Straight Talk Articles
Can You Have a Zero Net Energy Home?
Dear Pat: I am considering installing some rooftop solar in my home, and a neighbor asked if I was going to have a “Zero Net Energy” home. Can you explain more about what that is? – Sally B.
Dear Sally: A Zero Net Energy (ZNE), or Net-Zero, Home is one where all the energy that is used in the home is completely offset by the production of on-site power, such as through rooftop solar photovoltaic panels. Having a ZNE Home does not mean that you are “off-grid” – instead, your home uses electricity from your co-op for daily needs—especially when the sun isn’t shining—but also supplies power back to the electric grid from your solar panels.
Other than solar panels, a Zero Net Energy Home may not look different from other homes.
Usually, the term ZNE Home describes a newly built house, as it is easier to custom-build a very energy efficient house and properly size solar panels that will match the expected energy use. However, existing homes can also be retrofitted to be ZNE! But before you go out and buy a solar panel system that will cover every inch of your roof, remember this mantra: “Reduce before you produce.”
Heat pumps or increased insulation may not seem as exciting as solar panels, but they can produce a better return on your investment, and they will increase comfort and improve the value of your home. Before you purchase and install solar panels, make all the cost-effective energy efficiency improvements you can—you will likely be able to reduce the number of solar panels you need, while also seeing sustained energy savings over time!
An energy audit is the first step to learning how to make your home as efficient as possible. An energy auditor will walk-through your home and perform tests to find out where air is leaking. An energy auditor can also perform energy modeling to tell you how much energy you would save by implementing certain improvements. If you are interested in an energy audit, talk with your co-op—they may offer an audit or have names of local energy auditors.
Retrofitting a home to be ZNE will likely require investments big and small. Upgrading your HVAC system to something very efficient is a large investment, but, as heating and cooling usually makes up half of the average home’s energy use, will have a substantial impact on your home, especially when combined with insulation improvements. Sealing up air leaks and changing out lightbulbs for LEDs are smaller investments, but can also help you reach ZNE. Behavioral changes, such as turning down the heat when you leave for the day, using your solar clothes dryer (a clothes line!), and turning off electronics and lights when you leave a room, are also small and easy ways to reduce your energy use.
Once you have reduced your energy use as much as you can, you can now think about producing. Solar photovoltaic panels are the most common residential renewable energy installation, though a small wind energy system could be a good choice if your home is on one of the rare sites that is windy enough.
There are also other ways to harness the power of the sun. For example, solar water heaters can be a cost-effective. Or you can use passive solar techniques, like strategic window placement, landscaping and shading, and specific building materials to heat certain areas of your home in the winter or reduce sun and heat exposure in the summer.
You may be able to also reduce your energy impact without purchasing your own rooftop solar panels. Many cooperatives are beginning to offer “community solar” or “solar gardens”, where co-op members invest in part of a larger solar installation that supplies the co-op’s electric grid. Participating in a community solar system gives you the benefit of solar power without needing to install and maintain your own solar panels. Talk with your co-op to see if they have community solar or are planning on it in the future.
This column is from the June issue of Straight Talk, which is a service of the National Rural Electric Cooperative Association to its member co-ops. Straight Talk is distributed by electric co-ops around the country as part of a monthly print publication or on co-op websites.
For more information about Zero Net Energy Homes, see this page for more resources.