If only net zero energy buildings were like cheap baseball caps.  One size would fit all.  Unfortunately, reality is very much case by case and often times there are circumstances that prevent a correct fit from being achievable.  These limitations come most often in the vehicle of a financial excuse, but can also be the result of serious design constraints such as weather patterns and roof space.  Also, keep in mind that most clients will not understand net zero design so it will be an uphill battle to convince them to increase a project’s complexity and timeline.

Like cooking a first-class meal, net zero buildings require the right ingredients at the right time with the budget and skill to match.  As my Building Performance Institute (BPI) instructors love to say, “there is no silver bullet, just a thousand silver BBs”.  To achieve a net zero building, one must find reliable information about the thousands of ingredients.

In my academic perspective, net zero design revolves around three core aspects.  These are: best practices in energy efficiency, on-site clean renewable generation, and smart building systems.  In addition, on the human energy side of the equation, it is absolutely crucial to use an “integrated design” approach.

We can no longer function in a society ruled by silos.  As a recently initiated green building professional, it is an absolute mystery to me why the traditional approach to projects separated architects, engineers, and builders.  This seems like a great way to waste money achieving a less than optimal design as each contributor operates under their own incentive structure and has to limit risk for their own operations.  How did it take until the 21^st century for this industry to realize that putting the WHOLE team in the same room with one goal is a good idea?

In order to hit the lofty goal of net zero design, buildings can no longer be viewed as a sum of their parts.  Instead, they must be viewed scientifically as a system where one component has multiple functions and influences.  To use a classic example, skylights decrease lighting loads during the day; however, they also tend to create leakages in the building envelope resulting in decreased thermal performance.  Another common misstep is that in order to pass on liability, each subsequent building professional will increase the size of the HVAC equipment.  Not only will this increase ongoing costs and environmental impacts, but it will also eat up scarce capital budgets.  Instead, if the money goes towards best-practice building envelope (i.e. air-sealing, low-e windows, properly installed insulation, etc.) and more efficient lighting, you have a comparable upfront cost with lower material impacts and serious operational savings.

In addition, green building rating systems, such as LEED, are not going to be a good guide towards reaching net zero energy.  This is because these rating systems are prescriptive in nature and you maximize the possible points far before reaching net zero energy.  I believe it is valuable to think of energy systems as a microcosm within buildings.  In other words, you should decide to create a LEED Platinum building, design the energy system, and then design the rest of the green building.

Another important point is that on-site generation cannot be an afterthought.  Everything about the building must cater to the ultimate goal of net zero energy.  This means utilizing passive solar design and maximizing the rooftop to volume ratio which minimizes the complexity of the building systems.  I would go so far as to say purchase (or budget) the photovoltaics, solar hot water, microturbines, or geothermal systems before anything else.  These are enduring fixed assets that can be depreciated financially and appreciated visually.

Lastly, without a smart building system there is no way to reliably sustain net zero energy performance.  If financially possible, net zero buildings should provide for data collection, analytics, and control at a DEVICE level.  In other words, every light, furnace, boiler, compressor, evaporator, fan, and plug-load should have an independent and interoperable smart building unit.  Going one level deeper, the individual aspects of the building need to be understood as an integrated system in the context of ambient environmental conditions and usage patterns.  This may sound impossible; however, many established companies from the IT boom are now utilizing familiar technology to convert our energy system into something as sophisticated as our communication network.

Net-zero design is simple conceptually, yet extremely complex to implement.  The ten commandments of net zero buildings seem to be:

1. Utilize integrated design
2. Make net zero energy the goal from the first day
3. Target less complex buildings (recreation centers, distribution centers, retail, etc.) that have sufficient roof space
4. Work directly with the building owners and tenants
5. Partner with the local utility for incentives and analytical assistance
6. Get an experienced team that is able to step outside their comfort zone to explore options
7. Only use products that have been field tested and proven to perform
8. Keep it as simple as possible
9. Understand that models are not reality (thus ongoing commissioning is crucial)
10. Engage the community to keep your momentum going when things get rough
    
    

Note from the Editorial Staff: Lucas is a member of the Net Zero Buildings group here within the Green Building Pro community. We encourage you to join in on the discussion with your thoughts and experience regarding net zero construction. Click here to check out the group.