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Chris Irwin | 17 Mar 2020

How Comfy are your Building’s Occupants? Part 2

In Part 1 of our blog series on occupant comfort, we explored what occupant comfort means and why it's important. Now that we've laid the groundwork, we will discuss how Building Automation Software (BAS) addresses, measures, and manages these seemingly subjective factors to increase occupant comfort and thus productivity. 

Building Occupant Comfort Part 2

Increasing occupant comfort with BAS

As discussed in Part 1 of our series, there are multiple factors to consider when it comes to occupant comfort: aesthetics, lighting, acoustics, air quality, temperature, office furniture and quality, desk management, and overall satisfaction. Here's a look at how building automation systems can have an impact on each of these, making it easier to improve and control occupant comfort in your building. 

Aesthetics 

The aesthetics of your building sets the stage for the type of environment you have. The colors, design elements, and layout can all have impacts on occupants. One aesthetic that can be controlled by BAS is your window treatments. Smart glass or electrochromic glass is an alternative to window treatments or blinds that allows occupants to experience the beauty of the outdoors while not being hindered by the sun. As mentioned in Part 1, incorporating nature into your environment can have positive effects. Smart glass can actually tint on-demand, allowing occupants to experience the natural world outside or block the brightness and heat from the sun when necessary. 

Lighting

Lighting can have effects on mood, focus, alertness, productivity, and circadian rhythm; making your choice of lighting systems important. Your BAS can do more than save energy by controlling usage. With smart lighting, you can control the light level based on occupant activity, or the spectrum of light emitted adjusted to mimic the natural cycle throughout the day. These seemingly minor details can have huge impacts on your building occupants' well-being and productivity.

Air quality

Poor indoor air quality has been tied to multiple occupant health issues - and can actually increase frequency of absenteeism. In order to have good air quality, you need to have proper ventilation. The problem with modern buildings, however, is that we continue to make our buildings as insulated as possible to control temperature and thus energy usage. Well insulated, super air-tight buildings don’t have natural ventilation, so in order to maintain air quality, we have to design a system that brings in fresh air to control indoor humidity and airborne contaminants. Your BAS can play a huge role in managing air quality by controlling your HVAC ventilation rates. Do this most effectively direct measurement of air quality, both CO2 and particulate concentrations are necessary. As historically few buildings were fitted with these, because it wasn’t seen as a priority and the sensor cost was high, there is now an opportunity to retrofit these, since their cost has fallen and wireless types are now available too. One challenge of adding such sensor networks to the BAS is integrating the data so that the BAS can use it to optimize the ventilation strategy. Open framework software makes this relatively easy.

Air temperature/humidity 

Modern Building Automation Systems offers very accurate direct digital control (DDC) that is able to maintain setpoints for both temperature and humidity within a +/-0.2 degree and +/-2%RH, provided the HVAC equipment is well-designed and adequately sized. Human comfort is attributable to a variety of factors that need to be in alignment. A more subtle, but equally important relationship in comfort is when temperature and humidity combine to create a “comfort index”. This means that a dry, low humidity environment can feel cooler for the same temperature than a higher, relative humidity. BAS controls have the ability to take into account this fact and utilize comfort index setpoints to help maintain the proper air temperature and humidity levels. 

Measuring Occupant Comfort

As you can see from the above examples, your BAS plays a huge role in occupant comfort. But how do you tie-in metrics to measure something that seems so personal and subjective? Here are some metrics to consider. 

Acceptability Index Value

The Acceptability Index Value (AIV) is the ratio of a building’s Energy Utilization Index (EUI) and occupant acceptability. The formula is AIV = EUI/OA and it helps evaluate the effectiveness of energy use to achieve a specified percentage of occupant acceptability (OA). 

Your building EUI is a measure of the total energy consumed in the cooling or heating of a building or facility in a period expressed as BTU (British Thermal Unit) per (cooled or heated) gross square foot, or as the metric equivalent - KW per square meter.

Occupant Acceptability (OA) is determined through surveys of occupants. Your OA is the  average response percentage of occupants whose average response is that the environment is “acceptable.”

You can read more about the metric here.

Measuring performance

In addition to measuring occupant response or comfort, you should also measure its effect on performance through measurable and controllable parameters and values. This will, of course, vary in the type of work your occupants are doing, but some examples include the quantity of work submitted during a specific unit of time, number of calls processed, number of absences, or other performance metrics you usually monitor. Taking note of performance metrics and then cross-referencing with occupant acceptability and building metrics will help you determine how the changes you’ve made to the environment are affecting performance and ultimately your bottom line.

Pulling it all together

Your BAS likely provides traditional metrics on the operational performance of equipment,  but how do you pull in occupant comfort surveys and metrics to better fine-tune your building’s function and better address occupant needs? You can use a tool like Comfy that combines data about the building with real-time data from people to help maximize space utilization, reduce energy consumption, and increase occupant comfort.

Comfort levels have a direct impact on productivity, employee retention, and well-being - all factors that affect the bottom line when the costs of absenteeism, health insurance, and employee attraction & retention are factored in. Many of these factors can be controlled by well-designed building automation software, which can integrate the various data sources and provide flexible dashboards, analytics, and reporting. 

See here for more on building comfort 

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About the author

Chris Irwin