New Survey Suggests Typical Lighting Control Energy Savings in Office Buildings

The Lighting Controls Association authorized ZING Communications, Inc. to conduct a survey of a group of nearly 900 lighting designers, more than 730 electrical engineers and more than 530 lighting/energy consultants subscribing to the LightNOW lighting industry and lightingCONTROL lighting control e-newsletters. The survey, conducted online based on three email invitations distributed in December 2008 and February 2009, produced a 6% response. Of this response, 95 respondents qualified to complete the survey, an overall 4.4% response.

lca1

The survey covers advanced lighting controls in the office building new construction and existing buildings retrofit markets, asking respondents to indicate how often they specify certain strategies, how they perform, whether energy savings are verified, and if so, how much energy they save on average.

Note that this is not a universe study. The results should not be attributed to the construction industry overall. The respondents, by virtue of their interest in lighting controls, subscription to lightingCONTROL, and their interest in and ability to complete a very detailed survey about lighting controls, suggests that they are in the high end of the lighting controls market. This introduces a bias with some of the results. For example, their satisfaction with controls may be higher than other construction professionals because they may design control systems better than their competitors. The data point that is most transferable across the market is average energy savings realized for certain control strategies.

How often are advanced controls specified and installed?

The subscribers divided themselves into two groups—those who focus on new construction, and those who focus on retrofits. They were asked to report the percentage of new construction or retrofit office building projects over the past two years for which they specified certain control strategies. They were then asked the same question, but concerning projects in which the controls were actually installed, not just specified. All resulting numbers are rough estimates (+5%), as respondents were asked to express their answers as a range (1-10%, 11-20%, etc.), which were defaulted to the middle as an assumption (5%, 15%, etc.). The numbers suggest rates of adoption for new construction and retrofit office building projects and substitution rates.

The results suggest that for new construction projects, occupancy sensors and bilevel switching are the most popular lighting control strategies. It is encouraging to see that the most progressive controls specifiers are specifying personal dimming control for one out of five projects, and the substitution rate, while higher than the other strategies, is still reasonable. The data appears to confirm that daylight harvesting is becoming more popular. However, there was one surprise: Occupancy sensors and scheduling controls would be expected to be installed in more projects.

lca2

How often are advanced controls specified and installed into existing buildings?

The results suggest that for office building lighting retrofit projects, occupancy sensors and bilevel switching are the most popular lighting control strategies. The level of adoption of bilevel switching in existing buildings is surprising given the added cost and difficulties to the project. Bilevel switching is required by the Commercial Buildings Deduction, which may be more influential in office building retrofit projects over the past two years than we had supposed.

lca3

Do specifiers regarding lighting control strategies as relatively problem-free?

Subscribers were asked to rate various lighting control strategies on a 1-5 scale based on how problematic the installed controls were during operation. A 1 indicated the installation was very problematic, a 3 somewhat problematic, and a 5 indicated that the controls are problem-free. No control types were identified as particularly problematic. These results are were expected.

lca4

Why do specifiers specify advanced control strategies in their office projects?

Subscribers were asked to rate various reasons to specify advanced control strategies on a 1-5 scale based on their significance. A 1 indicated the possible reason is very significant, a 3 somewhat significant, and a 5 very significant. Energy codes and energy cost savings are identified as very highly significant as drivers to specify, which is not surprising. One interesting result is the importance of LEED and sustainability, identified as very significant (>4.0 rating), almost as significant as energy codes and energy cost savings.

lca5

How often is the energy savings performance of office lighting control projects verified using monitoring or some other method?

Respondents were asked to identify the percentage of their office projects that include automatic lighting controls and in which energy savings were verified using monitoring or some other method. Nearly one-third of respondents said this occurs on their projects—an estimated 22% of projects, based on a weighted average of the responses with a +5% margin of error. These subscribers formed a subgroup to which another question was asked, which was to identify average lighting energy savings resulting from popular automatic lighting control strategies.

lca6

How much lighting energy savings do popular automatic lighting control strategies produce?

Respondents were asked to identify average lighting energy savings resulting from installation of popular automatic lighting control strategies, as measured in their verification projects. All resulting numbers are rough estimates (+5%), as respondents were asked to express their answers as a range (1-10%, 11-20%, etc.), which were defaulted to the middle as an assumption (5%, 15%, etc.). The numbers suggest typical energy savings for popular lighting controls. Personal dimming control was eliminated due to insufficient data sample that was producing a suspicious result (25% energy savings, much higher than previous research).

The results for the remaining control types contradict conventional wisdom in the case of occupancy sensors, which were expected to be higher (around 35-45%), and scheduling controls, which were expected to be lower (around 5-10%).

lca7

Do verified energy savings meet or exceed specifier expectations?

Respondents were asked to rate how well various control strategies installed in their office projects over the past two years met their energy savings expectations on a 1-5 scale. A 1 indicates it did not meet expectation, a 3 that it met expectations, and a 5 that it exceeded expectations. Occupancy sensor, scheduling and daylighting control strategies were ranked very highly by respondents. Personal dimming was eliminated due to insufficient response.

lca8

6 Comments

  1. [...] Among new building projects surveyed in the past two years, occupancy sensors were recommended to be installed in 55 percent of applications, according to a recent survey. [...]

  2. Al Lewandowski says:

    Bi-level is such a waste and has been the typical type of lighting in schools and universities for 40 years so I do not know why you think this is something new. In fact various studies have shown in the “real world” that instructors and students tend to hit all the switches for they do not know or care which one lights what.

    Please keep that in mind, the rest of your study is plausible but bi-level is not a energy conservation tool!

  3. Craig DiLouie says:

    Hi Al, welcome and thanks for your comment.

    Bi-level switching is of course not new but research tends to support it as a rather simple, basic but working energy conservation tool in its own right (not to mention it being mandatory in IECC). One study by ADM Associates showed energy savings of 22% (if my memory serves me) in private offices. Overall, bi-level switching is simply another tool that has its applications. What’s really interesting is a recent CLTC study combining bi-level switching and occupancy sensing in private offices, which showed that combing bi-level switching and a manual-ON occupancy sensor generated 46% more energy savings than if an occupancy sensor was used alone.

  4. [...] New Survey Suggests Typical Lighting Control Energy Savings in Posted by root 6 minutes ago (http://www.lightnowblog.com) Do specifiers regarding lighting control strategies as relatively comment rss trackback powered by wordpress and plainscape theme Discuss  |  Bury |  News | New Survey Suggests Typical Lighting Control Energy Savings in [...]

  5. Barbara says:

    Did you happen to ask about the ROI of the sensor methods, or the % of square foot of deployment by space type? It may be time to break these spaces into smaller increments based on functional use so that accurate estimates can be made.

    One concern is the cost of installing a sensor, when it includes the requirement for bringing in electrical, takes this option out of the 2 year ROI requirement often found in commercial buildings.

    The same issue is brought up when the lights have to be retrofit from on/off to dimmer ballasts – again, the ROI is far longer than desired.

    Finally, I appreciate this study, even while recognizing that this is a survey of “interested parties” and may not reflect the opinions of the owners.

    Specific case studies, or at least a detailed discussion of the constraints and attributes of a good candidate for each type of light change would be very helpful.

  6. Barbara says:

    Thanks for this discussion.

    Did you happen to ask about the ROI of the sensor methods, or the % of square foot of deployment by space type? It may be time to break these spaces into smaller increments based on functional use so that accurate estimates can be made.

    One concern is the cost of installing a sensor when it may include the requirement for bringing in electrical. Often these combined costs do not meet the 2 year ROI ceiling often found in commercial deployments.

    The ROI concern appears again when the lights have to be retrofit from on/off to dimmer ballasts.

    Finally, I appreciate that the authors recognize that this is a survey of “interested parties” and may not reflect the opinions of the owners.

    Specific case studies, or at least a detailed discussion of the constraints and attributes of a good candidate for each type of light change would be very helpful.

Leave a Reply