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Winterized again: I love my RV’s Webasto heater

| Updated Jan 22, 2013

I am a huge fan of the Webasto Dual Top RHA 100 diesel-powered combined air and water heater for the Roadtrek eTrek and, as an option, on other Roadtrek models.

In terms of heat, it both heats up the inside of the coach and provides hot domestic water. The entire unit fits under the vehicle chassis, saving precious space inside.  A small fuel line runs under the coach from the Mercedes engine up front to the Dual Top, mounted under the rear of the vehicle. Heat is pushed out through two air outlets. In my unit, they are directly beneath the rear sofa. When we make it into a bed, it's like having heated sheets. The domestic water boiler on the Dual Top is connected directly to the fresh water tank and the hot water faucets. And it is whisper quiet. Though mounted underneath the sleeping area on the underside of the coach, a muffler connects to an outside exhaust pipe and, really, we don't even hear it.

Here's a detailed description from Webasto on how the Dual Top works:

When the unit is switched on the dosing pump feeds fuel from the vehicle's fuel tank to the heater. Here the fuel is automatically ignited by means of a glow plug. If combustion does not occur immediately the unit automatically repeats the start-up procedure. In the combustion chamber a flame is lit which heats up the heat exchanger. The unit takes air in from outside of the vehicle for combustion purposes and the combusted exhaust air is discharged back outside. During heating, the integrated fan sucks in the air to be heated through the inlet and feeds it through the unit. As the air flows through the heat exchanger it is heated up and is then distributed through the outlet.

The connected hot air ducting spreads the air evenly throughout the vehicle interior. Due to the unit's separation of the combustion cycle from the heating cycle there is no quality impairment of the hot air. A temperature sensor constantly measures the interior temperature and adapts the heating level by automatically adjusting the amount of air passing through the unit. In this way, the temperature selected by the user is rapidly reached and maintained at a constant level. After the unit has been switched off, the combustion process is terminated in a controlled manner. For this purpose the unit briefly goes into re-run mode to cool itself down. It is then immediately ready for restarting.


iceI really came to appreciate the Dual Top on my return from sunny Florida to frigid Michigan. On the way back north, we overnighted near Lexington, KY in mid-January. The heater is quiet and kept us toasty warm at 70 degrees despite a plunging temperature outside.

I got worried the next morning when I saw ice caked on the underside of the heater. Oh oh, I thought.

Instead of a problem, it was a very cool feature (pun intended) of the heater. It was protecting itself against the cold. The Dual Top is automatically programmed to empty its water supply if the temperature drops lower than 43 degrees Fahrenheit. It does that, by the way, even if it is off. That night in Lexington, it got down to 26.

I had emptied the water from the fresh water tank and ran the inside faucets dry back in Georgia. But I still needed to get antifreeze into the eTrek. I stopped at one big RV dealer in Ohio and they weren't very interested in helping as they were unfamiliar with the eTrek.

So I drove home, where the thermometer dropped to three below zero overnight. I kept the Webasto heater running with forced air all night. The next day, I got it to my local Roadtrek dealer.

There, sure enough, we found the water pipes frozen. In a heated garage, we waited for them to defrost. I cranked the Webasto up to help further warm the interior and, after a couple hours, we were able to get antifreeze through the system. Fortunately, there were no leaks. If the heater hadn't kept the inside warm all night long, I'm sure those pipes would have burst.

As it was, it is a reminder not to take anything for granted with the weather. I should have winterized in Georgia.

But the incident has made me very appreciative of an excellent heater.

All said, though, I'd rather be in Florida.


Mike Wendland

Published on 2013-01-22

Mike Wendland is a multiple Emmy-award-winning Journalist, Podcaster, YouTuber, and Blogger, who has traveled with his wife, Jennifer, all over North America in an RV, sharing adventures and reviewing RV, Camping, Outdoor, Travel and Tech Gear for the past 12 years. They are leading industry experts in RV living and have written 18 travel books.

11 Responses to “Winterized again: I love my RV’s Webasto heater”

January 16, 2016at7:23 am, Epcot said:

I heard that Roadtrek is dropping the Webasto because of reliability problems

February 11, 2013at10:31 am, Mike Wendland said:

Oh yeah… the stove top…. let’s not talk about that “-)
Operator error.
Was using the wrong pan.

February 11, 2013at10:30 am, Mike Wendland said:

The Webasto heats the water that runs through the faucets in the galley and bath.
The instant hot has it’s own separate heater and tank and has switches to turn on (one for the tank pump and one for the instant hot heater).
The cold water is filtered… which means we don’t have to carry lots of bottled water anymore.
The instant hot is really instant. My wife loves it for hot chocolate and I use it to mix up my instant oatmeal in the morning.
There is no inverter switch. Just the battery switch… which I leave on all the time (except when parked for long stretches of time during inactivity).
Once I put water in the unit I flip on the two instant switches and leave on all the time.
There is very little that needs to be done.
My next trip is Wednesday as we head up to the Michigan Upper Peninsula for a dog sled race. Obviously, with temps around zero, I won’t be putting water in the tanks so those switches will stay off.
The Webasto will just do forced air heat on that trip. It runs on diesel. Running all night doesn’t even show a drop in the fuel gauge.

February 11, 2013at10:35 am, Randy Spencer said:

So the Instant hot is not 110v? it’s 12v? Do you know who makes the heater?

I have an inductive stove for my RV too. I found great cookware that nests for it:

Takes very little space.


February 11, 2013at10:05 am, Randy Spencer said:

Is the Webasto the unit that heats the RVs water? Does that include the instant hot water? The faucet appears to be from the InSinkErator people, but that runs on 110V. Is it really INSTANT hot water, or do you have to turn on the inverter to get it warming up?

I have LOTS of questions about the E-trex but there is no owner’s manual or list of components online. Did you figure out the inductive stove? Was it using aluminum instead of steel pans?


January 28, 2013at3:57 pm, Mike Wendland said:

It came standard on the eTrek. It runs on the diesel engine (minimum fuel consumption) and only causes a slight drain on batteries (for the fan intake). We ran it pretty much full tilt all night and then some. Didn;t drop battery charge by much at all. But, of course, with the eTrek, a full charge is just a few minutes away by starting the engine.

January 28, 2013at9:39 am, David W. Micklo said:

Mike, where did you get your Webasto and who installed it. Cost? Are there “authorized” installation dealers or just any RV repair shops? Does it use any electric? The biggest drawback of the RS propane heater is the use of the electric fan, really depletes your battery bank, makes boondocking in the cold tough. I would love a better solution. I don’t mind a good sleeping bag to stay warm, but I am with my three young boys; 9, 6 & 2 years old. Sounds like a great idea, if it’s truly just run off the diesel.

January 23, 2013at10:23 pm, Alex said:

Just drains all water and open all taps. That’s all…..
My rig sit 5th winter time in Ontario . I never ever had any problems

January 23, 2013at5:55 pm, Mike Wendland said:

That’s where it was… the traps. Fortunately, most of the water was out. But there was just enough that froze that we had to thaw to get the antifreeze through. I was very lucky nothing burst.

January 23, 2013at12:52 pm, Marlan at RV52 said:

Really nice article Mike. I’m living full-time in a 5th wheel in Texas – so winterization is pretty hard to do – we’ll run water and we have insulation on outside pipes. The fifth wheel itself has at least an enclosed underbelly – maybe protects for a few extra degrees AT BEST.

But I’m curious about one thing… If you drained your hot water heater and pipes, how much water was really left in your system anyway? I wouldn’t have thought there would be too much left to freeze, maybe in the traps?

Anyway, just a little curious.


January 22, 2013at5:46 pm, Gordon Hanebutt said:

Mike, Come on back Down!!!!!!!!!!

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