressed Air
With the air method, you first drain as much water as possible, then use a regulated air compressor and a blow-out adapter at the city-water connection to push the remaining water out of the plumbing.
Check your owner's manual for the maximum air pressure for your trailer. Many current Airstream travel-trailer manuals specify a maximum of 50 psi, and too much pressure can damage plumbing components.
Once you've finished gravity-draining the system, the idea is to give the compressed air somewhere to go—but only one outlet at a time. Close the low-point and other drain valves as appropriate for your trailer so the system can build pressure, connect the compressor at the city-water inlet (you may need a winterization adapter to do this), and then work methodically through the plumbing.
Open one fixture and let the air push the remaining water out until the sputtering stops and you're getting air rather than water. Then close that fixture and move to the next one. Do both the cold and hot sides of every faucet, and don't forget the shower, exterior shower, toilet, and any other water outlet on your trailer. Airstream notes that it may take opening and closing fixtures more than once to work trapped water out of low spots.
I like to work in a consistent order so I know I haven't skipped anything. You don't have to use my exact order; the point is to account for every branch of the plumbing system.
And don't forget the pieces that are easy to overlook. Depending on your model and procedure, that can include the water pump and strainer and the black-tank flush line. Airstream's winterization guidance specifically calls for clearing trapped water from the pump and blowing compressed air through the black-tank flush connection.
When you're finished, disconnect the compressor and continue with the rest of your winterization method. If you're using air only, this is the point where you're relying on having removed enough water from every vulnerable part of the system. If you're following it with antifreeze, as I do, you're adding another layer of protection against anything you may not have been able to see or completely clear.
RV Antifreeze
The other option is non-toxic RV antifreeze approved for potable-water systems (not automotive antifreeze).
Most modern Airstreams have a winterization connection near the water pump that lets the pump draw directly from the antifreeze container. You then run each hot and cold fixture until you're getting solid pink antifreeze.
This is also a perfectly legitimate winterization method.
Both
I drain everything, blow out the system, and then pump antifreeze through it.
Is that overkill?
Maybe.
But after blowing the lines out, it doesn't take much additional time to add antifreeze, and I like knowing that if a small amount of water remained somewhere I couldn't see, I've added another layer of protection.
Winter is not where I want to discover that I was almost thorough enough.
Water Heaters—You Need to Know What You Own
This is one place where generic winterization instructions can get people into trouble, because different Airstreams have used very different water-heating systems.
Traditional tank-style water heaters are normally drained, and when you use the antifreeze method the heater is typically bypassed so you aren't filling the entire tank with gallons of pink antifreeze. Airstream's general winterization instructions specifically call for putting the water-heater bypass valve into the bypass position before pumping antifreeze through the plumbing.
The Girard GSWH-2 tankless heater is different. Girard specifically allows either compressed air or non-toxic RV antifreeze for winterization and says a bypass kit isn't necessary. That means I do run antifreeze through the Girard in my trailer. Other brands of tankless heaters may be different, so consult your manual.
The Alde system used in Classics is different again. The freshwater in the Alde boiler must be drained when freezing is possible. The glycol in the Alde heating loop is a separate system and should not be confused with the pink RV antifreeze used in the potable-water plumbing. Follow the Classic and Alde manuals for the specific procedure.
This is why “I saw somebody do it on YouTube” isn't enough when it comes to a water heater.
Know which one you have.
Drain First—No Matter Which Method You Choose
Before I start with air or antifreeze, I get as much water out of the trailer as possible.
I empty and thoroughly rinse the black tank, empty the gray tank, and drain the fresh-water tank. I open the low-point drains and drain the water heater according to its instructions. I also remove or deal with water filters as required by the particular system.
If your Airstream has a black-tank flush (and most newer ones do), don't forget that there is water in that plumbing, too. Airstream's compressed-air procedure specifically calls for blowing compressed air through the exterior black-tank flush inlet to clear the remaining water.
That's going onto my checklist. It wasn't on the old one.
Then I work methodically through every water fixture: kitchen sink hot and cold, bathroom sink hot and cold, shower, toilet, exterior shower, low-point drains, and anything else connected to the water system.
This is one of those jobs where slow and systematic beats clever.
Don't Forget the Drains
Protecting the pressurized water lines is only half the plumbing job.
There's water sitting in the P-traps under the sinks and shower, too. After the water system is protected, I pour about a cup of RV antifreeze into the kitchen sink, bathroom sink, shower drain, and toilet so the traps and toilet seal aren't sitting full of plain water. Airstream also instructs owners to add RV antifreeze to the drains and toilet as part of winterization.
I also disconnect the shower heads and let them drain completely rather than trusting that the flexible hose hasn't trapped water somewhere.
Little pockets of trapped water are what we're trying to eliminate.
Then I Put the Inside to Bed
Once the plumbing is finished, winterization becomes winter storage.
I remove anything edible and anything that could freeze, leak, or burst. I clean the refrigerator thoroughly and leave the refrigerator and freezer doors propped open. I often use baking soda and crumpled newspaper as well, but the important part is that the refrigerator is clean, dry, and ventilated.
I remove small battery-powered devices that I don't want sitting unused all winter with batteries inside them, and I service the batteries in safety equipment such as the smoke detector rather than simply forgetting about them until spring.
I also tend to remove bedding, towels, and other soft goods. That's not required to keep the trailer from freezing; it's simply part of how I prepare mine for months of storage. It gives me confidence that nothing but me is nesting in my bed.
Which Brings Me to the Mice
If you ask ten Airstream owners how they keep mice out, you'll probably get fifteen answers.
I know because I think I've tried most of them.
Peppermint oil. Lavender oil. Dryer sheets. Fabric softener. Grandpa Gus's repellents. Some particularly impressive repellent packets I found at Can-Am RV. At various points my Airstream has probably smelled less like a trailer and more like an aggressively scented spa.
I still use repellents. I also use electronic repellers inside and underneath the Airstream.
But I no longer confuse those things with a rodent-prevention plan.
The fundamentals are much less exciting: remove the food, remove attractive nesting material where practical, look for entry points, seal what you can, and use traps. Mice can get through an opening about 1/4 inch wide and wreak havoc on your wiring. CDC guidance emphasizes sealing openings and using snap traps when rodents are present.
I tend to go overboard because I really, really don't want mice in my Airstream.
But after all my aromatic experiments, I've learned that sometimes it still comes down to good old-fashioned traps.
Batteries Deserve Their Own Decision
I'm deliberately not going to tell you there's one correct thing to do with your batteries over the winter.
There isn't.
Battery chemistry matters. Your Airstream model matters. Your charging system matters. Whether you have shore power available matters. And some newer Airstream lithium installations include battery heaters and systems that are very different from older removable lead-acid batteries.
Airstream's general guidance for many traditional trailers recommends removing removable batteries, storing them where they won't freeze, and keeping them charged. But some newer models are different: the current Trade Wind, for example, has internally heated lithium batteries and even states that battery removal should be performed by a qualified Airstream service technician.
I leave my lithium batteries installed, keep the trailer plugged in, and leave the battery-heater system configured for winter.
That's what makes sense for my equipment and storage situation. It isn't a blanket recommendation.
Check your Airstream manual and the recommendations from your battery manufacturer, and if you're unsure, talk with your dealer. Decide what you're doing with the batteries before you put the trailer away rather than remembering them halfway through January.
My Fall List Includes Things That Aren't Really Winterization
I also use winterization day as an excuse to knock out several maintenance jobs because I'm already working around the trailer.
I inspect the roof and exterior sealants. Airstream actually recommends inspecting exterior sealants twice a year, and fall is an easy time to remember it.
I lubricate things that need attention—door hardware, locks, steps, stabilizers, and appropriate window seals—according to the recommendations for those components. I protect the 7-way connection, cover the tires when the trailer will be sitting exposed, remove electronics and batteries I don't want stored in the trailer (batteries can corrode and cold can kill electronics), and give everything one last walk-around before I shut the propane off for storage.
Those things are simply good jobs to do once a year, and winterization gives me a reason to do them. I separate them on the checklist under Optional Fall Maintenance rather than pretending they're required winterization steps.
The Goal Isn't to Do It My Way
That's probably the biggest thing I want new owners to understand.
You don't have to winterize exactly the way I do.
You can use compressed air. You can use RV antifreeze. You can use both, as I do. Your water heater may require a different procedure than mine. Your battery plan may be completely different. And your personal mouse-prevention arsenal may contain fewer fragrances.
What matters is understanding why you're doing each step.
Water that can freeze needs to be removed or protected. Equipment that has its own winterization procedure needs to be handled according to that procedure. Batteries need an intentional storage plan. Food and anything that can freeze, leak, attract pests, or corrode should be dealt with before you walk away.
Once you understand those objectives, winterization stops feeling like a mysterious ritual and starts feeling like a system you can work through.
And that's really the point.
The goal of winterization isn't to follow somebody else's ritual. It's to make sure there's nothing in your Airstream that winter can hurt.
Want the steps without all the explanation? Download the free Riveted Advisor Airstream Winterization Checklist and work through it as you go.