A solar-electric-system generates electric energy for the house and over the year the kilowatt-hours of electric energy exported to the grid equals the kilowatt-hours of electric energy imported from the grid. A NZE house is always connected to the electric grid. In the winter more electricity is imported than exported and in the summer more is exported than imported -- the net result over the year should be roughly zero kilowatt hours.

Since the roof size available is limited a NZE house must naturally reduce its energy consumption dramatically so that the size of the solar-electric system is practical. This always starts with exceptional insulation (in the range of R40 or higher), triple-glazed windows, and significant attention to all aspects of the building envelope.

A NZE house often has a method of collecting heat in the winter. Heat gain methods can include large windows for passive solar space heating, solar thermal collectors for domestic hot water, or other solar thermal air-heating technologies. A NZE house always starts as an ultra-efficient house so that the size of the solar-electric system can be fit onto the available roof space.

NZE houses still pay for electricity utilities. Electric service and the delivery of electric energy will still be present even though the net kilowatt-hours over the year are zero. A NZE house will be an all-electric home with an electric source of heat. Some NZE houses choose to include a wood stove for comfort and additional energy security however a wood stove is "input energy" that is not included in the NZE calculations. A house that uses external energy from wood, natural gas, or propane is only a NZE house if the solar-electric system exports to the electric grid an amount of energy equal to this external energy source.

In the new Energuide rating system an NZE house would have a rating of 0 GJ/year.

We may list a home as SC if an Energuide rating is not available or if we can't determine if the house will fit into any of our other categories.