• There is no one eco-home that is better than any other- every green technology has its place and should be used where/how appropriate.  Earthships are one type of green tech.  Geodesic domes have their place, as do buried houses, as do shipping container homes.  There is no straightforward answer to "what is the best eco-home design?"
• The actual geological environment where you are building matters a lot.  How much rain does your site get? What about agricultural presence?  How hot are the summer time lows?
  
• It is always greener to retrofit than to build from scratch!

It gets really hot in the summer.
We had a few summers where interior temperatures were over 100.  Part of this is because we have less attic insulation than called for.  Another part of this, the bigger part, is that we live in southern Virginia and it is really bloody hot, and even more humid, in the summer.  The summer night-time lows are in the high 70's.  The classic earthship specifications are designed to function in desert climates: dry and with cool nights.  In retrospect, it would have been wise to face the house southeast or southwest.  But due south gives us way more solar gain (heat!) than we can handle.  We installed air conditioning three years into the project, and are still able to keep our monthly power consumption below 1,000 kWh.

Rainwater harvesting is not as easy to use at it looks.
The earthship books made rainwater harvesting sound simple.  It was not.  For rainwater to be potable, if you want to drink it, it must be treated.  Treatment includes filtration, aeration, and disinfection.  All that was complicated and expensive.  We switched to a shallow well for our potable water needs, and use rainwater for irrigation.   Read more about our water use here.

If you are considering rainwater harvesting, we strongly recommend Rainwater Collection for the Mechanically Challenged, a wonderful and honest book about how to create a viable rainwater harvesting system.

The greenhouse and planter require maintenance and knowledge to successfully operate.
Spider mites. Relative humidity.  Soil acidity.  These are just the basic concepts we had to become familiar with.  More than once, our entire greenhouse was decimated by critters, necesitating removal and disinfection of all the plants.  As it turns out, plants really like the sun.  A lot.  So much so that they grow aggresively towards it, which means that the plants grow right up to the glass and need to be regularly prunned.  The planter fill with roots, which alters the water flow in it, and as the planter matures the water use habits of the household need to change.  The planter is a living, breathing creature and it takes time and patience to figure out how to take care of it.

It takes at least 5 years to finish a house when you are doing it yourself.
At least.  We're still not done.


Image courtesy of Alan Howell, Star Path Images.