Feeling Good with Daylight Harvesting

There are many intangible benefits of beautiful, blue sky days, such as inspiring our moods and enhancing our ability to differentiate true colors more accurately. Our positive attitudes under the bright light of the sun, as opposed to the gloominess we feel under an overcast sky, typically inspire us to creativeness, accomplishment, and possibilities. These characteristics are good guest mindsets for us as retailers.

Yet, how do we measure the return on investment (ROI) of a "feel good" benefit? The truth is, maybe we can't! Instead, we can more readily baseline and post-mortem our energy demand. In fact, to the extent that your energy manager has been using some form of usage-capture software over the past year or more, it is quite possible to pilot a daylight harvesting program immediately. By using a simple "standardization and normalization" process to reduce usage data to a correlative base, any resulting demand decreases can be directly attributed to your day-lighting efforts.

First off, I've participated in projects reaping about a 17-20% usage reduction in Arizona and California. These returns are typical for new construction, yet retrofits on some existing buildings can produce similar results, especially since existing demand data is more dependable than projected data.

There have been various combinations of strategies that should enable you to attain the 17-20% reduction range in the "sun" markets and even select other states. For example, one combination included active (sun-tracking) skylights with simple dimming ballasts, and a reduced design target for foot-candle lighting influence. There are many combinations, with a wide variety of investment considerations. Resources available to discuss design and post-mortem results include any of the popular lighting maintenance vendors, some specialty skylight vendors, or any member of the PRSM Green Council.

Payback periods for daylight harvesting are typically longer than simpler projects (lighting retrofits, for example), yet these are the projects that are the hallmark of a thorough "sustainability" program. Daylight harvesting projects are low-maintenance, high return projects that contribute to cash flow annually after breaking past the payback period. Important considerations for reducing paybacks on a daylight harvesting project include governmental incentives and rebates, and landlord/developer contributions. Again, the PRSM Green Council member or a lighting efficiency vendor member can offer guidance.

For smaller box retailers, front of box design can produce some day-lighting results when the store is exposed to sunlight. Even without skylights, a combination of clever transom design on the storefront with dimmable, separately-circuited lighting can produce a less expensive, simple day-lighting solution.

Finally, there has recently been a push by some landlords who require tenants to comply with its Leadership in Energy and Environmental Design (LEED) commitments. These landlords represent perfect partnering opportunities. Even landlords that do not pay close attention to LEED guidelines can be open to building skylights into the roof plan that could give them both rebate opportunities and/or additional investment by the retailer.

When developing a daylight harvesting project for presentation to your capital committee, make sure to consider all the possibilities. Once you've settled on an estimated ROI, Payback, and internal rate of return, try adding a sales "pop" related to guests "feeling good" within the sales area. This factor is truly an intangible, but with the right level of tangible benefits should be counted to push borderline projects into the approval bucket.

Wishing you the best of success in your greening efforts.  - The Green Council

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