ASHRAE Journal - January 2021 - 31
TECHNICAL FEATURE
a car, where user interfaces have
been extensively tested by designers and are generally standardized.
Imagine the havoc if the gas and
brake pedal positions in cars were
not standardized.
One of the authors lived in an
overseas university residence for
several months. Each suite had a
toggle button like the one shown in
Figure 3 outside the main doorway.
Given his past association with buttons outside homes, the author
assumed that this was a doorbell
of sorts. Accordingly, he didn't
dare push it, though he noted the
unnerving experience of navigating
the hallway in the dark. Months later
he discovered that the button was a
light switch that turned the hallway
lights on for 10 minutes before a
timer turned them off again.
Feedback and Mental Models
In most consumer products, the
interface is integrated and directly
connected to the rest of the system,
which means that the designer(s)
can optimize the interface for that
system (all seven parts of Figure 1).
In buildings, designers can mix and
match components; moreover, different professionals are normally
responsible for selecting different
components (e.g., interfaces, luminaires, HVAC, blinds, etc.). Technical
compatibility of components does
not automatically lead to a usable
building. In commercial buildings
particularly, we can add software
customizability to the list of components. Modern building automation
systems (BASs) allow technicians to
completely customize the control
logic. Moreover, digital interfaces
(especially those with touch screens)
can be customized-possibly by
people having no training in human
factors or feedback from dissatisfied
occupants. With this programming
power comes great room for failure
in usability.
In one academic building we
studied, three offices-each with a
thermostat-were grouped within a
single HVAC control zone. The system was designed to supply heating
to any office that required it, regardless of the effects on other rooms,
meaning that the thermostat with
the highest setpoint temperature
controlled the other offices' supply
airflow rate and temperature. As a
result, the other offices frequently
overheated, and their thermostats
had no effect on overheating. Given
the conventional layout of the thermostats in these offices, there was
a mismatch between the implied
control of allowing each office user
to adjust the setpoint and the real
control situation.
This mismatch, combined with
long thermal response times and no
instruction manual, inhibited occupants' ability to construct a functional mental model of the system.
Even the experienced researchers
with access to historical data and
the control logic took several hours
to figure it out. Karjalainen found
homes to be more comfortable than
offices and to have greater controllability, in part because occupants
understand residential HVAC
systems better than commercial
systems.5
Interfaces that promote useful
mental model development through
natural mapping (described next)
and clear and sufficient feedback
allow users to interact with and
learn system functionality. In many
cases, particularly with increasing
FIGURE 3 A light switch to activate hallway lights for
10 minutes.
trends towards advanced BASs, a
building's systems are complex and
difficult for the occupants to understand immediately. Therefore, users
need to be able to interact with the
system in an explorative way to learn
how they can operate the system
effectively.
Natural Mapping
A fundamental concept in usable
design is " natural mapping " : the
notion that interfaces and their
associated actuators should have an
intuitively correlatable geometrical
layout. It is normally up to the trades
to get this interface context (item 3
in Figure 1) right.
Don Norman suggests that the
best natural mapping is for the
interface to be physically connected
to the actuator.4 The next best is
geometrical congruence between
the interface and the actuator,
whereby the geometrical layout of
the interface features or interfaces
matches that of the actuator(s).
And worst is neither of these (e.g.,
Figure 4). For buildings, we don't
necessarily agree that the interface
should be connected directly to the
actuator because remote control is
JAN UARY 2021
ashrae.org
ASHRAE JOURNAL
31
http://www.ashrae.org
ASHRAE Journal - January 2021
Table of Contents for the Digital Edition of ASHRAE Journal - January 2021
Contents
ASHRAE Journal - January 2021 - Intro
ASHRAE Journal - January 2021 - Cover1
ASHRAE Journal - January 2021 - Cover2
ASHRAE Journal - January 2021 - 1
ASHRAE Journal - January 2021 - 1a
ASHRAE Journal - January 2021 - 1b
ASHRAE Journal - January 2021 - Contents
ASHRAE Journal - January 2021 - 3
ASHRAE Journal - January 2021 - 4
ASHRAE Journal - January 2021 - 5
ASHRAE Journal - January 2021 - 6
ASHRAE Journal - January 2021 - 7
ASHRAE Journal - January 2021 - 8
ASHRAE Journal - January 2021 - 9
ASHRAE Journal - January 2021 - 10
ASHRAE Journal - January 2021 - 11
ASHRAE Journal - January 2021 - 12
ASHRAE Journal - January 2021 - 13
ASHRAE Journal - January 2021 - 14
ASHRAE Journal - January 2021 - 15
ASHRAE Journal - January 2021 - 16
ASHRAE Journal - January 2021 - 17
ASHRAE Journal - January 2021 - 18
ASHRAE Journal - January 2021 - 19
ASHRAE Journal - January 2021 - 20
ASHRAE Journal - January 2021 - 21
ASHRAE Journal - January 2021 - 22
ASHRAE Journal - January 2021 - 23
ASHRAE Journal - January 2021 - 24
ASHRAE Journal - January 2021 - 25
ASHRAE Journal - January 2021 - 26
ASHRAE Journal - January 2021 - 27
ASHRAE Journal - January 2021 - 28
ASHRAE Journal - January 2021 - 29
ASHRAE Journal - January 2021 - 30
ASHRAE Journal - January 2021 - 31
ASHRAE Journal - January 2021 - 32
ASHRAE Journal - January 2021 - 33
ASHRAE Journal - January 2021 - 34
ASHRAE Journal - January 2021 - 35
ASHRAE Journal - January 2021 - 36
ASHRAE Journal - January 2021 - 37
ASHRAE Journal - January 2021 - 38
ASHRAE Journal - January 2021 - 39
ASHRAE Journal - January 2021 - 40
ASHRAE Journal - January 2021 - 41
ASHRAE Journal - January 2021 - 42
ASHRAE Journal - January 2021 - 43
ASHRAE Journal - January 2021 - 44
ASHRAE Journal - January 2021 - 45
ASHRAE Journal - January 2021 - 46
ASHRAE Journal - January 2021 - 47
ASHRAE Journal - January 2021 - 48
ASHRAE Journal - January 2021 - 49
ASHRAE Journal - January 2021 - 50
ASHRAE Journal - January 2021 - 51
ASHRAE Journal - January 2021 - 52
ASHRAE Journal - January 2021 - 53
ASHRAE Journal - January 2021 - 54
ASHRAE Journal - January 2021 - 55
ASHRAE Journal - January 2021 - 56
ASHRAE Journal - January 2021 - 57
ASHRAE Journal - January 2021 - 58
ASHRAE Journal - January 2021 - 59
ASHRAE Journal - January 2021 - 60
ASHRAE Journal - January 2021 - 61
ASHRAE Journal - January 2021 - 62
ASHRAE Journal - January 2021 - 63
ASHRAE Journal - January 2021 - 64
ASHRAE Journal - January 2021 - 65
ASHRAE Journal - January 2021 - 66
ASHRAE Journal - January 2021 - 67
ASHRAE Journal - January 2021 - 68
ASHRAE Journal - January 2021 - 69
ASHRAE Journal - January 2021 - 70
ASHRAE Journal - January 2021 - 71
ASHRAE Journal - January 2021 - 72
ASHRAE Journal - January 2021 - 73
ASHRAE Journal - January 2021 - 74
ASHRAE Journal - January 2021 - 75
ASHRAE Journal - January 2021 - 76
ASHRAE Journal - January 2021 - 77
ASHRAE Journal - January 2021 - 78
ASHRAE Journal - January 2021 - 79
ASHRAE Journal - January 2021 - 80
ASHRAE Journal - January 2021 - 81
ASHRAE Journal - January 2021 - 82
ASHRAE Journal - January 2021 - 83
ASHRAE Journal - January 2021 - 84
ASHRAE Journal - January 2021 - 85
ASHRAE Journal - January 2021 - 86
ASHRAE Journal - January 2021 - 87
ASHRAE Journal - January 2021 - 88
ASHRAE Journal - January 2021 - 89
ASHRAE Journal - January 2021 - 90
ASHRAE Journal - January 2021 - 91
ASHRAE Journal - January 2021 - 92
ASHRAE Journal - January 2021 - 93
ASHRAE Journal - January 2021 - 94
ASHRAE Journal - January 2021 - 95
ASHRAE Journal - January 2021 - 96
ASHRAE Journal - January 2021 - 97
ASHRAE Journal - January 2021 - 98
ASHRAE Journal - January 2021 - 99
ASHRAE Journal - January 2021 - 100
ASHRAE Journal - January 2021 - 101
ASHRAE Journal - January 2021 - 102
ASHRAE Journal - January 2021 - 103
ASHRAE Journal - January 2021 - 104
ASHRAE Journal - January 2021 - 105
ASHRAE Journal - January 2021 - 106
ASHRAE Journal - January 2021 - 107
ASHRAE Journal - January 2021 - 108
ASHRAE Journal - January 2021 - 109
ASHRAE Journal - January 2021 - 110
ASHRAE Journal - January 2021 - 111
ASHRAE Journal - January 2021 - 112
ASHRAE Journal - January 2021 - Cover3
ASHRAE Journal - January 2021 - Cover4
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_ATMAHK
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_VHQRAW
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_XGMDXI
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_YELQLJ
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_QJLWMC
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_MCDEBX
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_WNYSQY
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_XATVOD
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_FJSHSS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_CCBZDS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_XDEFVG
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2023november_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2023november
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_VHGNBL
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_WPKBNJ
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_UUVCDE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_RTGDEW
https://www.nxtbook.com/nxtbooks/ashrae/ashraemexico_2023
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_LKRFXS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_AZSOFG
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_ERCDBH
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_QWDFRV
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_JHGVDF
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_OPUYHG
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_SREIBM
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_LRTGLK
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_OKRFGH
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2022november_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2022november
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_TZSERA
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_LVRUIX
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_RPTVYZ
https://www.nxtbook.com/nxtbooks/ashrae/mini_pub_catalog
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_XIYTGD
https://www.nxtbook.com/nxtbooks/ashrae/ashraemexico_2022
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_RFGDOB
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_PABXNU
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_REMKLS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_PICVBT
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_AOYTVW
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_JQOPLS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_IOYTBC
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_SGAJJF
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_IGHYER
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_PDRKLS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2021november
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2021november_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_XCODFR
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_QSLFGO
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_ILKVNM
https://www.nxtbook.com/nxtbooks/ashrae/ashraemexico_2021
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_OPDJKD
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_VJKSRY
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_SDHUTC
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_JPPKRR
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_SDLTTH
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_CKLLES
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_SLDOX
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_HJETUK
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_OLUHGE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2020october
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2020october_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_ZERDGH
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_QVMNEO
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_RTPOKE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_BBATRE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_STUBMW
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_TPEMPE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_JNMKDS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_FBTTPA
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_WQMMNE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_TVBRYN
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_showguide2020
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_KTUZMA
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_ABEDGD
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201910
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201909
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2019septmeber_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2019september
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201908
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201907
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201906
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201905
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201904
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2019april
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201903
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2019march
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201902
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201901
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_showguide2019
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2018december
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2018november
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2018fall_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2018fall
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2018october
https://www.nxtbook.com/nxtbooks/ashrae/ashraemexico_2018
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201810
https://www.nxtbook.com/nxtbooks/ashrae/ashraeinsights_201806
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201805
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201804
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201803
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201712
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201711
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201710
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2017fall_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2017fall
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201709
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201705
https://www.nxtbook.com/nxtbooks/ashrae/ashrae_meetinginsert_201610
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2016fall_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2016fall
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_acrexindia
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2015summer_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2015summer
https://www.nxtbook.com/nxtbooks/amca/2014summer2
https://www.nxtbook.com/nxtbooks/amca/2014summer
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_acma_2014summer
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201311
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201309
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_acmasupp_2013fall
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201305
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201303
https://www.nxtbook.com/nxtbooks/ashrae/pubcatalog_2013winter
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201211
https://www.nxtbook.com/nxtbooks/ashrae/achr_expo_mexico2012
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201209
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201208_v3
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201208_v2
https://www.nxtbook.com/nxtbooks/ashrae/pubcatalog_2012summer
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201205
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201203
https://www.nxtbook.com/nxtbooks/ashrae/pubcatalog_2012winter
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201111_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201109_v2
https://www.nxtbook.com/nxtbooks/ashrae/pubcatalog_2011summer
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201105
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201103
https://www.nxtbookmedia.com