Calculating Your Lighting Only Energy Saving In An LED Retrofit

by | Nov 3, 2020 | 0 comments |

This is the first article in our latest series: Calculating Your Savings and ROI on any Lighting Project. Please also see: Calculating your HVAC Energy Savings, Calculating your Maintenance Savings Part 1 & Part 2, Calculating your ROI.
Before you can start calculating your lighting only energy savings in an LED retrofit, you need to know what it’s referring to. The simple explanation is, it’s the money companies save when they switch to energy-efficient lighting products. Using the savings for lighting only is an ideal place to start your calculations since it reflects the majority of the savings you realize on most lighting retrofit projects. You are using math and science in your calculations so you know you can trust this method.

Step-by-Step Energy Savings Calculation for Lighting Only

For the sample lighting, only energy savings calculation we’re presuming that 90 watt halogen lamps were replaced with 14 watt LED ones. From there, you’ll follow these 5 steps.

Step 1: Gather the Product Information

You’ll need the following information on your products to accurately calculate your energy savings.

  • Old product wattage: In our example, it’s 90 watts
  • New product wattage: For this LED calculation it’s 14 watts
  • Running time: How many hours are the lights on?
  • Hours per day: 12 hours
  • Days per year: 250
  • Electricity rate: Your previous energy bill will have the electricity rate listed. Nationally, utility rates average between $0.10.kWh – 0.14/kWh. For our calculation, we’ll use a rate 0f $0.12/kWh.

Step 2: Calculate the Energy Savings for Each Installed Lamp

Using your LED savings calculator, you’ll input the information collected in step 1. For example,

  • The wattage of your old lights was 90 watts.
  • You’ll subtract it from the wattage of the new lamps, 14 watts.
  • The resulting number is 76 watts, and this is what you are saving in wattage for each new lamp.

The equation is 90 watts – 14 watts = 76 watts per lamp.

Step 3: Calculate Total Hours Lights are On

  • Hours on per day: 12 hours
  • Number of operating days: 250 days
  • It equals 3,000 hours per year the lights are turned on.

The equation is 12 hours x 250 days = 3,000 hours per year.


Step 4: Calculating Energy Savings per Lamp in Kilowatt-hours (kWh)

  • You know that you’re saving 76 kWh per lamp.
  • It is multiplied by 3,000 operating hours per year.
  • Divided by 1,000 – to convert the total into kWh.
  • Equals: 228 kWh saved per year.

The equation is 76 x 3,000 ÷ 1,000 = 228 kWh savings per year.

Step 5: Calculate the Yearly Savings

  • Energy savings per lamp: 228 kWh
  • Times electricity rate: $0.12/kWh
  • Equals: $27.36 in energy savings for each lamp per year.

The equation is 228 x 0.12 = $27.36
Using your LED ROI calculator you will multiple the savings of $27.36 by the number of energy-efficient lamps you have installed. The resulting answer gives you the total lighting only savings for the year.

Know Your Lighting Only Savings

It is surprisingly easy to calculate your lighting only energy savings and the resulting answer from the final equation may surprise you. Chances are your retrofit lighting project is not only paying for itself, it is also giving you a financial return. To speak with an Action Services Group lighting specialist, call Action Services group today at 610-558-9773, email [email protected] or schedule a call.


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