Turn ’em Off or Leave ’em On?

Ever have this discussion with someone? Is it more energy efficient to leave lights on or turn them off?

Some speculate that the “start-up” energy it takes to turn on lights is more than it would take to just leave them on, others contend that of course you’d shut them off! Even if you’re just dodging out of your office to visit the WC?

The US Department of Energy weighs in:

Incandescent Lighting

Incandescent lights (or bulbs) should be turned off whenever they are not needed. Nearly all types of incandescent light bulbs are fairly inexpensive to produce and are relatively inefficient. Only about 10%–15% of the electricity that incandescent lights consume results in light—the rest is turned into heat. Turning the light(s) off will keep a room cooler, an extra benefit in the summer. Therefore, the value of the energy saved by not having the lights on will be far greater than the cost of having to replace the bulb.

Fluorescent Lighting

The cost effectiveness of turning fluorescent lights off to conserve energy is a bit more complicated. For most areas of the United States, a general rule-of-thumb for when to turn off a fluorescent light is if you leave a room for more than 15 minutes, it is probably more cost effective to turn the light off. Or in other words, if you leave the room for only up to 15 minutes, it will generally be more cost effective to leave the light(s) on. In areas where electric rates are high and/or during peak demand periods, this period may be as low as 5 minutes.

Fluorescent lights are more expensive to buy, and their operating life is more affected by the number of times they are switched on and off, relative to incandescent lights. Therefore, it is a cost trade-off between saving energy and money by turning a light off “frequently” and having to replace the bulbs “more” frequently. This is because the reduction in usable lamp life due to frequent on/off switching will probably be greater than the benefit of extending the useful life of the bulb from reduced use. By frequent we mean turning the light off and on many times during the day.

A 2008 article in Scientific American gives you license to turn off the lights:

A simple rule of thumb that balances both concerns is to shut off fluorescents if you’re planning to leave a room for more than five minutes, according to Francis Rubinstein, a staff scientist in the Building Technologies Department at Lawrence Berkeley National Laboratory’s Environmental Energy Technologies Division. Mary Beth Gotti, manager of the GE Lighting & Electrical Institute in Cleveland, agrees. For all practical purposes, “it almost always makes sense to turn the lights off,” Gotti says. “From an environmental standpoint, the best way to save energy is to turn off the things that you’re not using.”

Rubinstein notes that, even for fluorescents, the cost of electricity over a bulb’s lifetime far outpaces the cost of the bulb itself. “Even if you switch on and off a fluorescent light frequently,” he says, “the slight reduction in lamp life is a small effect relative to the energy savings you accomplish by being a good citizen.” Gotti adds that the reduction in lamp life from frequent on-and-off switching can often be counterbalanced by the extension of “calendar life”—the actual passage of time between lightbulb replacements—that results from using the bulb for fewer hours.

#4: Visit Your Local Library

The Daily Green shall be forgiven for calling us a “surprising” way to save money, it’s great that they included us in their best tips for “getting more out of life while helping the planet.” We’re #4:

“Instead of buying small mountains of books, CDs, DVDs and even magazines that you barely use, check materials out of your neighborhood library, or relax inside the quiet halls and browse on site. Over time, you can save a nice pile of cash, and you’ll help divert paper and plastics from landfills.”

New York’s Solar Thermal Roadmap

Renewable Energy World is reporting on New York’s plan to become a leader in the solar thermal landscape:

“By unveiling a solar heating and cooling programme that could create 25,000 new green jobs, generate US$2.6 billion in revenue and see 2 GW of new solar thermal capacity installed in the state over the next decade, New York has revealed its ambition to become America’s national leader in solar heating and cooling.”

New York Solar Energy Industries Association‘s Roadmap’s proposed implementation would save an estimated 6 million gallons of oil, 9.5 million ft³ of natural gas and displace 320 GWh of electricity production annually by 2020, translating into consumer savings of more than $175 million per year.

“13 Amazing Facts About Green Roofs” [The Daily Green]

13 Amazing Facts About Green Roofs: Green roofs and living walls offer many benefits, including cooling buildings, reducing stormwater runoff, providing wildlife habitat, growing food and creating jobs.

“Charge It”

The June 7-June 13, 2010 issue of Bloomberg Businessweek had an article called “A New Meaning for the Phrase “Charge It” alerting the business community to the demands electric cars will have for power:

“Two chargers are needed for each car” – one at home and one at work.”

There’s an iPhone app for drivers of electric cars to locate chargers.

People are reporting “range anxiety” – the fear of being stranded with drained batteries.

As President Obama and the car industry march forward with the push for lessening America’s reliance on foreign oil more and more drivers will be looking for a place to “charge it.”

What if public libraries across the country became known for having charging stations? Not a bad marketing idea eh?

If you are lucky enough to be planning a new building, major expansion or just redoing your parking lot consider integrating a charging station into your plans, your community may (eventually) thank you!

“Let Green Creep”

Check out two great articles that came out in May, one written by Louise Schaper, the other a Q&A with her:

Louise is the former (now retired) director of the Fayetteville Public Library (AK). She spearheaded one of the first LEED libraries in the country and in recognition of her achievements Fayetteville was named LJ Library of the year in 2005.

In the Let Green Creep article Louise speaks to the issue of greening operations, not just a facility. It is an important lesson to be “green all over,” to not let greening end once your building gets its certificate of occupancy but to really live green in a green building.