Sustainable energy in housing

StoryImage( ‘/Images/Story//Auto-img-115817446412103.jpg’, ‘Photo by Vic Zaderej’, ‘Hollow cores to be filled with concrete and used in the foundation construction of the “One-Watt House.”’);

Dr. Bernd Steinmuller, a German physicist active in energy efficiency, made a keynote presentation at this year’s Renewable Energy and Sustainable Lifestyle Fair. He declared that sustainability should be the guiding concept of development during this century. We have already exceeded the natural limits of the planet in many ways. Problems will continue to intensify as a result of expanding human populations and increasing economic inequalities. Energy is our most important sustainability issue as supplies are dwindling and reserves are located in politically unstable areas of the world. A simple example of sustainability is not cutting down more trees than can grow to replace them.

In addition to dwindling supplies, Steinmuller reminded us that we have exceeded the ability of the atmosphere to absorb carbon by a factor of 2 leading to global warming. The 20 billion tons of carbon already released to the atmosphere by human activity must be reduced to 10 billion tons by 2050 to stabilize the climate. The western world must reduce its high levels of carbon releases by a factor of 10.

Dr. Steinmuller presented many opportunities for reducing carbon through cutting energy consumption. Resulting benefits include cost reductions, ecological improvements, health benefits and reductions in international tensions arising from energy demand. When efficiency improvements are combined with renewable energy, a 10-fold decrease in carbon dioxide releases by 2050 is possible.

In 2005, renewables supplied 6 percent of Europe’s electricity, which has helped reduce CO2 releases to the atmosphere. By 2010, renewables are targeted to supply 12 percent of Europe’s electrical needs. For 2020, the goal is 21 percent. Expanded use of renewables alone could achieve half of Europe’s needed reductions in CO2 by 2050.

Steinmuller estimates energy used by housing in Germany and the United States, which accounts for 40 percent of their energy use, could be cut by a factor of ten. The strategy relies on decreasing heat lost through the envelope of the building—its foundation, walls and ceilings as well as doors and windows. Heavy investment in insulation saves money on heating equipment and fuel bills.

In the 1970s, Phillips company designed a model home to save energy, assessed its performance and produced formulas to make estimates on how model homes would perform in five climate areas of the world. The heating load was cut by a factor of 5 compared to traditional homes. The model home in Germany used 30 kilowatts or less for heating, while the average German house uses the equivalent of 150 kilowatts per square meter.

Strategies used included adding 10 inches of insulation to the walls and ceilings, using the most energy-efficient windows available, recovering 90 percent of the heat released from the house through proper ventilation and heating the home with a heat pump linked to an earth tube looped around the foundation.

Subsequent studies and work developed what is known as the Passive House. A home being built southeast of Oregon, Ill., known as the “One-Watt House,” follows passive house principles. It is designed to require one watt of electricity per square foot to heat. This means that a similar 2,000-square-foot house could be heated by the equivalent of 20 100-watt light bulbs on the coldest night in winter.

The principles of a one-watt house can be applied to both new construction and renovated buildings. A good time to incorporate passive house principles into an existing house is when it is in need of renovation. We have known how to build these energy-efficient buildings for more than 30 years but have failed to do it on an appropriate scale to avoid climate change. Cheap energy prices produced unsustainable energy consumption patterns.

There are now 10,000 new and renovated buildings following the principles of the Passive House around the world. Most are in Europe.

Government policies providing sufficient incentives for renewables and energy efficiency have made Germany a world leader. The U.S. could do the same.

This column is based on a presentation by Dr. Bernd Steinmuller, Aug. 12, 2006, at the Ogle County Fairgrounds.

From the Sept. 13-19, 2006, issue

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