Buildings play an important role in human life. Because of COVID-19, working from home has been becoming a popular alternative, leading to more hours spent in residential buildings. Being an adaptive approach in the era of COVID, working at home could face new challenges entangled with occupants’ satisfaction. One of them is the indoor environmental quality (IEQ) such as temperature, noise, air quality, and lighting. These indoor environmental factors have been examined to be associated with not only wellbeing, but also working and learning performance. Undoubtfully, occupants’ satisfaction with buildings is not confined to IEQ.
As researchers in the field of occupants’ satisfaction, we are striving to answer three questions for residential buildings:
1) What factors influence occupants’ satisfaction?
2) Are there specific types of residential buildings (e.g., LEED-certified) more satisfying?
3) For rental apartments, does rent price improve satisfaction?
What is LEED
Leadership in Energy and Environmental Design (LEED), developed by the non-profit U.S Green Building Council (USGBC), is one of the most widely used green building rating systems and aims to offer a sustainable and healthy building environment and awards buildings in locations that promote less vehicle travel distance and better liveability. A project pursuing LEED certification can earn one of four LEED rating levels — Platinum (>80 points), Gold (60-79 points), Silver (50-59 points), and Certified (40-49 points)—based on the total points earned across those categories. As of 2019, there are nearly 100,000 projects registered and certified LEED commercial projects.
Social media
The grand magnitude of data is publicly available as never before. Social media permits us to extract what occupants really care about and speak about their home, as opposed to responding to pre-defined questionnaires. It could reveal occupants’ attitudes on aspects not included in the pre-defined questionnaires. Another advantage of social media is its continuous data collection permitting longitudinal analysis.
In a recent study, we collected 8230 online comments for 232 LEED-certified apartments and 8531 online comments for 129 non-LEED-certified apartments from the most popular apartment rating websites. Through topic modeling and sentiment analysis using natural language processing (NLP), occupants’ topics of interest and satisfaction of LEED and Non-LEED apartments were investigated.
Occupants’ satisfaction with LEED and non-LEED apartments
In this research, we distilled 3 latent topics from online comments, namely “location and transportation,” “running cost,” and “health and wellbeing”. It is not surprising that “health and wellbeing” was discussed the most on social media as shown in Figure 1.
The heat maps in Figure 2 indicate that online reviews primarily focus on apartment management service, which is supported by the commonly appeared words (e.g., “staff”) based on frequency for both apartment types. Nevertheless, leisure facilities are discussed more often for LEED-certified apartments.
The sentiment analysis results, as shown in Figure 3, indicate that LEED-certified apartments have slightly higher satisfaction than non-LEED-certified counterparts for the 3 discovered latent topics. However, the enhancement is mostly negligible or small according to the calculated effect sizes.
For all IEQ factors depicted in Figure 4, the large distinction in satisfaction occurs for lighting only. It is observed that acoustics is the least satisfying while thermal comfort receives the highest satisfaction rate in apartments both with and without the LEED certification.
Impact of rent price on star ratings
Generally, people would expect to get services or products of equal or superior value to what they have paid. Thus, occupants’ satisfaction might be related to not only building characteristics (e.g., IEQ) but also rent price. To study how much satisfaction people can get for every dollar they spend, we normalized the star rating (from 1 to 5 stars) of each apartment by the rent price per room to monetize occupants’ overall satisfaction. As shown in Figure 5, the normalized star rating of LEED-certified apartments is not statistically (p= 0.073) higher than that of non-LEED-certified apartments.
In summary, LEED apartments are only slightly more satisfying than non-LEED ones in the three latent topics and occupants in the LEED-certified apartment are not statistically more satisfied as for the price they pay for the rent.
The study has been published in Building and Environment. For more details on the paper:
Guo, X., Lee, K., Wang, Z. and Liu, S., 2021. Occupants’ satisfaction with LEED-and non-LEED-certified apartments using social media data. Building and Environment, p.108288.
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