Green Technology Uses Earth to Maximize Comfort

An image of an earth sheltered home built into a country hillside.
Personalized Comfort
Earth sheltered homes take advantage of the soil’s natural tendency to change temperature much slower than the surrounding air.

Homeowners can employ innovative green technology and reduce energy costs by sheltering their houses in the earth.

Earth sheltered homes take advantage of the soil’s natural tendency to change temperature much slower than the surrounding air.

Reduce Heat Loss

By sheltering all or part of their homes in the earth, owners can reduce heat loss and keep temperatures steady throughout the seasons.

In addition, the earth offers protection from direct solar radiation and reduces air leaks in or out of the home.

The technology is ancient, although it’s been updated to take advantage of today’s advanced materials. Earth sheltered homes were used by the earliest humans, particularly in Asia and northern Africa.

Location is Important

When building an earth sheltered home, the right location is important.

Planners should choose sites where water drains away from the building. The house should sit above the water table – the upper limit of groundwater. It’s possible to build below the water table, but this can pose problems.

Granular Earth Ideal

The best earth with which to surround the home is granular, like sand or gravel. They compact well and can bear the weight of construction materials. They are also very permeable, draining quickly.

Builders need to make sure house walls are strong and waterproof to withstand moisture and bear the dead weight of the soil overlay. Reinforced concrete is the most common choice, because of its durability and fire resistance.

Bermed and Underground Homes

Earth sheltered homes come in two main types: bermed and underground.

Bermed homes are built above or partially below ground. They are suited to flat or slightly sloping terrain. Builders pile soil up against exterior walls and, sometimes, the roof. The soil slopes away from the house, much of which stays above ground.

Underground earth shelters are ideal for people who want their homes to blend in with the landscape. These houses are typically built on flat terrain and are completely below ground. Major living spaces, like living rooms and dining rooms, often surround a sunken courtyard or atrium, which lets in natural light and gives an open feeling.

Face Windows South

In cold climates, designers should make most windows face south to absorb maximum solar radiation. Typically the other sides of the house are earth covered.

Earth sheltered homes can thrive in both hot and cold climates and are more cost effective in areas of temperature extremes and low humidity.

Colorado Home

In the Rocky Mountain foothills of Evergreen, Colorado, with its cold winters, writer and green building expert Dan Chiras built an earth-bermed home that features numerous green technology innovations. The north part of the house is underground, while south facing windows capture the sun’s rays. The house keeps warm in winter and cool in summer with very little additional energy.

Massive Florida Heat Sink

In hot and humid Tallahassee, Florida, Mad Dog Design and Construction Company built an earth sheltered home that reduces the effects of high temperatures. The soil acts as a massive heat sink. The entire floor of the house and two-thirds of its wall area are underground.

Earth sheltered homes require less outside maintenance than other homes. They do, however, require care to avoid moisture.

Adequate Ventilation

Designers should plan for adequate ventilation. One good choice is installing an energy recovery ventilator, which exchanges heat in the outgoing exhaust air with incoming fresh air. The ventilator minimizes heat losses and keeps indoor air healthy.

Homeowners can join the green revolution while enjoying optimal comfort by using the earth’s moderating cooling and heating properties in designing their homes.

Ductless or limited-length ducted cooling and heating systems can be used to condition these unique homes, and the high efficiency of those systems won’t compromise the natural benefits of the earth sheltered home.


U.S. Department of Energy: Efficient Earth-sheltered Homes

Earth Shelters; A Review of Energy Conservation Properties in Earth Sheltered Housing, by Akubue Jideofor Anselm

Mother Earth News: Earth Sheltered Homes: Comfortable, Affordable and Energy Efficient

Mother Earth News: A Florida House With Natural Cooling

This article and its content are sponsored by Mitsubishi Electric US Inc., Cooling & Heating Division.

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