Saturday, December 9, 2023


Keep temps under control digitally

By Greg Illes

When we first traveled in cool weather in our RV, we luxuriated in the coziness of the cabin heater. After decades of tent camping, we literally basked in a 70° F coach while gazing contentedly through the windows at the chilly world outside.

But our satisfaction was periodically interrupted. The cabin would come up to heat, the heater would shut off, and then the cabin would begin to cool down. And cool down some more. Eventually, when it got down to around 65° F or so, the heater would kick back in. So we’d find ourselves with oscillating periods of comfort and chilliness. On some really cold nights, this would happen about every 15 minutes or so. (We don’t use air conditioning much, but the problem is the same there, as well.)

The culprit was discovered: an old-tech, mechanical bi-metal thermostat. These dinosaurs need a big temperature swing to mechanically trip the switch on or off. Researching turned up a bevy of digital-style thermostats which are sensitive to only one or two degrees of temperature change.

Not just any old digital thermostat will necessarily work. Different systems have different requirements, depending on how the heater and A/C are powered and controlled. Choices include programmability or simple manual settings. Our 2003 Itasca unit needed to be battery-powered but we didn’t need programmability. We found a wiring diagram of the heater and air conditioner control circuitry online at Winnebago, showing us the correct control wires needed for hookup. The actual installation was quite simple.

Fan speed was an issue. Our coach has a two-speed capability, but most thermostats have only one. The choice was hard-wiring to only one speed, or adding a two-way switch (SPDT) to preserve the option. After experimenting with sound, efficiency, and battery drain, we found we preferred the LOW fan speed setting. It’s now hard-wired.

While the new thermostat fit where the old one did, we opted to install a new base panel, made out of textured ABS. This stuff is wonderfully easy to work with, and it makes for a really professional, modern appearance as well.

Cold winter nights are now more enjoyable than ever, and our cabin temp stays within a couple of degrees of where we set it. Brings a real smile to our faces as the wind howls around us.

Greg Illes is a retired systems engineer who loves thinking up RV upgrades and modifications. When he’s not working on his motorhome, he’s traveling in it. You can follow his blog at



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