Vista Window Film
Vista Window Film greenbldgs
Twitter - join the conversation


Commercial Window Films rss RSS email E-MAIL

Residential Window Films  rss RSS email E-MAIL

Over-Lighting: A Barrier to Energy Efficiency

May 5, 2015 | 2 comments

With computers and tablets impacting the way we work, recommended indoor lighting levels have changed. As a result, lighting intensity levels in some commercial buildings are now higher than what’s necessary or appropriate for specific work-related tasks.

Beyond wasting energy and hindering efficiency efforts, over-lighting a commercial building can adversely affect tenant and occupant health. Indoor lighting that is too intense can cause headaches, fatigue, stress, and anxiety. Some research indicates that it can also impact natural circadian rhythms.

Over-illumination can also cause your building’s HVAC system to work harder as it compensates for the heat given off by artificial lighting. This uses excess energy, and causes wear and tear on your cooling system. As the system runs for longer periods of time – and more often – equipment lifecycle may be impacted.

So what’s causing over-lighting in commercial buildings? According to JLL, older lighting systems may be a big contributing factor. Originally intended for paper-based reading tasks, overhead lighting systems used to be designed with lighting levels between 750 and 1,000 lux. But the Illumination Engineering Society (IES) now recommends that overhead lighting levels fall between 300 and 500 lux in open office spaces. In areas that aren’t used as often, such as hallways and stairwells, 50 lux is recommended.

A light meter can measure your building’s current lighting levels. Once you compare those readings to the standards set forth by the IES, you’ll be able to determine whether your building is over-lit.

One way to reduce lighting levels is to eliminate unnecessary fluorescent lamps (delamping). By removing lamps and disconnecting ballasts in over-lit spaces, you can save energy while still providing enough artificial light.

Artificial overhead lights may also be dimmed or turned off to avoid unnecessary energy consumption. In fact, a collaborative study between the California Lighting Technology Center and the California Energy Commission PIER Program found that using LED task lighting as the primary source of lighting in offices may result in major lighting energy savings as well as improved occupant satisfaction.

If tenants and occupants have access to ample daylight, make sure it’s being taken advantage of – but also realize the potential problems associated with uncontrolled sunlight. When blinds and shades are opened to allow natural light in, glare and solar heat gain can negatively impact comfort, productivity, and satisfaction levels. High-performance, low-e window film can help reduce glare and control solar heat gain to keep interior temperatures comfortable.

Installing occupancy sensors can also help control the problem of over-lighting by making sure lights aren’t on in unoccupied areas (closets, restrooms, private offices, etc).

When was the last time you checked the lighting levels in your commercial building? Is your building over-lit?

Image from: vorakorn


  1. Jane Fox
    July 14, 2015

    I never thought about how a business could be over-lit. I used to work in an office where we had lots of windows, and I think we really didn’t take advantage of the natural light like we should have. Now, however, I’m in a much more closed-off building. We’re looking into revamping our commercial lighting, and I’m wondering if you have any suggestions. You suggest removing unnecessary fluorescent lamps, but is there a system you think we should look at?

  2. Vista
    July 23, 2015

    Hi Jane, glad you found this helpful! The easiest thing to do would be to get a light meter to measure lighting levels, and then compare your results to the standards set forth by the Illuminating Engineering Society. That will tell you if you are, in fact, over-lit!

Leave a Reply