# Controls or Not for Lighting?



## Cletis (Aug 20, 2010)

I'm trying to figure out if controls on lighting such as (occupancy sensors, daylight harvesting, dimming etc..) really saves large or much money when you take into consideration the whole cost of job with installation, maintainance, replacement, labor. Seems like the big companies just show you the savings but not the double installation costs and all those other factors involved. 

For example just a basic 100,000 sq ft faciltity that works 12 hrs a day with say induction dimmable high bays at 24 ft. Let's say they have 20 or so Solotubes as well. How about 0.09 / KWHR Seems to me the controls would be a waste in this application..but what do I know.

Any thoughts? 

I've been staring at Walmarts, Stadiums, Cold Storage, Processing Plants, Grocery Stores etc.. lately and all the ones with recent installs even with same application have different stategies? 

I do like the company graphit's site. They have some neat controls.


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## Lighting Retro (Aug 1, 2009)

tough to answer that question without more details actually. 

You are right that the installation for some of these solutions can double, so it must show a payback or it's not worth it. For instance, if a warehouse has tons of isles that have very little use, they may be great candidates for sensors. We typically order them on each fixture where appropriate, and we have the customer tell us what percentage of time they will be unoccupied so our numbers are "real" in their mind. 

For instance, if you have a 100,000 warehouse, but the only picking that goes on is for 8 hours of the 24 hours 5 days a week the warehouse is running, but the circuits are run in such a way that you can't turn off those areas, they may benefit greatly and be able to EASILY justify the cost of the sensors. 

If the warehouse had several rooftop skylights next to where high bays were, or if you had an office with large open windows where daylight harvesting would be of benefit, you still have to run the numbers of potential savings vs. the additional cost of dimmable ballasts and sensors. Future troubleshooting and repair should also be a consideration unless you are offering a maint contract. 

I have noticed several of the newer Walmart's with dimmable ballasts just around their skylights, and the sensor covers several fixtures at once. 

Some places want this technology because it's cool or neat to say they have the gadgets, but we try not to recommend things that show no payback. To me it's like putting a motion sensor in a storage closet that is opened once a week and usually has the light shut off. There usually just isn't a decent enough savings for me for one fixture to want to sell it. You only save money when the light is off compared to when it is usually on. Some people want it anyways, so it's best to explain ROI periods. 

EX: "Your overall project is a 24 month payback, but these solutions I'm showing you typically have a 36 month payback for themselves. What this means is that overall, your total project payback goes from 24 months to 25.7 months, but you get the additional features that they provide, and you will save "x" more dollars down the road per month/yr, etc". 

Cost is usually not as relevant as the payback period in our experience. People want what they want, and if it pays for itself in a reasonable time frame, then it is more desirable mixed in with standard solutions vs. as a stand alone solution. Ask them what they are expecting for a payback period or if they have a threshold they want to stay within.


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## LightsRus (Sep 12, 2010)

This matter was summed up very well by Lighting Retro.

You must somehow calculate how much the occupancy and photo sensors reduce the ON time of new lighting. That may require an elaborate spread sheet to include lighting banks with and without sensors.

We have revised some of the terms in our ROI calculator to address any lighting, and have highlighted a note for the one entry affected by occupancy and photo sensors. 

With this, you can test your ideas before presenting to your customer.

See http://www.streetlightingfla.com/roi.htm

Modify the 'hours of use per day' to include the effect of occ. sensors, and change the days of week to 5 if an office setting, or to 6 if a store front closed on Sundays. Change the 'Weeks of Year' for holiday schedules.

Hope this helps.


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