What is a Net Zero Building?
Today, most homes and commercial buildings are supplied with power, water, and other utilities through a network of pipes or wires that lead back to a central supply like a power plant. However, as renewable energy generation and energy efficiency technologies evolve, the possibility to live and work in a building that literally makes as much power as it uses has become more and more of a reality. Achieving this goal is often referred to as “net zero.”
Net zero is a simple, admirable, and appealing goal. And it’s important, because buildings consume more energy than any other sector of the economy. But what does it really mean?
That’s where the U.S. Department of Energy (developers of the ENERGY STAR® program) comes in, having recently released a definition of net zero as “an energy-efficient building where, on a source energy basis, the actual annual delivered energy is less than or equal to the onsite renewable exported energy.”
This clarifies some things, including the amount of energy computed annually (that means the occupants can use more than the building makes on some days as long as they use less on others, which tends to favor buildings that are not continuously occupied).
A further distinction is that net zero is not the same as off the grid. Off the grid means no external supply at all — complete self sufficiency on a day-to-day basis — while net zero means you may use electricity supply, water, or heating-fuel supply, but the total usage over a given time period is offset by the total amount generated by the building.
Whatever your definition, net zero energy is a laudable goal. Buildings that can make their own power, heat, and water are more resilient and can contribute to, rather than draw from, outside energy sources.
Balancing the needs over the course of the year is always the challenge — sometimes the building will take from the grid and sometimes it will give back, but the grid needs to be there for today’s net zero buildings to work. Battery technology and onsite water storage may ultimately change this, and energy efficiency — using less power, water, and heating fuels — is really the key.
The exterior building envelope, combined with reducing the needs of occupants to draw electricity, heat, and water, is really the key to reaching net zero, however you define it.
And products from GAF, such as EnergyGuard™ insulation, Timberline® Cool Series® Energy-Saving Roofing Shingles, and EverGuard Extreme® TPO, which create more energy-efficient spaces and are well suited for rainwater catchment and hosting solar arrays, make net zero more and more of a reality every day.