<img height="1" width="1" style="display:none" src="https://www.facebook.com/tr?id=448100748896598&amp;ev=PageView&amp;noscript=1">
  • Corporate
  • Lighting
  • Electrical
  • Studio
Login/Signup
Regency Lighting logo
  • Shop Products
    • Light Bulbs
    • Ballasts & Drivers
    • Batteries
    • Electrical
    • Fixtures
    • Specialty
    • Business Account Signup
  • Services
    • Problems We Solve
    • Architectural Lighting Design
    • Lighting Supply
    • Electrical Supply
    • Construction Services
    • Lighting Retrofits
    • Disinfectant Lighting
    • Product Lines
    • Client Success Stories
  • Resources
    • Lighting Blog
    • Total Cost of Lighting
    • Energy Savings Calculator
    • Lighting Glossary
    • Title 24
      • Title 24 FAQ & Glossary
      • Does Title 24 Apply to Me?
  • About Us
    • Culture
    • Values
    • Causes
    • History
    • Team Success Stories
    • Leadership
      • Ron Regenstreif
      • Mike Goldstone
      • Scott Anderson
      • Judah Regenstreif
      • Ron Pilner
      • Hoon Kim
    • Careers
    • Regency Lighting News
    • Event and Social Photos
    • Regency Branding
  • Contact Us
    • Credit Application
    • Apply for Tax Exemption
    • Contractor Network
    • Office Locations
  • Store Login

Start typing and press Enter to search

bg.jpg

Lighting Insights Blog

Lighting Insights from Regency Lighting Regency Lighting Logo

< Back to blog

How to calculate energy savings for lighting only: A step-by-step guide

Posted by Chris Radosta on Oct 20, 2015 10:30:00 AM
Find me on:
LinkedIn
print
  • Tweet

support image for How to calculate energy savings for lighting only: A step-by-step guide article

This is the first in our series of blog posts meant to take the mystery out of savings and payback calculations for lighting. Regardless of your role within a company, from design to energy to construction to maintenance, a lighting project will likely come across your desk at some point. We are here to arm you with some simple tools to make sense of the numbers. 

Start with the basics

Lighting-only energy savings is essentially the money you save from the simple wattage reduction when switching to more efficient lighting products. A “lighting-only” number is a good place to start because it is the most conservative savings calculation in a lighting retrofit and it represents the bulk of the savings you will capture on most retrofit projects. Further, it is to be trusted. It's plain science and math. 

For our example, we will assume that you are replacing a 90 watt PAR 38 bulb with a 14 watt LED PAR 38. Let’s get started!

Step 1: Gather your facts

You will need to pull together the following items before we dive into the calculations.

  • Old product wattage: In our example this is 90 watts.

  • New product wattage: In our example this is 14 watts.

  • Running time: How much time out of the day is the product lit?

    • How many hours per day is the product lit? We will use 12 hours.
    • How many days per year is the product lit? We will say 360 days (holidays are nice, right?).
  • Electricity rate: This can be tricky depending on the utility rate you are paying, but a reasonable national average is $0.10/kWh to $0.14/kWh. For our example, we will use $0.12/kWh. 

Step 2: Calculate energy savings per bulb

Once you have all of your information together, the best place to start is to calculate the energy saved for each bulb replaced. 


   Old Product Wattage
– New Product Wattage

= Energy Savings per Bulb

Our Example:
   90 Watts (Old Halogen)
– 14 Watts (New LED)

= 76 Watts Saved per Bulb

Step 3: Calculate annual running time

The amount of time that a product is lit has a significant impact of savings and payback.

In our example, we assumed the lighting is on 12 hours per day and 360 days per year. 


   Daily Run Time
x Annual Days of Operation

= Total Annual Run Time

Our Example:
   12 Hours per Day
x 360 Days per Year

= 4,320 Hours

Step 4: Calculate total annual energy savings

Total energy savings is figured out in total kilowatt-hours, or kWh – the measurement your utility company uses to track your energy consumption. We will divide by 1,000 to convert watts saved to kilowatts saved so the energy calculation is easier.


   Energy Savings per Bulb
x Total Annual Run Time
÷ 1,000

= Total Energy Savings

Our Example:
   76 Watts Saved per Bulb
x 4,320 Hours per Year
÷ 1,000

= 328 kWh Saved

Step 5: Calculate annual dollar savings

Okay, so we know we’re saving a boatload of electricity, but we need to see how it translates to real dollars. 

 

   Total Energy Savings
x Electricity Rate

= Total Dollar Savings (from Lighting Only)

Our Example:
   328 kWh Saved
x $0.12/kWh

= $39.36 Saved per Bulb per Year

Now that you’re a pro on figuring out how much you can save per bulb, you can scale to any size product and get a “gut-check” on the savings estimates that find their way to your desk.

 Ultim

Additional Resources:

  • How to Calculate Return on Investment (ROI) and Payback for Your Lighting Project
  • How to Calculate Labor Savings from Long-Life Lighting
  • How to Calculate Material Savings from Long-Life Lighting
  • How to Calculate HVAC Energy Savings from Lighting
  • The Plain Truth Behind Lighting Retrofit Savings

Topics: LED, Savings, Payback, & ROI, Energy Efficiency, Energy Savings, Wattage

Related posts

4 reasons lighting causes developers' schedules to fall behind on construction projects
4 reasons lighting causes developers' schedules to fall behind on construction projects
Trends in pricing and quality in LED lighting
Trends in pricing and quality in LED lighting
California's light bulb ban
California's light bulb ban

Have a comment?

Sign up for a Regency Lighting Business Account

Shop Regency Lighting

Recent articles

View all posts >
 

Articles by topic

  • LED (79)
  • Energy Efficiency (43)
  • COVID-19 (42)
  • Lighting Retrofits (36)
  • Commercial Office (30)
  • Fluorescent Lighting (29)
  • Retail (28)
  • Energy Savings (26)
  • Lighting Design (25)
  • Savings, Payback, & ROI (24)
  • Germicidal UVC (23)
  • Cleaning & Disinfection (22)
  • Parking (22)
  • Restaurants (22)
  • Lighting 101 (21)
  • Lighting Maintenance (21)
  • Hotels (20)
  • Hospitality (19)
  • Inside the Industry (18)
  • Lighting Technology (18)
  • Product Comparison (18)
  • Lighting Rebates (17)
  • Multifamily (17)
  • Project Management (16)
  • Education (13)
  • Healthcare (13)
  • Energy Code & Restrictions (12)
  • FAQs (11)
  • Incandescent Lighting (11)
  • Indoor Air Quality (11)
  • New Construction (11)
  • HID Lighting (10)
  • Lighting Tidbits (10)
  • Inside Regency (9)
  • Ballasts (8)
  • Movie Theaters (8)
  • Color Temperature (7)
  • Light Color & Quality (7)
  • California Energy Code (6)
  • Industrial & Warehouse (6)
  • Title 24 (6)
  • LED Dimming (5)
  • T12 (5)
  • Building Inspections (4)
  • CFLs (4)
  • LED Lifespan (4)
  • Lighting Controls (4)
  • Lighting as a Service (4)
  • Wattage (4)
  • Energy Star (3)
  • Part Numbers (3)
  • Warranty (3)
  • Charity (2)
  • DLC (2)
  • Hallways (2)
  • Color Quality (1)
  • ETL (1)
  • Halogen Lighting (1)
see all
HQ
9261 Jordan Avenue
Chatsworth, CA 91311
Phone: +1-800-284-2024
Send us a message.
Find a location.

National Lighting Distributor since 1983

RSS Lighting Insights
  • 4 reasons lighting causes developers' schedules to fall behind on construction projects Aug 1, 2022
  • What is DLC v5.1 and how does it impact my lighting purchase? Jul 26, 2022
  • Trends in pricing and quality in LED lighting Jul 19, 2022
  • California's light bulb ban Jul 13, 2022
  • Is there an incandescent light bulb ban? Jul 11, 2022
  • A state by state look at light bulb bans [Interactive map] Jul 6, 2022

Looking for products?

View Product Lines
Shop our Store
© Regency Lighting, All Rights Reserved.
  • RL Studio
  • Shop Lighting
  • Shop Electrical
  • Privacy Policy
  • Site Map