Zero Degree Tested and approved for full-time RVing, Montana is the perfect luxury fifth wheel for extended stay camping.  In addition to its many luxury appointments and carefully thought-out floorplans, this quality coach is built like no other fifth wheel on the market.  Any wonder Montana has been the #1 selling luxury fifth wheel for 14 consecutive years?

In order to meet the high standards owners of the luxury Keystone Montana have come expect, the coach was subjected to testing in the Dometic extreme weather chamber in LaGrange, Indiana.

Keystone engineers consulted with Dometic to develop and conduct a test of a production model Montana to determine the capabilities during extreme cold weather conditions.

Dometic technicians placed the fifth wheel inside their controlled environmental test chamber and set the Montana’s thermostat to 74-degrees. The technicians then reduced the ambient temperature inside the test chamber to 0-degrees Fahrenheit over a sustained period of time designed to simulate a typical extreme cold weather camping trip. Test protocol required that temperature thermocouples be placed at multiple locations inside the RV interior and inside critical areas such as the Waterworks utility center, the pass thru storage, and adjacent to the holding tanks. These probes monitored and recorded temperatures as the test chamber was reduced to the target temperature of 0-degrees Fahrenheit.

Results of the test show that the production model Montana exceeded all expectations. While the "outside" temperature dropped as low as minus 4-degrees Fahrenheit, temperatures in the living room remained at a comfortable 72-degree average, bedroom temperatures averaged 70-degrees and bathroom temperatures averaged 75-degrees.

All of the holding tanks, dump values and waterlines remained completely operational as recorded temperatures exceeded 45-degrees Fahrenheit in these critical areas thru-out the duration of the test.

In short, conditions inside the Montana test unit remained comfortable throughout the testing cycle and critical components remained operational. These results validate the cold-weather effectiveness of the Montana Four Seasons Living package and Zero-Degree Rated components.


Some of the many Montana Four Season Features—

Tested and Approved for 0 Degree Usage Since 2005


  1. (R-21) Insulated Main Floor
  2. (R-15) Insulated Slideout Floors
  3. (R-11) Insulated Double Layer Supported Fiberglass Sidewalls
  4. (R-38 Equivalent) Radiant Technology Insulated Roof
  5. 35,000 BTU Furnace with Auto Ignition
  6. High Capacity  3” x 14” Foam Core Straight Line Heat Duct System
  7. Fully Vented Attic System
  8. Enclosed, Insulated and Heated Underbelly
  9. Enclosed, Insulated and Heated Holding Tanks and Dump Valves
  10. In-Floor Water Lines Located Above Insulation
  11. 12v Electric Tank Heaters
  12. Heated Exterior Convenience Center and Heated City Water Low Point Drains
  13. Main Level 15k BTU Free Flow Air Conditioning
  14. Wire and Frame for Ducted 2nd A/C with Remote Sensor and Dual Thermostat


For photos, floorplans, features, and dealer directory of the Montana visit the Montana website.

For Limited Warranty details reference the Keystone Owners Manual.