Would hallway lighting that uses motion sensors reduce costs in a 288 unit coop?

Asked by Alex Westin
Woodhaven, NY

We are looking to save energy and lower electricity costs in our co-op. We recently had an influx of young families and our electricity costs have skyrocketed. I was thinking that maybe we should replace our hallway lights, which are on 24 hrs a day, with some type of motion detection lights which are dim until someone walks by. Not sure if this exists.


David Bergman

Answered by David Bergman

New York, NY

David Bergman Architect

April 10, 2012

A fellow board member on my condo asked a similar question a few years ago when we were updating our hall and stair lighting.

Decades earlier, I had seen hallway lighting in other countries that turned off completely when no one was present, and thought it was smart, if a bit eerie. There was sometimes that moment of panic in an unfamiliar building: would I find the timed switch? Would I get my keys out before the lights turned off?

NYC's building code has been updated

More recently, my neighbor had come across lighting in Europe that was akin to what you’re describing and which had fewer of the (real or perceived) issues I recalled. Could we have that, she asked?

  • The answer, at the time, was no.
  • Fortunately, though, that’s not the answer now. NYC’s building code (see, I noted that you live in Queens!) has been updated with a bounty of green measures, some of which take advantage of new technologies to save energy.
  • Hallway lighting is one of the targets.

Lighting public egresses

Public egresses here used to have to meet a minimum level of wattage. Period.

That created a few barriers for those of us who wanted to increase energy efficiency.

  • For one, use of fluorescent lights was a fuzzy area due to the measurement of light levels by wattage rather than brightness.
  • Another was that there was no differentiation between occupied and unoccupied spaces.

So when we updated our lighting before the new rules, the best we could do was switch from old, relatively inefficient T12 fluorescent lights to better (and better looking) T8 fixtures. If I were doing it over today, the outcome would be a bit different – though the lights themselves might not be.

Occupancy controlled bi-level fluorescent lights

What I would recommend for my building today is pretty much exactly what you’re inquiring about: motion (or occupancy) controlled bi-level fluorescent lights.

  • When no one is in the hallway, the lights are on at a low level, enough to navigate if necessary.
  • Then they awaken when movement is sensed.

There are a few more relevant points to consider. Is there any natural lighting in your hallways? If so, you can now also use photometric sensors to turn down some of the lighting during the day. The old code didn’t allow that.

Also, code and insurance are likely to require that some of the lights have emergency backup power. These are handy not only for blackouts.

  • A ballast shorted out on one of our replaced lights recently, tripping the breaker for the entire stairway. (We have a walk up building so everyone uses the stairs.)
  • Fortunately, we had opted for the back up powered ballasts, which kept half the bulbs on at a diminished level until the electrician could replace the blown out (and very nasty smelling) culprit.
  • In the blackout of 2012, before we had the newer lighting, we’d had to gingerly climb the stairs in the dark for a couple of nights.

Saving money?

To return to your original question about whether new lighting and controls would save money, the answer is my typical fallback: it depends. In this case, it depends on what types of light sources you currently have.

  • If they are incandescent, well then there’s no question. Get rid of those toasters!
  • If they are older fluorescents like ours were, there’s probably no question there either because you’d be both increasing the lighting efficacy (that’s what they like to call it) and diminishing the lighting levels.
  • But if they are newer fluorescents, you might only be accomplishing the latter, and the cost of the lights and controls might then have a long payback period.

Either way, you may be able to qualify for government programs to assist with paying for the new lighting. Check out NYSERDA, the New York State Energy Research and Development Agency.

Young families increase energy consumption?

One thing I’m curious about: why would having more young families in your building cause the electrical consumption to increase?

I assume you’re talking about just the electricity for the co-op’s public spaces, not the apartments themselves, so we can’t blame it on excessive hours of video games.

The only thing I could think of might be the laundry rooms getting heavier use, but that alone probably wouldn’t account for the jump. Time to get some energy monitors maybe? Then you can crack down on those young whippersnappers.

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