There are two ways to define a net-zero energy building. One definition comes from the head. The other comes from the gut.

In a technical sense, a net zero energy building is one in which the building produces as much energy as it consumes. In such a building, its energy load is reduced to a minimum. Then, onsite renewable sources generate enough energy to not only supply the building's remaining energy needs, but also to return the energy consumed to the electric grid.

That's the technical side. Here's the gut side: Net-zero energy buildings are the acid test of the quality of the HVAC contractor's work.

“Usually when we're talking about a net zero energy building, we're talking about one that consumes about 50% of the normal energy of a building today, and the remainder is made up from onsite renewable means,” says Kent Peterson, P.E., vice president and chief engineer, P2S Engineering Inc., Long Beach, CA.

“It's important to note that energy-efficiency is the first step. These buildings are still consuming some amount of fossil fuels. So it's not just a matter of adding a bunch of solar photovoltaics to a building and saying it's net-zero,” says Peterson, who is also a Leadership in Energy and Environmental Design (LEED®)-Accredited Professional (AP)and the 2007-2008 president of the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). “The concept is to create a highly efficient facility that balances out its annual energy consumption needs with the creation of energy onsite, from renewable sources.”

That concept is sound, but what a net-zero energy building means from a contractor's perspective is simple, says Dan Thayer, P.E., president, Thayer Corporation, Auburn, ME.

“If you design a net-zero building, it's going to be apparent very quickly if the building is working properly or not,” Thayer says. “If the mechanical systems weren't properly designed, installed, commissioned, and maintained, they're going to consume an inordinate amount of energy and that building is going to show up as net-negative. So these buildings present an acid test for the HVAC contractor.”

Matt Mullen, P.E., an engineering consultant for EMCOR Services - New England Mechanical, Vernon, CT, is also a LEED AP. He says contractors would do well to familiarize themselves with net-zero the way they did with LEED.

“If you look at the way LEED has come on over the last 10 years, I think it's only natural to see the same thing with net-zero,” Mullen says. “The pace will be slow at first, but I think we'll see institutions such as colleges, universities, and government agencies increasingly adopting net-zero requirements for their projects. Eventually, net-zero principles will begin to be adopted into code, just like we're seeing now with LEED. There's a momentum that's building in the country right now.”

Peterson notes that California has adopted an energy plan that calls for all residential developments to be net-zero by 2020, and all commercial developments by 2030. The technologies that can be used to achieve net-zero — such as solar photovoltaics, wind power, cogeneration, microturbines, and geothermal heat pumps — are readily available, and many are becoming less expensive as they become more widely adopted.

Integrated Design a Must

Net-zero buildings present both opportunities and challenges for HVAC contractors.

“There's a definite opportunity here for contractors who are knowledgeable about net-zero buildings. Interest in it is only going to grow, and if you can establish yourself as the expert early on, you can really differentiate yourself in your marketplace,” Mullen says.

However, along with that opportunity comes increasing complexity of systems and more reliance on other entities to ensure that a building performs as advertised. This means contractors must take to heart the ideas of whole building design and construction and integrated building design.

“Creating these buildings will really take a collaborative process. There are many aspects to creating a high-performance, low-energy building,” Peterson says. “This includes building envelope measures, the mechanical systems that are being selected, the lighting systems and renewable energy systems, and how they all integrate. Optimal integration of the energy-savings strategies and renewable energy systems are needed to accomplish a net-zero goal.”

Thayer agrees. “The first challenge, if you're the Design/Build mechanical contractor, is to determine if you have adequate control of all the elements that you'll need control of,” he says. “Someone has to be looking at the overall picture and pulling together a comprehensive strategy. You can't work in a vacuum.”

Expertise in building management and control systems will be more important than ever in the era of net-zero buildings, Thayer says. The control system will be the heart of what are sure to be increasingly complex systems that must interact. But he adds that no matter how intricate your system or how brilliant your controls, you can't overlook the fundamentals of good system design, good installation, and good commissioning.

It's this last element that may trip up many contractors who are attempting to create net-zero buildings.

“Contractors offering a net-zero product had better make sure that their commissioning program is everything that it needs to be,” Thayer says. “Frankly, I think most mechanical contractors would say that on a scale of 1 to 10, their commissioning isn't consistently a 10. But if you're in a net-zero building, you'd better be pretty darn high on the scale.”

Increased Value of System Maintenance

Mullen adds that there's a risk in any type of performance-oriented contract. If a project doesn't meet specifications, the owner will look for someone to blame — and in a net-zero energy building that “someone” is likely to be the Design/Build HVAC contractor. However, the reward for taking on this type of risk is a customer who is very aware of the value of system maintenance. That's sure to be music to your service department's ears.

“While in the past some building owners may have been lackadaisical about maintenance, they're certainly going to be more enlightened now,” Mullen says. “They'll certainly understand how imperative it is that the equipment in a net-zero building must be kept operating as it was designed, if the building is going to maintain that high level of performance.

“You're not just going to be able to put together a building this complex and then walk away from it. You're going to have to keep looking at it and assessing it to make sure it keeps performing at net-zero as it was designed. Design/Build HVAC contractors are perfectly positioned to conduct that type of ‘continuous commissioning.’”

And amidst all the technology, opportunities, and challenges, don't overlook one key benefit that net-zero energy buildings provide for high-quality HVAC firms: the ability to shine where others don't.

“It's a pretty sad commentary on the way we perform our trade that 80% of the buildings in this country never operate the way they're intended,” Thayer says. “I think it's about time we started putting some hard criteria in front of our customers. When you start to certify buildings as net-zero, the results — and your performance — are going to show up pretty doggone fast. And maybe it makes the industry as a whole step up and do a better job.”

For more on net-zero concepts, visit Contractingbusiness.com, keywords “net-zero.”

Also: The American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) hosts a conference on net-zero energy buildings in March in San Francisco, CA. ASHRAE's Countdown to a Sustainable Energy Future: Net-Zero and Beyond takes place March 29-31. Call 415/563-1234 or visit ashrae.org/netzeroconference.