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: 419

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. 

Featured Forum Discussions

Glass Block Windows

Started by Ken Kalke in Best Practices. Last reply by Sean Lintow Sr on Saturday. 1 Reply

What's the Most Profitable HVAC Job for Your Company?

Started by Wayne Melancon in HVAC. Last reply by Ken Kalke on Friday. 1 Reply

Lighting replacement - 300 watt LED flood light

Started by Mary Sinkler in General Forum. Last reply by Eric Kjelshus on Friday. 1 Reply

EZ Green Home is Hiring!

Started by Chloe Chapman in General Forum Jan 5. 0 Replies

Videos

  • Add Videos
  • View All

Latest Activity

Profile IconMark Freeman and Bruce Fillmore joined Home Energy Pros
16 hours ago
Sean Lintow Sr replied to Ken Kalke's discussion Glass Block Windows
"Well as most I know (if not all) wont meet the energy code - none and for those that do opt…"
Saturday
Steve Gadsby posted a photo
Friday
Steve Gadsby commented on Perry Ning's blog post Warnings About Portable Air Conditioners
"We couldn't agree more about the problems caused by portable air conditioners. Here at Canada…"
Friday
Diane Chojnowski commented on Home Energy Magazine's blog post New Case Study: Arizona Leverages Industry Standards to Improve Home Performance Program
"Ted. I followed the link and found a place to download the Case Study on PDF:…"
Friday
Dale@EnergyWright commented on Joseph Burley's blog post Asbestos Shingle Nailpoint Debris
"I don't buy it. Shingles are typically pre-drilled and nails are pointy and wiped clean in the…"
Friday
Ken Kalke replied to Wayne Melancon's discussion What's the Most Profitable HVAC Job for Your Company?
"The most profitable would be residential and on equipment replacement. In the residential…"
Friday
Ken Kalke posted a discussion

Glass Block Windows

Hello, Just wondering how many home energy contractors are installing glass block widows. Our…See More
Friday

Home Energy Pros

Welcome to Home Energy Pros – the unique digital community by and for those who work in the home energy performance arena.

Home Energy Pros was founded by the developers of Home Energy Saver Pro (supported by the U.S. Department of Energy) and brought to you in partnership with Home Energy magazine.  Home Energy Pros is sponsored by the Better Buildings Residential Network. Please honor our Guidelines

© 2017   Created by Lawrence Berkeley National Laboratory.   Powered by

Badges  |  Report an Issue  |  Terms of Service