National Building Stock Study Reveals Ongoing Lighting Upgrade Opportunity

Below is my contribution to the December 2021 issue of tED Magazine, offering another take on the new Commercial Buildings Energy Consumption Survey recently published by the Department of Energy. Reprinted with permission.

Commercial buildings in the United States are trending larger and more commonly feature LED lighting and occupancy sensors. While traditional light sources have declined in use, they remain prevalent in the nation’s estimated 5.9 million buildings, spelling a significant continuing upgrade opportunity, particularly in older buildings that have not been upgraded.

These are just some of the conclusions drawn from the U.S. Energy Information Administration’s latest Commercial Buildings Energy Consumption Survey (CBECS), which has periodically profiled the national building stock since 1979 using a survey-based approach. Published in September 2021, the 2018 report provides estimates for commercial building characteristics such as region, activity, size, age, and equipment. It follows the 2012 report, which provides an historical benchmark.

In this article, we will dig into the data to produce salient findings in two key areas: commercial building characters and lighting and controls adoption.

Buildings

Between 2012 and 2018, the population of commercial buildings grew 6 percent to 5.9 million buildings, and total floorspace grew 11 percent to 97 billion sq.ft. During that time, 357,000 buildings and 7.5 billion sq.ft. were added to the national building stock. Since 1979, the amount of commercial floorspace has nearly doubled.

Other key findings:

• By floorspace, the largest markets were office, mercantile, warehouse and storage, and education. The most common commercial building types were warehouse and storage, office, and service, representing 48 percent of buildings and 42 percent of floorspace. While common, service buildings constituted only 7 percent of floorspace.
• The population of education, lodging, warehouse and storage, public assembly, worship, and service buildings increased. Other markets, such as office, healthcare, food sales/service, and mercantile decreased.
• The largest population of commercial buildings and floorspace was in the South Census Region. The second was the Midwest, followed by the West (populated by buildings of the largest median size), and Northeast (smallest population of buildings, oldest in median years).
• Newer commercial buildings tended to be larger than older buildings. In 2018, the median building size was 5,400 sq.ft., up from 5,000 sq.ft. in 2012. Seventy percent of buildings were 10,000 sq.ft. or smaller in 2018, down from about 75 percent in 2012.
• The largest buildings were a small fraction of the building population but a third of floorspace. Buildings larger than 100,000 sq.ft. constituted only 2.4 percent of the building population but 34 percent of floorspace. In contrast, the smallest buildings—1,001 to 5,000 sq.ft.—represented nearly half of buildings but only 8 percent of floorspace.
• The median year of construction for all U.S. commercial buildings was 1982, producing a median age of 36 years. Seventy-five percent of buildings were built on or before 2000, representing 71 percent of floorspace. Forty-six percent of all buildings, accounting for 41 percent of all floorspace, were built before 1980.
• A total of 86 million people worked in U.S. commercial buildings. This translated to a median floorspace of 1,175 sq.ft. per worker, a 14 percent increase in space over 2012.

Lighting and controls

Compared to the 2012 survey, the 2018 CBECS shows a remarkable technological shift toward LED adoption at the expense of traditional lighting. It also reveals growing adoption of automatic lighting controls, notably occupancy sensors. Nonetheless, the continuing prevalence of traditional and uncontrolled lighting produces a snapshot of a continuing market opportunity to upgrade older lighting systems.

Key findings:

• Adoption of LED lighting grew significantly between 2012 and 2018 in commercial buildings to become the second-most common light source. In 2018, LED lighting was used in 44 percent of commercial buildings and 64 percent of floorspace, up from 9 percent of buildings and 25 percent of floorspace in 2012. By 2018, LED was installed in 2.6 million buildings, more than five times more buildings than in 2012, and covered 62 billion sq.ft., more than two and a half times the floorspace. Looking at five major building types, adoption was highest in healthcare, mercantile, and office, as shown in Table 1.
• Standard fluorescent remained dominant but was in decline. In 2018, standard fluorescent lighting was used in 68 percent of commercial buildings and 76 percent of total floorspace, a decline from 84 percent of buildings and 92 percent of floorspace in 2012.
• Other traditional sources showed sharp declines in use. From 2012 to 2018, incandescent declined from 33 to 19 percent of buildings, compact fluorescent from 41 to 19 percent, halogen from 16 to 9 percent, and high-intensity discharge (HID) from 9 to 4 percent. In terms of floorspace, from 2012 to 2018, incandescent declined from 44 to 22 percent, compact fluorescent from 62 to 35 percent, halogen from 32 to 15 percent, and HID from 27 to 12 percent.

Table 1. Lighting equipment adoption in 2018 by major building type, expressed as a percentage of floorspace in that vertical market.

• Occupancy sensor adoption significantly increased. In 2018, occupancy sensors were installed in more than 44 billion sq.ft. in more than 1 million buildings, 26 percent more buildings than in 2012 and 24 percent more floorspace. In 2018, occupancy sensors controlled lighting in 17 percent of buildings but 46 percent of total floorspace, up from and 15 percent of buildings and 41 percent of floorspace in 2012.
• Adoption of other lighting control equipment was a mixed bag. Daylight harvesting increased from 7 to 7.5 percent of floorspace, increasing from 6.1 to 7.2 billion sq.ft. in 138,000 buildings, but remained flat at about 7 percent of floorspace. Building automation systems for lighting increased from 14 to 17 percent of floorspace, increasing from 12 to 16.7 billion sq.ft. in 317,000 buildings. Light scheduling remained flat at about 35 percent of floorspace. Multilevel lighting and dimming declined from 17 to 15 percent of floorspace, which is somewhat surprising due to the inherent controllability of LED lighting and its utility. Demand-responsive lighting significantly declined from 5 to 2 percent of floorspace. Look at the major building types in Table 2, however, adoption is nonetheless substantial for many of these equipment types in terms of controlled floorspace.
• Plug load control remained relatively rare. In 2018, for the first time CBECS included plug load control, which showed adoption in less than 1 percent of buildings and around 2 percent of floorspace. This is expected to increase due to this strategy being included in the latest generation of commercial building energy codes.

Table 2. Lighting controls adoption in 2018 by major building type, expressed as a percentage of floorspace in that vertical market.

While these adoption gains are impressive from an energy efficiency standpoint, inverting these numbers reveals a strong ongoing lighting upgrade opportunity, particularly in the lighting controls space.

Separately, CBECS estimated buildings and square footage that received a lighting upgrade as a renovation since 2000, around the birth of the LED revolution. Looking at buildings built since 2012, around when LED began achieving mass adoption in general lighting, 82 percent of buildings and 67 percent of floorspace have not received a lighting upgrade since 2000.

This number seems odd due to the significant adoption of LED, suggesting at least some form of upgrade has taken place. At a minimum, we can look to the continuing prevalence of traditional lighting, notably standard fluorescent still in the number one spot. If every standard fluorescent lamp were suitable for upgrade, this alone would represent lighting covering four out of five square feet in seven out of 10 buildings.

All of this leads to a simple conclusion that a substantial portion of the building stock remains untapped for LED and controls upgrades.

Check out CBECS

The 2018 CBECS is available for free online as XLS files at the Energy Information Administration’s website, offering insights into the building market that can be useful for business planning. How many warehouse and storage buildings are in the South? What is the average office floorspace per worker? In what building types is LED adoption greatest?

CBECS offers an estimate for these and many other questions here.

Craig DiLouie

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