What is a Net-zero and Net-energy home?
A Net-zero home is a home built with an eye toward energy conservation; using advances in building methods and energy production/conservation, these homes produce as much energy as they use on an annual basis, so they aren’t a drain on natural resources.
This doesn’t necessarily mean that Net-zero homes are off-grid. They can be connected to the grid, drawing on it when they need power and returning excess energy to the grid when they are producing more than they can use. As long as the annual net-energy consumption is zero, a home can be called Net-zero.
Net-zero homes are equipped with photovoltaic systems that allow them to capture and utilize renewable solar energy so they need not rely on non-renewable sources of power. According to the Canadian Mortgage and Housing Corporation, they may also include technologies and practices that enhance indoor air quality and comfort, reduce environmental impact, conserve natural resources and improve affordability.
For those who aren’t yet ready to invest in solar panels, there are also net-ready homes that are designed to allow for solar panel installation at a later date without making major adjustments.
In 2017, the Canadian Home Building Association launched a Net-zero home labelling program to recognize Net-zero homes and promote their construction. Potential changes to building codes could soon require all new housing to meet a Net-zero standard by 2030, so stay tuned.
Features of Net-zero homes
Net-zero homes have three aims: to include renewable energy systems, to reduce energy requirements, and to operate efficiently.
Most Canadian Net-zero homes use photovoltaic systems that convert sunlight to electricity. They have the advantage of being low maintenance, safe and reliable while producing no emissions or pollution on site. They may also have rooftop solar panels that produce hot water.
The Net-zero home reduces energy needs in a variety of ways. It generally has outstanding insulation all around the building to prevent heat or cold from escaping, depending on the season. The home is generally oriented east-west on its lot so that many of the windows face south and take advantage of the sun’s light and heat to reduce energy costs.
Net-zero homes may include roof overhangs and take advantage of natural shade to prevent the homes from getting too hot. They often have energy-efficient mechanical ventilation that provides an ongoing exchange of stale indoor air for fresh, outdoor air to ensure that the indoor environment is as healthy as possible.
To recover energy that might be wasted during exhaust and wastewater disposal, Net-zero homes may incorporate heat recovery ventilation systems and wastewater heat recovery systems.
The appliances and lighting fixtures, as well as the heating and cooling systems, must be consistent with the energy-efficient design of the home.
For homeowners who are attempting to be as energy conscious as possible, it’s useful to have a display or dashboard that offers real-time data about the home’s energy consumption and production so that the residents can adjust their behaviors accordingly.
