Insulation, Heat, and A/C
Grand Design cut no corners when it came to insulating their M Series Toy Haulers. These trailers feature a thermal roof design that doesn’t just end with the roof, but extends down around the bottom of the front cap as well. Fiberglass insulation, a layer of radiant foil, and another similar radiant foil insulation barrier are used as the three layers that insulate the floor and garage. (Yes! The garage is insulated, a detail that most toy haulers lack.)
The sidewalls, ramp door, and slides are welded aluminum framed and laminated with rigid foam insulation, along with the baggage doors and even the gooseneck of the Fifth Wheel! Additionally the attic is vented to reduce condensation in the roof structure, and there is a Rail-Tite underbelly seal that helps to keep the corrugated barrier up tight against the frame and sealed from the elements.
There is 40,000 BTU of heating power to be delivered through the high performance furnace and fireplace. Dedicated heat ducts run to the underbelly and storage bay, as well as 12 volt heat pads on each holding tank to ensure functional water systems even in the coldest of temperatures.
If you are worried about the heat, no need. Grand Design uses a Stealth A/C System, which is 2x quieter than competition units. Airguide Technology is used to strategically guide and force air out of the vents, and the racetrack ducting ensures 23% more airflow than the average of leading competitors. There are 3 A/C units throughout the 381M to ensure that no matter where you are in the trailer you are never hot.