A Passive Straw Bale Cabin – By Manuel Molles

Reader Contribution by Bruce Mcelmurray
article image

One of the great benefits of writing a blog for Mother Earth News is the people you meet along the way.  Manuel contacted me through Mother Earth News early in my blogging efforts.   As it turns out he and his wife Mary Ann only live a few miles from where we do.  I have found that those who read, work for, and contribute to Mother Earth News are a special class of people whom are friendly, sharing, and just good people to know.  I asked Manuel if he would take time from his 80 hour working week to tell about his straw bale construction cabin.  He generously accepted and I believe you will find his article highly informative and useful.  This it the first of a two part series on those who read and contribute to Mother Earth News.  It is a rewarding experience to be associated with this wonderful magazine.  Now the article from Manual: 

Our cabin in southern Colorado sits at the confluence of three drainage basins that support intermittent stream flow during spring snow melt. At an elevation of 8,200 feet, the cabin is exposed to plenty of winter weather, with annual snowfalls ranging to well over 20 feet. Low temperatures in winter are generally in the 20s or high teens, dropping occasionally to well below zero. For example, on February 2, 2011, our weather station recorded a low temperature of -22 °F outside the cabin. Summer temperatures are mild, generally no higher than the mid to low 80s with occasional excursions into the mid 90s. Since the local humidity is generally below 30%, even the highest temperatures are comfortable here. When summer thunderstorms hit, however, the outside temperature will dip quickly into the high 50s.

In the face of this climatic variability, the cabin is easy to maintain at comfortable temperatures with little energy expenditure. The main feature making the cabin energy efficient is its straw bale construction. The cabin was constructed about 20 years ago. It has a pitched metal roof, is a single story, and covers approximately 1200 square feet. The plastered, straw bale walls are 20 inches thick and the attic is well insulated with blown-in insulation. All windows are double paned. Large east-facing windows catch the morning sun in winter and the cabin’s brick floors do a good job of storing this heat. The roof eaves greatly reduce solar heating of the brick floor when the sun is high in the summer sky. No cooling is necessary in summer, even during the warmest days. When summer temperatures rise into the low 90s, inside temperatures remain in the 70s. We use a small wood stove to heat the cabin during the six colder months. Other than the passive solar heating from the east-facing windows, the wood stove is the cabin’s only source of heat and it goes out shortly after we go to bed. However, even on the coldest winter nights, with temperatures falling below zero, the temperature inside the cabin will be in the low 60s in the morning, after no heat from the wood stove for eight hours. The brick floors never feel cold on winter mornings and the wood fire soon has inside temperatures up to the low 70s. The insulating properties of our straw bale cabin still impress us after many years of facing winter blizzards and summer heat.

For more on Bruce and Carol McElmurray and our lifestyle and our friends go to:http://www.brucecarolcabin.blogspot.com