Angled to catch maximum sunlight during winter, the dark-painted sloped roof absorbs solar heat throughout the day while funneling rainwater away from the front door.

+-------------------------------------------------------------+
|              SLANTED-ROOF SOLAR HEAT TRAP                   |
|                                                             |
|     +-----------------------------------------+             |
|     | HIGH REAR WALL                           \            |
|     | [ Mylar Heat-Reflective Lining Inside ]   \ [ ROOF ]  |
|     |                                            \          |
|     +--------------------+------------------------+         |
|     | LOW FRONT WALL     | [ 6-INCH ENTRY HOLE ]  |         |
|     +--------------------+------------------------+         |
+-------------------------------------------------------------+

How to Build

  1. Cut the side panels of a rectangular box at a 20-degree incline from back to front.
  2. Wrap the top roof panel in black plastic trash bags or spray-paint it matte black to absorb sunlight.
  3. Line the interior with heat-reflective foil and pack the bottom with fresh straw.