Lighting specialists at Access Fixtures often encounter variations of an inquiry:
- How much will the luminaire cost to operate?
- How much money will I save by switching from x to y?
- How long will it take for this project to pay for itself?
Rather than providing a direct response, the answer takes the form of a different question:
What’s a watt worth?
The significance of a watt becomes evident when examining specific details.
For example, if you are billed $0.15 per kilowatt-hour (kWh) and operate a luminaire for 12 hours a day, seven days a week, each watt converts to a cost of $0.66.
This understanding of the value of a watt becomes even more apparent when referencing the chart below.
The operation of a 400-watt metal halide wall pack including the ballast, would consume a total of 458 watts.
This results in an annual operating cost of $302.28 when rated at $0.66 per watt.
This calculation pertains to a single 400w wall pack, highlighting the significance of understanding the value of a watt.
Determining what a watt is worth involves referencing the chart below, where the cost per kilowatt-hour (kWh) is on the left, and hours and days of operation are listed across the top.
The intersection of the rows and columns reveals the value of a watt.