Heating, ventilation, and air conditioning (HVAC) systems are a critical component of any building’s infrastructure. They are responsible for maintaining indoor air quality and ensuring a comfortable environment for building occupants. However, HVAC systems can also be a significant source of energy consumption and cost for building owners and managers. Therefore, it is essential for FMs to improve the efficiency of their HVAC systems to reduce energy costs and improve the overall building performance. Here are some ways you can improve the efficiency of your building’s HVAC system.
Conduct Regular Maintenance
Regular maintenance is essential to keeping HVAC systems functioning at their best. Facilities managers should schedule regular inspections, cleanings, and repairs to ensure that HVAC systems are running efficiently. Neglected HVAC systems can lead to dirty filters, clogged coils, and leaky ducts, which can reduce performance and increase energy consumption. Regular maintenance can help prevent these issues, extend the lifespan of the system, and save energy and money in the long run.
Use High-Efficiency HVAC Equipment
Upgrading to high-efficiency HVAC equipment can significantly improve the efficiency of the system. Facilities managers should consider using equipment that meets or exceeds industry standards, such as those certified by ENERGY STAR. High-efficiency HVAC equipment uses less energy than traditional equipment, which can lead to significant energy savings over time. Moreover, high-efficiency equipment is often designed to operate at part-load conditions, which can result in additional energy savings during periods of low demand.
Install Programmable Thermostats
Programmable thermostats are a valuable tool for improving HVAC system efficiency. They allow facilities managers to set temperature schedules that align with the building’s occupancy schedule. For example, the thermostat can be set to lower the temperature during non-business hours or weekends when the building is unoccupied and raise it before employees arrive. This simple step can reduce energy consumption and lower energy costs significantly. Also, consider automating your after-hours HVAC program or going HVAC on-demand for the weekends. These programs cut energy waste while giving your tenants more flexible work hours.
Optimize Airflow
Optimizing airflow is another essential factor in improving HVAC system efficiency. Facilities managers should ensure that HVAC systems are designed to deliver the right amount of air to each area of the building. The air ducts should be sized correctly to match the load requirements of the building, and they should be sealed to prevent air leakage. Additionally, filters should be checked regularly and replaced as necessary to ensure that the system is not overworking to compensate for restricted airflow.
Consider Renewable Energy
Facilities managers should also consider integrating renewable energy sources into their HVAC systems. Renewable energy sources such as solar and geothermal can provide an energy efficient and sustainable source of energy for HVAC systems. Solar panels can generate electricity to power the HVAC system, while geothermal systems can use the ground’s stable temperature to heat or cool the building. Although these options may require significant upfront investment, they can provide long-term cost savings and reduce the building’s carbon footprint.
Improve Building Envelope
Improving the building envelope is another way that facilities managers can improve HVAC system efficiency. The building envelope includes the walls, roof, windows, and doors that separate the indoor and outdoor environments. Improving insulation, weather stripping, and window and door seals can reduce heat transfer and prevent air leaks, resulting in less heating and cooling energy needed. The HVAC system will have less load to handle and thus function more efficiently.
In conclusion, improving the efficiency of HVAC systems can significantly reduce energy consumption and lower costs for building owners and managers. Facilities managers can achieve this by conducting regular maintenance, using high-efficiency equipment, installing programmable thermostats, optimizing airflow, considering renewable energy, and improving the building envelope. With these steps in place, facilities managers can ensure that their HVAC systems are functioning optimally, providing comfortable environments for building occupants while saving energy and money in the long run.
Fault detection and diagnostics (FDD) is the process of identifying and analyzing malfunctions or failures within a building’s systems to detect and diagnose faults as early as possible. Early detection minimizes the impacts of downtimes, prevents future failures, and improves overall system performance. FDD is crucial for maintaining the reliability and efficiency of a building’s HVAC system.
How Do FDD Systems Work?
FDD is typically achieved using sensors, monitoring systems, and diagnostic algorithms. These tools work together to continuously monitor the performance of the system and detect any abnormal patterns that may indicate a fault. The diagnostic algorithms then analyze the collected to identify the specific fault and provide recommendations for how to address it.
One of the key benefits of FDD is that organizations can proactively identify and address potential issues before they lead to costly downtime or equipment damage. Too often, building owners, maintenance staff, and systems integrators work within a reactionary model, which often follows these steps:
BMS alarm sounds for a VAV
VAV unit inspected
Maintenance request created
Repair or replacement made
This reactionary model works but is inefficient. How long was the VAV malfunctioning before the alarm? How much energy was lost before? How long as it been affecting occupant comfort levels? How much time is required for all steps? How much energy, money, and comfort are sacrificed during downtime? These questions represent the issues inherent in the reactionary model.
FDD sees the problem before the inefficiencies start by using analyzing data from fault trends to predict failures before the actual alarm sounds. If a VAV is consistently running below specification, FDD can flag the activity as consistent with a failing terminal unit. That gives maintenance longer lead times and shortens downtimes.
Diagnostic algorithms like this basic one, move through a series of steps to detect and identify solutions to equipment failures.
FDD Systems Lower Energy Costs
With the growing emphasis on energy efficiency, FDD is becoming increasingly important as a tool for improving overall system performance and reducing energy consumption. Recent studies show that between 5% – 30% of commercial building energy is wasted due to problems associated with controls (Deshmukh 2018). So, FDD offers a massive opportunity to increase energy savings by finding faults faster.
One of the most common types of FDD systems used in buildings is Building Energy Management Systems or BEMS. These computer-based systems monitor and control the HVAC, lighting, and other building systems to optimize energy efficiency. BEMS often use temperature sensors to monitor the performance of an HVAC system and detect when the system is not working as efficiently as it should. The diagnostic algorithms then analyze this data and identify the specific problem, such as a clogged filter or malfunctioning compressor.
Predictive Analytics
Another important aspect of FDD is the use of predictive analytics. Predictive analytics uses historical data and statistical models to predict when a system is likely to fail. This enables building operators and maintenance staff to take proactive measures to address potential issues before they lead to costly downtime or equipment damage. Predictive analytics can be used in a wide range of systems, including industrial equipment, vehicles, and even wind turbines.
Furthermore, the use of predictive analytics can enable organizations to take proactive measures to address potential issues before they lead to a complete system failure.
Improving System Performance
While FDD is typically associated with detecting and diagnosing equipment failures, building operators can use it to improve system performance. By identifying and addressing inefficiencies in a system, organizations can improve overall system performance and reduce energy consumption. For example, an FDD system in an HVAC system might identify that the system is running at a higher temperature than necessary, resulting in increased energy consumption. By addressing this issue, the organization can reduce energy consumption and improve overall system performance.
In conclusion, FDD is an important tool for maintaining the reliability and efficiency of various systems. By detecting and diagnosing faults early on, organizations can take steps to address the problem before it leads to costly downtime or equipment damage.
After the former-company-known-as-Facebook rebranded itself in late 2021 to Meta, much of the world discovered the “metaverse”—the next generation of human connectivity that would fundamentally transform how we socialize and work.
According to Zuckerberg’s vision, the metaverse will be a place where social interactions are completely virtual, with self-created and customizable avatars interacting in ways that seem so real, we will easily take them as such. The new digital reality would affect work too, allowing workers to be at the “office” without leaving their home or changing out of their sweatpants. Remote workers no longer need to worry their physical office cohorts will race ahead, grabbing the next promotion or swanky project. Everyone would work in the same “space” regardless of their physical location.
The move to an immersive digital social life will certainly have massive implications for society, but building a new digital Agora for the modern world only scratches the surface of what the metaverse will be. That’s because its value extends beyond video games, social media, and the workplace. In fact, the sector to feel the most impact of these new virtual spaces will likely be today’s very real built environments.
Building Digital Twins
One key aspect of the metaverse for the built environment is the digital twin—a virtual doppelganger of a physical object or process. The notion of such a digital double is several decades old and the culmination of advances in 3D/BIM software, machine learning, and virtual technology. While architectural drawings have rendered 2D renderings of buildings for hundreds of years, 3D software added that extra dimension. Later, virtual reality would make the fourth dimension (time) possible. These advances set the stage for modeling physical processes like the human body or providing virtual walkthroughs of spaces like residential and commercial buildings.
However, digital twins serve a more important and practical purpose than visual mimicry; they attempt to model reality itself. To do this, digital twins must account for as many data points as possible. This includes every object, process and system that exists within a building—from the largest HVAC plant to the smallest occupancy sensor. All digital building systems function within a virtual world dynamically modeled to mimic the dimensions of time and space and natural forces. In short, the virtual world contains the same physical limitations as its physical counterpart.
The advantage of a digital twin, whether it be a building or an entire city, is that you can make changes and see what happens without doing it for real. This can be advantageous when time and costs are too great for real-life recreation or when impractical or impossible. Climate scientists, for example, use digital twins of the Earth’s weather systems to make predictions about the effects of global warming.
The more data points that make up your digital twin, the more accurate your simulations. In this way, data points function much like pixels that make up a screen, in that the more you can pack into a model, the higher the “resolution” and more life-like images you get.
However, such huge buckets of data take enormous amounts of computational power to process and manage. That’s where artificial intelligence and machine learning have helped give birth to the metaverse. Sophisticated algorithms do much of the “thinking” for us—locating patterns, making connections, running simulations and spitting out the results. Without them, modeling of systems is a rudimentary process, and it’s only relatively recent that we’ve been able to handle enough data to represent a virtual facsimile of complex physical processes and systems.
Helping Speed Up Building Decarbonization Adoption
As the metaverse takes its first steps, markets are already pricing in the tech’s potential to transform the built world. From a current global market size of $3.1 billion in 2020, experts project the digital twin market will reach $48.2 billion by 2026. Such growth is why some engineers, architects and entrepreneurs are looking to the metaverse and AI technology to help lower carbon emissions. In fact, an Ernst and Young study found that digital twins can reduce a building’s carbon emissions by half.
Founder and CEO of Cityzenith, Michael Jansen, oversees a digital twin platform that’s leading the push to decarbonize entire cities using metaverse technology. Recently Jansen hosted a live event laying out the current challenges to building decarbonization and how investing in digital twins can speed up green capital investments in the U.S. One pain point for property owners is retrofitting costs, which the CEO estimates at $4 to $7 USDs per square ft ($21 to $75 per sq m). “When you consider the fact that building owners spend about $2.10 per square foot on energy annually, it’s a large number,” Jansen states.
Another hurdle to building decarbonization adoption is the inherent conflict between the short-term gains investors demand vs the long-term investment that sustainable retrofitting requires. “The payback periods on typical [green] retrofits can be 10 to 15 years,” Jansen explains. “Those at the top of the investment pyramid typically look for returns within three to five years. As a result, a lot of these investments just don’t happen.”
While Jansen admits there are many challenges to green investment and adoption, he believes data is the obvious answer, at least for the short term. But buildings and cities contain thousands of software platforms, untold sensors, and BMS systems sending and receiving gigabytes of data through the air and over wires. It’s understandable that building managers can often feel as if they’re drowning in a sea of data and the digital tools that fill it.
Jansen claims it’s this “chaos of tools” that’s slowing building decarbonization efforts throughout the market. However, it’s understandable property owners would sidestep solving the issue of data glut, especially given the more immediate threats like higher construction costs, supply chain issues, swelling energy prices, and a shrinking demand for commercial office spaces.
Still, the Cityzenith CEO is correct in the assumption that funneling the increasing volume of data streams into a singular control is a desired outcome for most property and city managers. In fact, it’s this same consolidating impulse that’s motivating the move to integrated systems and open protocols within BMS technology today. Consolidation certainly increases data points, which is what digital twins need to be effective.
What’s needed is a “system of systems,” Jansen says. “The purpose of building a kind of metaverse around all of this…was to allow all these decarbonization processes to happen in one common place. So, all that activity could be studied and simulated before anybody actually spends a dollar. We use digital twins to predict energy consumption and financial outcomes to help drive down capital risk and increase adoption.”
Metaverse for Asset and Risk Management
While digital twins have numerous upsides for building decarbonization and efficiency, they can also help property owners and managers safeguard their investments. With aggregated data from building systems, equipment, and real-time sensors, digital twins can run physics-based models built on “what-if” scenarios.
Building and city managers can ask energy-related questions like “What if we bought 10% more solar and wind energy?” or “What if we generated more power on-site with roof-top solar array?”. After running such scenarios through a digitized property, owners would have a more accurate picture of the financial and operational impacts before committing. More importantly, they could easily tweak their input data until the outcomes fall within acceptable limits.
By using digital twins to accurately see future outcomes, property managers can also bolster their risk management. “What-if” statements can also apply to emergency situations like pandemics, natural disasters, and social upheaval. During COVID, many property owners scrambled to adjust to sudden lockdowns, indoor air quality demands, new hygiene mandates, and occupancy management challenges. Digital twin simulations of these variables could have better prepared owners and managers for the challenges while saving time, money, and possibly lives.
Sources:
“Cityzenith’s real world metaverse for decarbonization”. Published April 21, 2022, accessed April 28, 2022. https://youtu.be/l0L_7gwguoA
“Everything Facebook revealed about the Metaverse in 11 minutes”. CNET. Published October 29, 2021. Accessed April 26, 2022. https://youtu.be/gElfIo6uw4g
The social, environmental and technological challenges for the commercial real estate sector are significant. Many building owners and managers are still adjusting to the disruptions of the COVID pandemic, lock downs, remote working, mask mandates, rising energy costs and the move to hybrid work models. Few, if any, anticipated these events, nor the dramatic shifts they would kick start in building management and design.
On top of quickly developing social changes, there’s the long-term environmental impacts of global warming. Much of the planet is already feeling the implications of rising temperatures with increased flooding events, stronger storms, and eroding coast lines. All pose specific risks to property owners, since 10% of the world’s population lives in coastal areas that are less than 10 meters above sea level, according to an UN fact sheet.
Increased migration to cities and urban areas is spurring building development to a faster pace. The World Economic Forum estimates that two-thirds of the global population is expected to live in cities by 2050 and already an estimated 800 million people live in more than 570 coastal cities vulnerable to a sea-level rise of 0.5 meters by 2050. Technological advances pose yet another challenge to commercial real estate owners, as many feel the pressure by market competition and new government regulations to adopt energy and time saving building tech.
Given these social, environmental and technological challenges, it would seem change itself is becoming increasingly accelerated and unpredictable. Making things worse is the fact that we know less about the extent to which these factors affect each other. A warmer climate makes future pandemics more likely, which increases remote working, which reduces greenhouse gases. But higher temperatures also increase HVAC demand, which increases energy usage and greenhouse gases.
The entire system is connected, and each component poses a significant challenge in its own right; however, when combined, they will undoubtedly produce unforeseen outcomes that require quick course corrections at best, and entire paradigm shifts at worst.
While no one can predict the future, they can position themselves and their properties to better manage the unknown unknows. One way to stay flexible and adaptable is to adopt automated building controls built on open source protocols. Open building systems benefit from more technological flexibility, which can act as an important hedge against uncertainty.
Open System Protocols: A Short History
In the late 70’s early 80’s, large companies like Siemens, Johnson Controls and Honeywell took the first steps in connecting systems through electronic networks. Each brand developed proprietary “languages” or protocols that allowed building components like HVAC, lighting and alarms to “talk” to one another. While this created an efficient, dependable and integrated system, it also locked each property owner into the company’s proprietary hardware and software. And since connected systems were intended to last a decade or more, owners had little flexibility for innovation and change. In fact, it was the building systems provider that determined the speed and quality of that change.
Later in the mid to late 90’s, new organizations and companies like Tridium would introduce open protocols like the Niagara Framework, BACnet and LonWorks. These component languages didn’t limit owners to one brand by speaking one language. Instead, they could “interpret” between the other protocols, freeing owners to mix and match brands. Being “open” now meant property owners and managers could change the way they invested and used building technology.
Today, open protocols are a key play in helping evolve the next generation of automated building systems via IoT devices and smart building technology.
Open Systems and Adaptability
With open protocols, owners and managers can adapt quickly to market trends. With propriety systems, you’re locked into one manufacture’s software and hardware. Making upgrades or replacing components can be more costly than an open system. That’s because an open system is much like an open market. The more companies that compete for your business, the lower the price. Having the choice to shop around gives you budget flexibility to stay solvent sudden market fluctuations.
Quality is also affected. With open building systems, you can expand your search for new building systems and components outside a single contractor—who may or may not have the best quality available—and pick the best-of-breed tech. Component quality can vary based on priority, but open systems provide more flexibility for bigger investments. High quality investments are often long-term investments, so CAPEX projects also become easier to plan and deliver.
From a budgetary perspective, the best adaptability feature of open building systems is the ability to connect new devices to older systems. Open systems offer better ROI on legacy components. Building owners can realize their full technology investment by extending the life of older systems, while also adopting new solutions to keep them competitive.
Open source also makes it easier to customise your building systems. Non-proprietary protocols are valuable tools for developers and engineers to create bespoke solutions for the specific needs of their customers. Since connecting devices is easier, solutions are faster to develop, keeping you nimble and on-budget.
The Amazon “Biodome” campus in Seattle, Washington is a powerful brand statement about the company’s values.
Building Brand
Many of today’s biggest brands extend beyond their name recognition and marketing to include their physical properties. From Amazon’s Biodomes to Apple’s Spaceship, today’s corporate facilities and HQs are as much a part of the corporate brand as the logos themselves. But future businesses need not be on the Fortune 500 list to feel the necessity of such architectural recognition. Trends are already moving there fast, as post-pandemic attitudes toward workplace safety, air-quality and hygiene become part of a business’s social contract with its workers and communities. The safety and security occupants feel about a facility speaks volumes about those who own and lease its spaces.
In a recent episode of DCTV, Mitchell Day of Distech expressed the idea that a building is essentially a fundamental representation of a brand’s core values:
“A building is no longer just where you work,” he states. “A building expresses to the public who you are as a company, how you want [the public] to see how you see your employees and your products and who you want to be to the rest of the world.”
Day’s statement not only reflects the growing importance of facilities in general, but it also signals a shift in attitudes towards buildings as a core part of corporate responsibility. Today, brands feel more pressure than ever to adopt sustainable manufacturing processes, low-carbon footprint buildings, alternative energy sources and social responsibility. How a building functions, its efficiency and connectivity are indicators of that responsibility.
Open building systems offer the flexibility to adapt to cultural expectations. As Day himself says: “Open systems provide the power to give people more choices on how they express their brand.”
The Future is Complexity
It’s often said that buildings are “living” things, formed from complex systems working together to produce a habitable and safe environment for occupants. It’s an apt analogy, yet “complexity” is relative. With every passing year, emerging technologies like system integration, IoT, machine learning, smart tech and next gen sensors are making the dream of true system unification a reality. Tech is evolving at such a rapid pace it’s likely in a decade or two, today’s buildings may be likened to single-celled organisms by comparison. The entire “carpentered-world” will seem much more fluid.
While there are downsides to complexity to be sure, one of the biggest upsides is adaptability. The more complex, the more tools you have, and the more nuanced your approach can be. Complexity and connectivity are what property owners, and their buildings, will need to adapt to the challenges of future pandemics, energy transitions and global warming. Open building systems help building owners and managers manage such complexity.
Buildings are responsible for a significant chunk of emitted green house gases (GHGs) into the atmosphere. Therefore, they’re a leading contributor to global warming. In the U.S., buildings account for 40% of all U. S. primary energy and its associated GHG emissions. While these stats appear bleak, they actually represent a positive when it comes to FMs and owners. Because property owners and managers helm the ship of the Built Environment, they have the power to steer decarbonization efforts in the right direction. By adopting smart technology and building automation, property owners can significantly contribute to GHG reduction while saving money and futureproofing their investments.
With building decarbonization, small changes can make a big difference. Automating your after-hours HVAC program is an easy first step to reducing your property’s carbon footprint. You don’t need to take out a loan to invest in automation tech either. Online tools like cloud-based after-hours HVAC apps are inexpensive and simple to integrate with your existing BMS.
Cut Mistakes, Cut Waste
While after-hours request programs vary, the standard process works like this: the tenant fills out a work request for after-hours air conditioning or heating. Staff members record the request. The building engineer programs the HVAC to fulfill the request. The air con/heating is delivered at the require day and time. The property manager invoices the tenant at the end of the month.
Every step in this manual request process is an opportunity for errors to crop up. Forgotten emails, data entry mistakes and missed change requests are all more likely with a manual process. Mistakes cost time and energy, whether its extra lighting, access gates, lift rides or added HVAC service itself.
After-hours HVAC booking apps replace these manual step with wireless technology and network connections. Tenants create requests via a mobile or desktop app. The system then interfaces with the building’s BMS to schedule the request. The tenant, time and date are automatically logged, and the BMS delivers heating and air con on the requested days. By automating these steps, you cut out the wasted energy and help lower your carbon footprint.
Push Buttons vs. Cloud-Based Apps
Push button systems for activating HVAC service eliminate some, but not all, of the manual steps. They’re designed to deliver service as requested, giving tenants easy access to and control over HVAC operation. However, their openness can be a liability. Since anyone within the building can request service, savings from push button controls are often undermined by their public access.
There are no guards against everyone (ex. maintenance or cleaning staff) from accessing controls. So, unauthorized access can lead to unaccounted and wasted energy use. It’s also easy for occupants to “hit the button” minutes before leaving the room or floor, resulting in wasted energy from heating and cooling unoccupied spaces.
After-hours HVAC apps reduce energy waste by limiting access to the platform. In a cloud-based system, only authorized users can create HVAC requests. And the system records both the request and the requester. So owners always know who requests services. Plus, tenants can re-schedule and cancel bookings from anywhere there’s an internet connection. This helps save energy by eliminating empty room heating and cooling.
Data Equals Decarbonization
Automation goes hand-in-hand with data. Today’s smart sensors, IoT devices, machine learning, AI, digital twins, and BMS integration all point to the eventual integration of every building systems. In the near future, fire systems will “talk” with access systems to track occupants during an emergency. Access systems will work in tandem with HVAC systems to adjust heating and cooling demands based on occupancy levels. Building management systems will connect to utility providers to shift energy usage during peak demand. Such interoperability is already evolving, but it requires data to work properly.
By automating your HVAC requests, you can collect data on how and when your tenants are requesting HVAC services and use it to conserve energy. For example, you can identify seasonal trends and make targeted improvements and retrofits for specific zones of your property. Automation puts you in a better position to transition your property into a smart building and futureproof your assets.
Counting every kWh your property uses is important for your NABERS Energy Rating assessment. The more detailed your records, the more accurate your rating will be. Getting a true picture of your energy consumption means including and documenting your after-hours air conditioning (AHAC) service.
The NABERS Preparing for Office Rating Guide is a helpful resource for identifying what basic information to gather. But the guide doesn’t get into the specifics around documentation for AHAC. Documenting AHAC hours can be tricky given they’re usually tracked separately from normal operating hours. For a deeper dive, we recommend the NABERS Energy and Water for Offices Rules v.5.1. Although this resource is as a guide for assessors, it also provides valuable insights for FMs and property managers.
The Rules around AHAC are complex and hard to drudge through, so we’ve done the work for you. Below is a breakdown of the NABERS Rules for documenting AHAC, which will better prepare you for your assessment.
Rated Hours
NABERS assessors calculate the total number of hours per week your building is occupied—your rated hours. Assessors use your rated hours along with your annual kWh usage and other factors to determine your efficiency rating.
To calculate your rated hours, assessors will look at your core hours. These are your normal operating hours per week (e.g., 8 am to 6 pm). Core hours are usually listed within the owner/tenant agreement (OTA), and the assessor will likely use your OTA to help determine these.
To increase accuracy, assessors also include any AHAC hours. Your HVAC system uses energy to produce the AHAC service, so you should count these hours too. Any missing AHAC hours skew your total rated hour count, lowering your NABERS rating. And the impact will be proportionate to the total hours demanded. That is, the more AHAC hours omitted from your rated hours, the more inefficient your property will appear.
AHAC Documentation
The negative impact of omitting AHAC hours is why it’s critical to keep accurate logs of tenant requests. For NABERS, not just any records will do either. Assessors must deem data “acceptable” or else include it in the calculation. The NABERS Rules lists the following types of “acceptable data.”
Tenant Requests
Section 5.3.3.1 of the NABERS Rules addresses AHAC requests and states that “acceptable data” includes:
Logs of AHAC requests by tenants, showing the date and time of each request and the functional space to which it applied; and
Evidence of other AHAC requests, such as correspondence between the tenant and the owner or building manager or information written into the OTA which has been verified to be correct and up-to-date. This evidence must include the date, time and space to which AHAC has been agreed to be applied.
Therefore, an example of acceptable documentation might be an automated entry from an after-hours HVAC app that records date, time, floor and tenant. Unacceptable documentation might be a tenant email listing only the requested date and time. The most important part of accurate documentation is the tenant’s request, so keep this in mind when setting up your request process.
Overlapping Hours
To be considered rated hours, AHAC hours also can’t overlap with your core hours. So you’ll need acceptable documentation showing their separation. Section 8.3.2 of the Rules explains that to include AHAC hours, you must provide:
Evidence that no AHAC has been counted during the Core Hours and during the plant start-up period or the hour before the start of Core Hours if the plant start-up period is unknown;
One thing to note here: NABERS focuses heavily on counting only “comfort condition” hours— times when internal temps are appropriate for occupancy. Assessors assume that comfort conditions are not met during the start-up time for your plant. For that reason, you can’t count any AHAC hours that occur during start-up times for your system. If you can’t provide evidence of the actual run up times for temps, assessors will assume one hour.
Example: Your OTA lists your core hours from “8 a.m. to 6 p.m.” Your normal plant start-up time begins at 7 a.m. to reach comfort conditions. Tenant A requests AHAC from 7 a.m. to 8 a.m. on Wednesday, but your start-up time for Wednesday stays at 7 a.m. (i.e., AHAC and start-up begin at the same time). Since your building isn’t at “comfort conditions” by 7 a.m. on Wednesday, you can’t count that AHAC hour towards your rated hours.
Zones and Functional Spaces
To calculate AHAC hours, NABERS assessors also need to divide your net lettable area (NLA) into functional spaces— specific areas of your building. Functional spaces can be based on tenancy distinctions (i.e., leases) or physical ones (e.g. HVAC zones), but variations often happen. For example, multiple tenants could occupy the same functional space by leasing the same floor. In contrast, a single tenant might occupy separate functional spaces.
Regardless, the goal of defining functional spaces is to group areas with the same periods of occupancy so assessors can calculate the effects of vacancies and different operational hours on your building’s efficiency.
For facilities managers, the important thing to note is that AHAC requests need to reference their correct functional spaces. This is especially important when multiple tenants share the same functional spaces. Accurate records and detailed building schematics are essential, and assessors will use them to calculate your rated hours. To this end, Section 8.3.2 of the Rules requires documentation in the form of:
Drawings and measurements showing AHAC zones for requests serving different zones within a single functional space.
If the NABERS assessor can’t locate detailed areas for different AHAC zones, they will use the smallest area available or else average hours together. Either way, any guesswork will lower the accuracy of your rated hours.
The rules around multiple tenants sharing functional spaces and zones can get quite complex. So, read section 5.3.3 of the NABERS Rules to see what situation fits your properties the most.
Conclusion
The way your NABERS assessor handles your AHAC consumption will depend on several factors. One of those is how they arrive at your core hours. There are several methods for doing this, which depends on what data you make available. The assessor may determine your core hours from your lease. If data is missing, they may need to calculate an average, and when estimates are involved, you can bet they won’t likely benefit your rating. In the end, the key is proper and thorough documentation of your AHAC requests, HVAC zones, and NLA.
