A net-zero building is a building with zero net energy consumption. Over the course of a year, the total amount of energy used by the building is equal to the amount of renewable energy created by the building, often onsite. Net-zero homes and commercial buildings are seen as more environmentally-friendly compared to traditional buildings, appealing not only to occupants but also to state and local governments.
The Growth of Net-Zero Homes
Several trends are driving the growth of net-zero homes. Designers and builders are looking for an edge to promote their buildings. At the same time, new building codes are focused on improving energy efficiency. Sustainable building initiatives are not only the norm, but they’re a way to reduce operational costs. Most utility companies offer rebates and incentives to offset the initial costs.
California leads the way with new energy-efficient building codes and standards. The state aims to have all new residential construction attain net-zero status by 2020 and commercial construction by 2030. Developers and builders are working on buildings that use less energy and create renewable energy on-site. The approaches, designs, and materials used are becoming more efficient, making net-zero buildings affordable for many residents and businesses.
Most net-zero homes still connect to a power grid since renewable power technologies such as wind and solar do not always generate enough power at peak energy usage times. There must be provisions for energy storage either on the grid or onsite.
Energy or thermal storage technologies capture the renewable energy, rather than returning it to the grid. The sun doesn’t shine at night, and the wind is not always blowing, so at these times, the building needs to get energy from the grid or onsite storage. Control strategies are essential, and utility services such as load shifting and demand response help to make these investments worthwhile.
Minimize Energy Use
The other side of the net-zero equation involves reducing the amount of energy that the building uses. The less energy used, the less renewable energy required to offset that demand, and the lower the operating costs. New high-efficiency HVAC and lighting technologies play a significant role in meeting energy targets. HVAC systems designers develop strategies that address cooling, heating, and air circulation for occupant comfort.
Today’s high-efficiency equipment delivers capacity modulation to precisely match the needed heating and cooling. Modulating air conditioning systems provide lower energy consumption, improved humidity control, better air quality and a more comfortable environment throughout the whole home or building.
Collaboration is Key
Net-zero homes require cooperation between the building designer, construction team, owner/operator, and often, the occupants. The building envelope and lighting are vital considerations. All devices, even those that plug into the wall, must be energy efficient. Peak loads must be carefully planned for, especially when selecting heating and cooling equipment during extreme outdoor temperature conditions. HVAC equipment designers work with the most efficient compressors, fans, and pumps, coupled with advanced controls, to meet the net-zero energy goal. The result is a more efficient system that uses less energy and saves operational costs.