ASHRAE Journal - March 2023 - 56

TECHNICAL FEATURE
FIGURE 4 The office heating and cooling setpoint and setback temperatures in the reviewed
codes. Absence of points on the graph mean setpoints are not specified (i.e., the equipment
can be turned off).
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Cooling Setpoint
Heating Setpoint
Cooling Setback
Heating Setback
specifications for interface usability and accessibility).
2. Update schedules and densities based on new field
data. Using extensive data from existing buildings (e.g.,
smart meter data, building automation systems, smart
phone tracking), occupant-related schedules and/or
densities could be updated. As an example, Abdeen,
O'Brien, et al.,17 used 1,000 homes of thermostat data
to show that household setpoints are several degrees
Celsius cooler than currently specified by the National
Building Code of Canada.
3. Require multiple occupant scenarios to be modeled.
Specific to the performance path of building codes,
it could be required that two or more occupancy scenarios
be modeled and that the average or least energy savings
versus the reference building be reported. In this
way, buildings would be more robust against uncertain
occupancy and would be better rewarded for adapting to
occupancy.
4. Increase occupant modeling requirements. In
contrast to the predominant schedule-based occupant
modeling approach, new requirements could be added
to better reflect reality. For example, rule-based models
could be required to define operable window use
and window shades. In doing so, the impact of building
design features on occupants' energy-related behavior
could be quantified more accurately (i.e., recognizing the
two-way interaction between occupants and buildings).
Ultimately, changes made to building codes should
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ASHRAE JOURNAL ashrae.o rg M A R CH 2023
improve the status quo, be feasible for practitioners
to apply, rely on consistent and replicable
procedures and be enforceable by officials.
The authors feel that the most advanced
occupant models in the literature, which
involve modeling actions of individual occupants,
are currently too complex for building
code purposes. For example, such models
are often stochastic-they produce a different
result each time they are run and require
many simulation runs to produce a meaningful
reference results range. However, the
authors believe that these recommendations
strike a good balance between complexity and
applicability to enhance the representation of
occupants in building codes.
One notable omission from most reviewed
codes is requirements for building usability by
occupants-for building systems and interfaces
to be available, intuitive, effective and accessible.
Ideally, building systems should easily allow occupants
to save energy. While some usability characteristics
may seem more relevant to safety-related requirements,
they are also important for energy performance. Systems
that are inconvenient or difficult to use are less likely
to be used in expected ways. A notable example of a
code requirement that involves usability is in ASHRAE/
IES Standard 90.1-2019.18 and National Energy Code of
Canada for Buildings,19 which both require light switches
be positioned so the user can see the controlled lights.
This is important so occupants receive feedback that the
light has been turned on or off as they use the switch.
Conclusion
This article provided an overview of a comprehensive
review of 23 building codes and standards worldwide
with a focus on occupant-related aspects. It showed
major discrepancies between occupant-related densities
(e.g., occupancy and plug loads) and rather significant
differences between schedules. The study also
found that occupants are treated in fairly implicit ways
rather than explicitly considering them as active agents
in buildings. While many building codes reward or
require specific occupancy-adaptive technologies (e.g.,
demand-controlled ventilation), few requirements
exist for usability of interfaces and building systems.
The article includes recommendations for how building
Temperature (°C)
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ASHRAE Journal - March 2023

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