Should I Upgrade to Fluorescent or Wait for LEDs to Get Cheaper?
LED lighting is awesome, and it’s getting better and better with each passing month. In fact, if you’re familiar with Haitz’s law, you know it states that LED will improve in efficiency and go down in cost over time. The law predicts that eventually, solid-state Lighting will become much more efficient, and affordable, than it is today.
That leaves some building owners with a quandary. If energy-efficient lighting is going to be even more energy-efficient tomorrow than it is today, is it better to wait for those advances to upgrade your lighting, or upgrade your lighting using the technology available today?
Let’s answer that question using the hypothetical example of a warehouse with 1,000 400-watt metal halide fixtures, since nice round numbers like 1,000 make the math easy.
At an average cost of 9 cents per kilowatt, a system of 1,000 400-Watt metal halide fixtures costs $41.22 per hour to run. (a 400-Watt metal halide fixture actually consumes about 458 Watts). If the fixtures are on an average of 730 hours every month (730 x $41.22), it ends up costing $30,090.60 every month to light the warehouse.
So - let’s compare two options for a retrofit of our hypothetical warehouse. One is an energy- efficient four-lamp T5-HO fluorescent fixture, the other is the new [P2] QHC LED high bay. When replacing a 400-watt metal halide, they both cut energy consumption significantly.
Of course, cutting energy consumption and costs at the fixture aren’t the only reasons to upgrade your lighting. An energy-efficient lighting retrofit can also improve your overall lighting quality by providing the right amount of light in the places it’s needed. Plus, to save even more, you can add automated lighting controls to your retrofit.
Since current-generation fluorescent and LED lighting work well with occupancy and daylight sensors, we’ll assume that our retrofit will let us cut the estimated hours of operation in our warehouse to a reasonable 300 hours per month. HID systems, in contrast, don’t work well with sensors due to their longer restrike times (the amount of time it takes the fixture to reach full brightness after being turned on).
The accompanying table shows the what we get when we run the numbers. As you can see, over a five-year period, the potential savings from a retrofit can be huge. Would you be willing to wait on the promise of future advances in LED lighting, and give up more than $1 million in savings? We certainly wouldn’t.
What this chart doesn’t tell you is whether fluorescent or LED will be a better option for your retrofit. Right now, your initial costs will be significantly lower with fluorescent, but there are other factors that could make either technology the best solution for a given application.
What this chart does show is that if you’re sitting around waiting for new technology to show up before taking on a lighting retrofit, you’re wasting quite a bit of money.