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Earth Sheltered Design


Sponsored in part by:

The Natural Builder
The Natural Builder
P.O. Box 855
Montrose, CO 81402
Phone/Fax: 970-249-8821

The Natural Builder offers on-site construction help, consulting and workshops related to natural plasters, earthen floors, monolithic adobe (cob), straw-bale and other green building projects.  We also authored The Natural Builder book series on Earthen Construction, Monolithic Adobe, and Earth and Mineral Plasters.  These books are available at our web site:  www.naturalbuilder.com.




Earth Sheltered Design Contents:

DEFINITION
CONSIDERATIONS
COMMERCIAL STATUS
IMPLEMENTATION ISSUES
GUIDELINES

RESOURCES


DEFINITION:

Earth-sheltered design employs the earth as a major component of a building's thermal control system.


CONSIDERATIONS:

Using the earth as a component of the energy system, or "earth-tempering," can be accomplished through three primary methods: direct, indirect, and isolated. In the direct system, the building envelope is in contact with the earth, and conduction through the building elements (primarily walls and floor) regulates the interior temperature. In the indirect system, the building interior is conditioned by air brought through the earth, such as in earth tubes. The isolated system uses earth temperatures to increase the efficiency of a heat pump by moderating temperatures at the condensing coil. A geothermal heat pump is an example of an isolated system. This discussion will focus on direct and indirect systems.

High humidity levels in our area may create mood problems in direct and indirect earth sheltered systems. Good ventilation and dehumidification can reduce these problems in direct systems. High temperatures and low ground moisture in the summer (moist soil conditions are preferable for best conductivity) must also be addressed for optimal benefits from earth sheltering.

In the winter, passive solar features can maintain comfort levels by warming the thermal mass. (Earth-sheltered homes are typically built with concrete, which has high-thermal mass.)

Costs for a home incorporating direct earth-sheltering can run about 10% higher than conventional building. Some manufactured systems are closer to conventional home costs. Lower maintenance and operating costs are typical for earth-sheltered homes.

Commercial
Status
Implementation
Issues
technology suppliers cost financing public regulatory
Earth Sheltered Design

Legend
green Satisfactory
yellow Satisfactory in most conditions
red Satisfactory in Limited Conditions
black Unsatisfactory or Difficult

COMMERCIAL STATUS

TECHNOLOGY:

Moderately developed. It is generally acknowledged that additional research is needed as well as standardization of terminology and measurements used by researchers. However, earth-sheltered homes and buildings have been successfully constructed throughout the world.

SUPPLIERS:

Limited.

COST:

Costs for an earth sheltered home can run 10% higher than conventional homes. Costs are location-specific.


IMPLEMENTATION ISSUES

FINANCING:

May require additional work with lenders. Numerous precedents exist.

PUBLIC ACCEPTANCE:

There is limited interest in this type of building due to lack of exposure to examples in our area and misconceptions regarding the interior environment of this type of home. The non-traditional appearance hurts general appeal.

REGULATORY:

The layout of the rooms will have to accommodate a means of egress from sleeping areas.


GUIDELINES

  • 1.0 Indirect Systems (Earth Tubes)