After receiving certification, there are no other required checks or audits, which theoretically means buildings could operate at net-zero levels and receive certification before dropping off in efficiency. However, if you prepare well enough and incorporate appropriate systems and materials in your building, you are likely to maintain and even improve performance over time. Strong preparation and following through with the best energy efficiency practices are key to ensuring optimal performance, and getting occupants involved with these practices helps significantly.
“Having some kind of metering that is public and helps keep people aware of how performance is going is vital,” says Liljequist.
The idea of zero energy buildings might conjure images of the most advanced technologies and building systems or, for FMs, high costs. A lot of the systems and improvements that are necessary to make your facility net zero are expensive, but they offer high ROI when the right changes are made.
However, the costs associated with zero energy buildings are decreasing over time. One of the main reasons going zero energy costs less than it has in the past is because high quality, efficient building materials and systems are easier to find, more abundant in the marketplace and ultimately less expensive.
“There’s no cutting edge technology in our building. We just corralled the already existing energy-saving technologies in one place,” says Craig Neyman, vice president and CFO of the David and Lucile Packard Foundation, about the organization’s headquarters located in Los Altos, CA.
The Packard Foundation’s headquarters has consistently performed as a net zero facility, and it has paid off. Neyman notes that while the decision to go net zero was in large part motivated by the Foundation’s mission of conservation, the investment was defensible because of the building’s strong ROI.
If you are thinking about zero energy for your organization, you will want to consider your location. Some regions are more conducive to net zero energy based on climate – for example, sunny and more temperate areas will perform better with solar and place less of a demand on HVAC systems. Nevertheless, zero energy buildings can be put into use in any number of climates; it might just require more effort in buildings that weather harsher conditions.
Just as some organizations have found the cost of making a facility net zero energy, they have found that maintenance is typically simpler and a rarer occurrence than before.
“They tend to be more durable, simpler and easier to maintain,” explains Liljequist. “Often, the envelopes of the buildings are built better, so in the long haul you’re going to have less maintenance and less potential for rot if it’s a wood frame structure. Windows are often higher quality, so they’ll be durable. A lot of living buildings are using ground source heat pumps and heat recovery ventilators, and all that equipment is inside the building instead of being on the roof where it would be exposed to weather and is tougher to maintain.”
Steve Stenton, director of sustainability at RMW architecture & interiors, likens the durability and reduced need for maintenance in zero energy buildings to that of electric vs. gas cars, where electric cars have fewer moving parts and are therefore easier to maintain than a gas-fueled car. Likewise, because mechanical systems in zero energy buildings are typically smaller than that of a comparable conventional building, this generally equates to simplified maintenance.
“It’s based on the old adage ‘less is more.’ There are fewer things to go wrong with it and therefore generally fewer maintenance issues,” says Stenton.
Justin Feit firstname.lastname@example.org is a former Associate Editor of BUILDINGS. This article was originally published in 2017 and updated in 2018.
Systems That Contribute Most to Zero Energy Buildings
As zero energy buildings become more common, consensus is building about the most effective systems to contribute the best performance. Brad Liljequist, zero energy director at the International Living Future Institute, highlights the following four systems as having the greatest impact:
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Envelope: Liljequist starts with the building envelope, which can in many cases be the easiest to retrofit in a building. The key is making sure your building is properly air sealed, and most facilities that have successfully met zero energy goals have paid attention to the air barrier and are doing performance testing. Common envelope improvements include double and continuous insulation and high performance windows.
Heat Pump: Because of the amount of innovation that has happened in the last 10 years, the right heat pump can be a great technology to make your building more energy-efficient.
Plug Loads: “People are really paying attention to occupant loads using individual submetering to understand how individuals are using power in the building,” says Liljequist. The switch to LEDs and more widespread adoption of daylighting also contributes positively.
Solar PV: On the energy generation side, solar PV is typically the best way to produce power in your facility. In some cases, on-site wind energy can be a means to fulfill your facility’s generation needs.