Zero-Energy Building vs. Eco-Friendly Construction

As the construction industry adapts to new trends in zero-energy construction, many often wonder if their initial design concepts automatically adhere to eco-friendly principles, as well.  Otherwise known as net zero building, this process focuses on the energy consumption of the structure over its lifespan.  Meanwhile, eco-friendly or green building practices concentrate on the potentially positive or negative effects of the structure on all aspects of the environment, not just energy consumption, over the long term. 

To add even more confusion to the terminology debate, some forward-thinking architects and engineers are delving into off-the-grid construction.  These types of structures are essentially stand-alone zero-energy buildings that never connect to the federal, state or local power grid.  They are completely self-sustaining, usually through renewable energy resources such as solar or wind power.

Zero-energy building practices and materials  

A zero energy building (ZEB) also relies on renewable energy resources, but not to the same extent as off-the-grid structures.  According to the U.S. Department of Energy, a ZEB is “an energy-efficient building where, on a source energy basis, the actual annual delivered energy is less than or equal to the on-site renewable exported energy.”   Therefore, by definition, a ZEB is connected to the public grid.

The “energy” of the building includes all power sources

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used for heating, cooling, air filtration systems, indoor and outdoor lighting, hot water, transportation within the structure, and any other sort of energy used to power any conceivable machine or fixture within the building envelop. 

This energy can be provided through the public grid or via on-site renewable resources.  The calculations for the total energy used on-site must also account for the energy consumed in the extraction, processing, and transportation of primary fossil fuels such as oil, natural gas, and coal.  Designers even take into consideration the energy losses resulting from thermal combustion processes in power plants.

Eco-friendly building practices and materials  

Just because a building is considered zero-energy does not necessarily mean that it is also eco-friendly.  The reverse is obviously true, as well.  Eco-friendly building practices involve three primary areas:

• The efficient use of water, energy, building materials, and environmentally preferred products.
• The reduction of waste, pollution, and degradation of the environment.
• The improved health and productivity of the structure’s inhabitants.

And much like zero-energy designers, eco-friendly architects and engineers are also concerned with renewable energies.  However, rather than their primary objective being a zero-or-less cumulative difference between renewables and grid-connected resources, eco-friendly designers are more concerned with the Big Picture.  Energy consumption is not the only consideration.

For example, an eco-friendly interior designer might choose a natural bamboo flooring over a synthetically produced wall-to-wall carpeting.  Or an eco-friendly architect might opt to use reclaimed lumber from the demolition phase of a previous project for use in the construction of a building addition or remodel.  They also worry about the chemical emissions and biological pollutants that their paints, solvents, and composite timbers might release into the atmosphere. 

There is a growing consensus among scientists around the world that the oil and gas industry may well reach its peak within the next twenty years.  Global demand is soaring while production is rapidly declining.  Both eco-friendly and zero-energy building practices involve a commitment to energy conservation and a reduced dependence on fossil fuels over the lifespan of the structure.  They simply address these critical issues with varying levels of urgency.