An article in the September/October issue of Home Energy, "Boosting Multifamily Energy Savings Through Lighting Control Settings" (page 38), has implications beyond dramatic savings in stairwells in apartment buildings. Ostensibly the article is about proper settings for motion sensors and the ideal "off-delay time," that is, the time the lights stay on before automatically switching off. The authors recommend that the lights should be set to switch off after only 30 seconds rather than the 30 minutes recommended by ASHRAE (see Figure 1). That's more than a 90% reduction! This isn't really a discovery because the stairwell lights in French apartment buildings have been using a delay-off time of 30 seconds for almost a century.

On the way to this recommendation, however, we learn that high-rise apartment buildings in the United States still lack any motion sensors in stairwells, hallways, and other public places. Many of those buildings are in New York City and cities with high electricity prices, making the potential cost savings especially attractive for landlords. While the energy savings are significant, the security aspects are really intriguing but are hard to value. An intruder can't hide in the shadows because the motion sensor will switch on the lights. If the lights are on, then somebody else is there. Thus, a well-controlled lighting system could even enhance security even though most of the time the area is darker than when someone is present.

Total darkness saves lots of electricity but it probably won't sell. That's why the future of public-area lighting is probably bi-level, that is, where very low illumination levels are maintained until somebody appears and the lights spring up to bright. These systems are now being installed in parking lots and garages. The Japanese have used manually-controlled bi-level lighting in offices and homes for decades but digital controls give this feature new advantages.

Figure 1. Effect on lighting with varying off-delay settings.

Next we learn that only a few manufacturers of lighting controls offer such short delay-off times. ASHRAE and other standards committees need to clarify that delay-off times of less than thirty minutes are acceptable. Indeed, changes like this will be essential if buildings are to achieve zero net energy targets.

In the future nearly all illumination in public areas will be controlled by a motion sensor, a light sensor, a clock, or be part of a network. The energy savings will be enormous. Will this future happen sooner or later? For it to happen sooner, the designers—and the installers—need to make these kinds of controls a desirable feature rather than an irritant.

I also want to call your attention to a second article in this issue, "How Net Zero Can Save New England Homeowners Thousands of Dollars" (page 30). That title (and conclusion) is based on data from real homes occupied by real people. The cost of building a low energy home and then pairing it with PV continues to fall as builders gain experience with both sides of the energy equation. To be sure, the analysis excludes some intangible costs and benefits—for example, I'd pay extra to live in a net zero home during a power outage—but the life cycle cost has already tipped in favor of the zero energy home.

- Alan Meier

Alan Meier is senior executive editor of Home Energy.

This article originally appeared on HomeEnergy.org

Views: 411

Comment

You need to be a member of Home Energy Pros to add comments!

Join Home Energy Pros

Comment by Chris Kaiser on September 9, 2013 at 10:42am

Alan, great post.  What also helps the adoption of sensors in these areas is the rise of LED lighting.  At Groom Energy, the majority of our projects for our commercial customers are LED lighting.  Unlike T5/T8 ballasts, LED life is not affected by turning the fixture on/off, so short cycle times are not the issue they are with T5/T8.  Even with a program start ballast, most fluorescent manufacturers wont recommend going below a 10/15 minute timeout.  With some of our LED installs we're going down to 30 seconds. 

Videos

  • Add Videos
  • View All

Twitter

Latest Activity

Profile IconBarbara Smith and Carl Johnson joined Tom White's group
Thumbnail

Weatherization

Share your concerns and successes as a weatherization professional, or information for this…See More
11 hours ago
Carl Johnson replied to Joel Greenberg's discussion The Truth About Windows? in the group Weatherization
"I think the appeal of replacing windows is largely on the aesthetics for most homeowners. Nobody…"
11 hours ago
Carl Johnson commented on Amber Vignieri's blog post Chicago Winter No Match for Retrofitted Logan Square Building
"Beautiful home! Did Josh replace the windows as well or no? Living in Chicago myself, I know about…"
11 hours ago
Carl Johnson commented on Diane Jackson's blog post Two Addison Projects Win Housing Innovation Awards
"These homes look great! Congrats!"
11 hours ago
Carl Johnson is now a member of Home Energy Pros
11 hours ago
Paul Scheckel posted a blog post

Renewable Rant: Traditional Energy!

Why, when I open up a newsletter or market evaluation report about “traditional energy” markets, do…See More
yesterday
Rob Madden, Solar Home Broker's discussion was featured

Indoor Air Quality Monitors and Meters

I'm considering purchasing the AirAdvice for Homes indoor air quality monitor but it seems to have…See More
yesterday
Luis Hernandez's discussion was featured

ERV Configuration

Greetings everyone,     I did an energy audit on this new home that is too tight and needs…See More
yesterday

© 2016   Created by Lawrence Berkeley National Laboratory.   Powered by

Badges  |  Report an Issue  |  Terms of Service