The curved walled cob sun room straw bale entrance to this hybrid home in the mountains of northern New Mexico. The large glass paneled windows provide a great deal of heat in this small room. The heat is collected in the dark blue earthen floor and soaked into the cob wall as well. The thermal mass of those highly dense earthen elements will not only soak up the heat but hold it for a long period of time. This is the beauty of the properties of thermal mass for any building, but which is often featured with natural buildings of many kinds.
The amount of glass to floor area ratio in this room is well above what is required for a normal passive solar designed house. But given the 8000 foot location of this home and the angle of the house which lets less sun in during the summer months when the room could get much too hot, the room works very well. The temperature variations at this altitude are much more severe than at a lower altitude. And the room was designed to collect and maintain as much sun as possible.