Benefits Only Some Net Zero Energy Homes Enjoy
A net zero energy home can start as any home. They usually fall into three categories:
- Older existing home
- Conventionally built new home
- A home built to or renovated to a green home building standard
Any of these homes with a PV solar panel system large enough to offset ALL the energy the home pulls from the power grid, and that has a net meter, can be called a Zero Energy Home.
However, starting with a green home such as a Zero Energy Ready Home, Passive House, LEED, or National Green Building Standard Home, a Net Zero Energy Home will enjoy additional advantages such as:
- The size of the PV solar panel system can be much smaller, and they cost much less
- While older homes and new conventional homes may qualify as net zero energy, they will not be as comfortable as starting with a green home. Green homes are built to be virtually air-tight and are super-insulated; this means no drafts from outside and a more even temperature and humidity throughout the home.
- Older and conventionally built new homes do not normally have the fresh air ventilation systems, radon prevention and mitigation systems built-in, nor high-performance air filtration systems assuring high indoor air quality and a healthy environment as green built homes do.
- Non-green homes may have building materials that give off unhealthy gases known as VOCs.
- Non-green homes don’t have these and other benefits only green homes offer.
Grid-Connected and Non-Grid-Connected Zero Energy Homes
In most areas, a zero energy home will be connected to the electric grid. This is so it can pull power when the home’s solar panels don’t produce enough energy for the home. For a grid-connected home with solar panels to be net-zero energy, the home must be connected to the power grid in such a way that the clean energy produced by the solar panels (in excess of what the home is using at the moment) can be fed back into the grid to offset the energy the home pulls from the grid, such as at night.
The type of connection used to allow this to happen is called a net meter or bi-directional meter. It allows energy to flow to and from the home and grid. A net meter measures the flow in each direction to determine if the home is producing more, less, or the same amount of energy it uses from the grid.
A net zero energy home is one that feeds into the grid at various times the exact amount of energy it pulls from the grid at other times. If it comes close to equal, it is called a near-zero energy home. If it produces more energy than it uses, it is called a Positive Energy Home.
With the use of home-scale batteries, like those starting to be used more and more, a home can store energy from its solar panels when they are producing more energy than the home is currently using. The home then draws power from the batteries when the solar panels don’t produce enough energy for the home.
Home-scale batteries are not commonly used today because of price. PV solar panels with batteries are starting to come down in price and have increased storage performance. Within a few years it is likely even homeowners who have access to the power grid may find PV solar panel and battery systems a better solution for their homes than being grid-connected.
Right now, battery systems, backed up with diesel, gas, or propane power generators, can be used by homes where there is no electric power grid.
A Net Zero Energy Home is Possible Even if You Use Some Natural Gas
If you can’t live without a gas stove or gas fireplace, you can still have a Zero Energy Home. To do this, you need to generate enough excess electrical energy with your solar panels to offset the greenhouse gases caused by your use of natural gas.
Net metering practices vary from area to area. Offsetting your use of gas by installing additional solar panels may or may not provide the same financial benefit as offsetting your use of electrical energy from the power grid.
However, if Net Zero Energy is what you are seeking, it can be accomplished.