A net Zero home, at a minimum, supplies to the power grid that is equal to the amount of power purchased from the grid. In many cases, the entire energy consumption (heating, cooling and electrical) of a net-zero energy home can be provided by renewable energy sources. A net-zero energy home will always cost less to operate. Over many years, this savings will add up, providing below market costs for heating, electricity and cooling. The second benefit is lowered carbon footprint for developments. The third and most critical benefit is the health of the occupants of a net zero home, since fuels are not burned, emissions are non existent, lighting is abundant, the environment of a netzero home is much healthier to live in. This rewarding trend is spreading across the country.

The development of Net Zero Housing or ZEB (Zero Energy Buildings) have been made possible through the progress made in new construction technologies and techniques, and advances in energy capture devices like low e glass, higher efficiency Photo Voltaic Panels, and so on. ZEB are very popular in Canada, Europe and Australia, and are gaining popularity in the US, for good reason. It is a smart investment.

To achieve minimal energy use, the design and construction of zero energy buildings departs significantly from conventional building practice. In conventional building design, the emphasis is normally on minimizing construction costs. Designers rarely do any energy analysis or life cycle operating cost calculations beyond those necessary to comply with local building codes.

In the ZEB approach, every decision about major sub-system selection is evaluated in terms of its future consequences on energy demand using life cycle energy analysis. ZEB designers are usually prepared to increase construction costs if doing so will reduce energy demand and operating costs by an equal or greater amount. The ZEB approach might be described as "energy first" building design. There are grants and low interest loans for this kind of construction.

In addition to using renewable sources, zero energy buildings are also designed to make use of energy gained from other sources, natural lighting, and ground source heat pumps. They are normally optimized to use passive solar heat gain, large thermal mass to even out temperature variations throughout the day, and in most climates are super insulated. All the technologies needed to create zero energy buildings are available today.

Designers typically use sophisticated computer simulation tools to take into account a wide range of design variables such as building orientation (relative to the sun), window type and placement, roof overhang depth, insulation values of the building elements, air tightness, the efficiency of heating, lighting and other equipment, as well as local climate. These simulations help the designers to know how the building will perform before it is built, and enable them to model the financial implications on building cost.

Zero energy-building concepts can be seen as a progression from other low-energy building techniques. Amongst these, in the US is LEED and in Canadian R-2000 and the German passive house, standards have been influential. Government and internationally sponsored demonstration projects such as the first super insulated Saskatchewan House, and the International Energy Agency's Task 13 have also played their part. And, in particular, the many enthusiastic private individuals who commissioned houses using cutting-edge low energy technologies have been vital.

One of the first ZEB office buildings is the 69-story Pearl River Tower, which will open in 2009 as the headquarters for the Guangdong Tobacco Company. This building takes advantage of both high-energy efficiency and energy generation from both solar and wind, to create a ZEB design.  In the US, ZEB research is currently being supported by the US Department of Energy Building America Program, (http://www1.eere.energy.gov/buildings/building_america/).  This group includes five industry-based consortia and researchers at the National Renewable Energy Laboratory (NREL), the Florida Solar Energy Center (FSEC), Lawrence Berkeley National Laboratory (LBNL), and Oak Ridge National Laboratory (ORNL).  There are many other exciting Net Zero developments going on in the US, just Google Net Zero.

This document was produced by the Putney Energy Committee, to encourage green development in Southern Vermont.

NET ZERO Information from Wikipedia online  - used by Daniel Hoviss – PEC chair and Putney Town Energy Coordinator.