Located high in the Rocky Mountains — at an elevation of 10,200 ft. — this greenhouses experiences outdoor winter lows down to -20F. Despite the harsh conditions, the greenhouse is heated and cooled year-round by renewable energy systems to create a net-zero energy greenhouse that grows fresh citrus and avocados. It uses an innovative custom design developed by Ceres. The greenhouse incorporates light shelves / insulating shutters which close over the windows at night. The light shelves reflect light inside the greenhouse during the day, allowing for a high-light environment. With this modification, the roof is completely insulated with R-42 Structurally Insulated Panels. Powered off the home’s solar PV system, the energy-efficient and passive solar design enables a completely off-grid greenhouse (though the home’s solar panel system is connected to the grid). In a climate where fresh does not exist the winter months (all produce must be trucked in), the greenhouse provides the owners with fresh citrus, vanilla, avocados and fruits and vegetables, year-round.