California has set a target for all new homes built after 2020 to be net zero energy homes or net zero energy ready. What do they mean when they talk about net zero energy, and how will that impact us in Oregon?
A net zero energy home is one that generates about the same amount of energy on site as it uses, usually through energy efficient construction and solar electrical generation. Most net zero houses are connected to the electrical grid and at times use power from the grid and other times put power back into the grid. Energy can also be generated with on-site wind, geothermal or hydroelectric generation.
The reason for building net zero energy houses include a desire to reduce reliance on fossil fuels, reduce carbon emissions, improve disaster resiliency and improve comfort. A net zero house insulates the owner against future cost increases for fuel and lower monthly utility costs.
A net zero home will usually have extremely well insulated walls, floors and ceilings. They may reduce the size and number of windows, and the ones that remain are extra efficient. Design and orientation on the lot will take into consideration the potential to harvest passive solar heating in the winter and reduce it in the summer and to take advantage of sheltering from the wind. Skylights or solar tubes can reduce lighting needs during the day time. Careful attention will be given to reducing air leakage
Highly efficient appliances will be used that not only use less energy. Heat recovery systems for waste water and waste heat from appliances may be installed to use for supplement water heating.
Energy is most often generated from solar electrical panels on the roof. When the panels generate more electricity than is being used on site it is sent through the meter to the utility company. The solar panels will be sized to average enough generating capacity to equal energy usage throughout the day.
Technology to build a net zero house is readily available. But thicker walls, tighter construction and efficient design require different construction methods and skills. Special attention to detail is necessary to avoid moisture problems. A builder and their subs will need to clearly understand this is not an ordinary house and expect to take a little longer to complete the work when building their first net zero house.
What about net zero energy homes in Oregon? What California does is likely to trickle into Oregon. California’s emphasis on reducing energy use and carbon release is likely to embolden energy conservation activists in Oregon. Well-funded groups are likely to push for new rules or regulations to require greater efficiency. It may not be a matter of if net zero gets to Oregon, but when.