Since January 4th, the service department has been testing my vehicle nearly every day to figure out why the heat never reaches the target temperature. We finally had some consistently cold weather and after a full day of testing the dealership conceded that there is indeed something not working properly when the temperature in the cabin reached only 40º after running an entire evening and overnight.

Then, I received a hopeful call from the dealership owner who had stepped in to help resolve these issues telling me that they had some success in getting the heat up in the cabin. It involves the valve in the heat exchanger.

Under the front passenger seat is the heat exchanger that is installed as part of the Alde system. The heat exchanger is supposed to allow heat to transfer from an engine loop to the cabin’s loop when driving to utilize that otherwise wasted engine heat to warm you up while you travel, and it can also use an included separate pump to transfer heat from the cabin system to the engine to warm up the motor before heading out on a cold day.

Typically, to heat the cabin using the Alde, you simply turn on the system with propane and/or electricity and it circulates heated glycol through radiators in the perimeter walls and in-floor radiant panels. While driving, you have the option to heat the cabin without using propane or electricity. You instead use the heat generated by the engine by turning on just the pump portion of the Alde – the heat from the engine is transferred to the circulating cabin system through the heat exchanger. This is an enticing selling feature – heat without wasting propane or electricity using heat you’re generating anyway just by driving around (hopefully to more exotic places than your dealership).

To warm the engine when you’re camping out in the cold, you can turn on the Alde as usual with propane or electricity, and turn on an additional pump located at the heat exchanger under the passenger seat which circulates fluid through the engine block. Heat from the cabin loop transfers through the heat exchanger to the circulating fluid in the engine loop which warms the engine and helps you avoid cold starts when it’s frosty outside and time to move camp.

Now, this heat exchanger includes a valve. According to an employee of Roadtrek, as well as other more knowledgable Roadtrek Owners courtesy of the Facebook group, the valve is left open except in cases where you don’t want heat from outside to transfer in, like in very hot summer days where the heat from the engine might give your passenger a hot seat. There would be little heat loss from the cabin loop through the heat exchanger as long as you don’t engage that second pump for the engine loop.

That brings me back to the call from the dealership – they closed that valve and the heat started performing almost 20º better. Even at its peak performance however, the largest rise in temperature has been 50º after running an entire evening and overnight, so when it’s 0º outside, you can only expect to get to 50º in the cabin using the heating system. I say this is what you can expect because no one, not Roadtrek or Alde, will tell you what performance to expect from the system. They won’t even give ballpark numbers other than to say you will be warm in the cold weather.

It doesn’t make sense that simply turning a valve that the manufacturer and those who better understand the system say should not affect performance would produce that much difference in temperature.