Understanding The Perceived Value of Using Bim For Energy Simulation
Understanding The Perceived Value of Using Bim For Energy Simulation
Understanding The Perceived Value of Using Bim For Energy Simulation
ABSTRACT
KEYWORDS
BIM, energy modeling, building performance, design stakeholder, perceptions
1. INTRODUCTION
An increased awareness of climate change, increasingly stringent building codes, and rising
energy costs are leading to a surge in global demand for better performing buildings, which
has invited designers to pay more attention to building performance. Applying sustainable
design principles can improve the overall performance of a building. However, difficulty exists
in knowing the exact implications of design changes on overall building performance or in
identifying interactive effects of such changes on individual building systems. In order to model
1. BIM Program & Project Technology Specialist, Procon Consulting, Arlington, VA 22201; email: alewis@proconconsulting.com
2. Associate Professor, Dept. of Construction Management, Colorado State University, Fort Collins, CO 80523 (corresponding author);
email: rvaldes@colostate.edu
3. Associate Professor & Assistant Director, Construction Engineering and Management, University of Colorado-Denver, Denver, CO
80204; email: caroline.clevenger@ucdenver.edu
2. POINT OF DEPARTURE
Building Information Modeling (BIM) is a process that utilizes a 3-D, parametric design soft-
ware that is capable of storing project information that can be updated and extracted by various
users. BIM is capable of demonstrating the entire life cycle of a building virtually. Building
Information Models (BIMs) are the virtual representations of a project that result from the BIM
process, which can act as a communication platform between project stakeholders (Mowata
and Carter 2013). BIMs are capable of representing the geometry, spatial relationships, geo-
graphic information, quantities and properties of building elements, and can be used to create
cost estimates, material inventories, and project schedules (Azhar 2011). Unlike drafting tools
such as AutoCAD, BIM allows for drawings to be completed more efficiently since it utilizes
parametric change technology and can have robust information embedded within the model
(Azhar et al. 2009). Parametric change technology maintains model consistency by allowing
users to create a single model, that when updated, automatically reflects the changes made in all
applicable model views. BIM also improves documentation reliability by providing a platform
3. RESEARCH APPROACH
3.1 Survey Instrument
An e-survey was developed based on past studies to determine respondents’ perceptions regard-
ing leveraging BIM for energy simulation while observing demographic data about respondents.
This survey allowed researchers to identify the factors that impact how green design stakehold-
ers’ engagement levels with BIM and/or energy simulation impacts their overall perceptions
of leveraging BIM for energy simulation. An extensive literature review and interviews with
design and construction professionals helped guide the development of the survey. During the
Firm Type
Design Related
Construction Related (Architects, Engineers, Energy
(Construction Managers, General Modelers, Energy Consultant,
Firm Size Contractors) Owner & Other)
Small firms Less than $25 million Less than $500,000
Small to medium firms $25 million to less than $100 million $500,000 to less than $5 million
Medium to large firms $100 million to less than $500 $5 million to less than $10 million
million
Large firms $500 million or more $10 million or more
In addition, the BIM Aptitude and the Energy Simulation Aptitude sections determine
which software products are used by each respondent’s firm. BIM and energy simulation soft-
ware programs were identified through an exhaustive literature review and through web searches.
The Energy Simulation Aptitude section goes a step further to gauge respondents’ perceptions
of the accuracy of their energy simulation results at predicting actual building operation usage.
The last section, How BIM and Energy Simulation Work Together, determines if respon-
dents use BIM models to inform their energy simulation(s) and if so measures respondents’
overall perceptions of using BIMs to inform energy simulations using a seven-point Likert scale.
Additionally, this survey section investigates respondents’ overall perceptions of the benefits
and barriers associated with leveraging BIM for energy simulation by asking them to what
degree they agree/disagree with a series of statements that pertain to the benefits and barriers
associated with using BIM for energy simulation. At the end of this section, respondents were
provided with a text box, so they may qualitatively describe additional barriers that may have
unintentionally been excluded of the survey instrument.
The authors acknowledge that the survey instrument has some limitations. The survey ques-
tions do not capture the description of how the BIM and energy modelers actually used BIM
for simulation. For instance, the survey did not ask which specific aspects of a BIM model were
used for the energy simulations (geometry only, data only, or both) or if any partial data transfers
were experienced due to interoperability issues. Thus, we can only infer if the respondents were
4. RESULTS
4.1 Sample
The sample population consists of green design stakeholders located in the U.S. that use BIM
and/or energy simulation software as a part of their job. For the purpose of this paper a green
design stakeholder is a person who holds an interest in the design of a project that is slated to
achieve greater levels of energy efficiency, produce less carbon and/or minimize environmental
impact more than an average building. The sample started as a convenience sample that was
then allowed to “snowball” to the contacts of those in the initial convenience sample. The initial
convenience sample (consisting of approximately 210) was gathered through a variety of chan-
nels including: academics, ENR’s Top Green Contractors list from 2011 and 2013, a contact at
BIMforum.org and a local sustainability consulting firm. Additionally, respondents were asked
to forward this survey along to any of their contacts who met the green design stakeholder
criteria. Including forwarded surveys, the number of respondents who received the survey is
estimated to be approximately 270.
A total of 85 responses were generated. However, a total of 34 respondent results were
removed from analysis because they were either insufficiently complete or because respondents
did not meet the criteria of green design stakeholders. The final survey sample size analyzed is
51. Based on a sample size of 51, which came from an estimated sample population of 270, the
response rate is estimated at approximately 19%. The breakdown of respondent firm types was
comprised of 35% engineering firms, 27% architectural firms, 20% general contracting firms,
8% other, 6% energy consulting firms and 4% construction management firms. As a whole,
respondents indicated that 43% of their work was comprised of institutional projects, 39%
commercial, 10% residential, 7% industrial and 1% other. Although respondents were located
Firm Type
Firm Size Construction Related Design Related
Small firms 1 4
Small to medium firms 0 18
Medium to large firms 2 13
Large firms 9 4
4.2 Analyses
A Cronbach’s Alpha test was run on both the BIM and energy simulation engagement indices
(broken down in Table 2) to determine how closely related the scale’s items (experience, exper-
tise, and implementation) were effectively determining the reliability of each scale. Both scales
were determined to be reliable, with a 0.638 and 0.765 Chronbach’s Alpha value for the BIM
and energy simulation engagement indexes, respectively. Engagement scores are measured on a
3–27 point scale (shown in Table 3). Of the 46 respondents that use BIM, engagement scores
varied widely with a mean score of 15.04 and a Standard Deviation (SD) of 6.13. Of all BIM
users, eleven fell into the low engagement level group, twenty-four medium, seven high and four
were very high. Similarly, of the 27 respondents that used energy simulation, the mean engage-
ment score was 15.85 with an SD of 7.66. Of all energy simulation users, eight fell into the low
engagement level group, seven medium, nine high and three were very high.
Energy Simulation
Engagement Score BIM Engagement Score
Perception of value BIM & energy –0.3034 (p 0.1698) 0.1498 (p 0.3205)
(PoV) simulation (n = 22)
BIM-only (n = 24) — 0.4377 (p 0.0324)*
TABLE 6. Breakdown of user group perception of Benefit items related to BIM-based energy
simulation.
TABLE 7. Breakdown of user group perception of Barrier items related to BIM-based energy
simulation.
5. CONCLUSIONS
The overall goal of this exploratory study was to determine what green design stakeholders
perceive as the main barriers and benefits to leveraging BIM for energy simulation and to deter-
mine how BIM and energy simulation engagement scores impact green design stakeholders’
overall perceptions of the value associated with using BIM for energy simulation. Correlating
green design stakeholder perceptions on the value associated with BIM-based energy simula-
tion and BIM and energy simulation engagement scores allows researchers to observe and test
if engagement with either (or both) tool is likely to increase their perceptions of BIM-based
energy simulation. Specifically, a positive correlation of 0.4377 was found between the overall
perception of the value associated with using BIMs to inform energy simulation and their
BIM engagement scores for BIM-only users. This correlation might indicate that as BIM-only
users become more familiar with using BIM they may perceive higher levels of value associated
with using information from BIMs to inform energy simulation, which may be because they
become more confident in their ability to construct better models. However, BIM-only users
may not know exactly what information energy modelers require from BIM models and may
be overly confident in their model’s usefulness for energy simulation purposes. Greater training
and education along with creating a feedback loop with downstream energy simulators may
help alleviate issues that arise from modeling over confidence.
Based on the responses, green design stakeholders’ overall perceptions of the value associ-
ated with using information from BIMs to inform energy simulation were between neither low
nor high value and somewhat high-value with a mean score of 4.39. Although not statistically
significant, when comparing distinct user groups within the respondent pool, BIM-only users
had the highest average perception of value associated with using BIM to inform energy simu-
lations (mean of 4.88), while those who only used energy simulation had the lowest (mean
of 3). BIM-only users also have the highest perceptions of an energy simulation program’s
ability to accurately predict building performance with a mean value of 4.87. This comparison
suggests that BIM-only users may have overly optimistic expectations of the capabilities of
energy simulation.
It was also found that different user groups’ perceptions of the greatest benefits and bar-
riers associated with using BIM-based energy simulation varied considerably for some items.
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