Energy Efficiency Improvements with LED Lighting

Justin Stouch, Stouch Lighting

Retrofitting your current lighting with an energy efficient LED solution can save you up to 80% in annual (recurring) energy costs. The savings are so significant that you can finance the replacement of your legacy lighting with the cost savings you will realize from retrofitting your facilities with modern LED technology. When evaluating energy savings from advanced LED lights it’s important to understand energy terminologyfinancing options to ensure cash flow positive LED conversions, and to see the results from past projects where LED lighting has been successfully implemented in place of legacy solutions like fluorescent, incandescent, high pressure sodium, mercury vapor, or metal halide lighting. We’ll cover all three instances in sequence to give a comprehensive discussion of the energy efficiency advantages available with LED lighting.  

The Basics: Energy In Terms Of Electricity

The first thing you need to understand is what exactly energy is in terms of lighting. There are four basic measures you need to be aware of:

  1. Joules (J): Joules are the SISI stands for International System of Units. unit of energy defined as the amount of energy transferred when one unit of force (measured in Newtons, N) acts on an object in a particular direction over a distance of one meter, m.
  2. Watts (W): Watts are the SISI stands for International System of Units. unit of power defined as the rate of energy (measured in Joules, J) consumed or transferred with respect to time (measured in seconds, s). Watts are one of the most common ratings for lighting.
  3. Kilowatt hours (kWh): Kilowatt hours, similar to joules, describe the total amount of energy used in a given system. kWh are calculated by multiplying the rate of energy consumed from a given system in kilowatts (where 1kW = 1,000 Watts), multiplied by the number of hours the system is in operation. For example, if ten 60W lights are turned on in a given room for a single hour the energy consumption would equal 0.6kWh. For example: (10 Lights * 60W) * (1kW/1000W) * (1 Hour) = 0.6kWh.
  4. Lumens/Watt (Lm/W): Lumens/watt are the units for a measurement called luminous efficacy. A lumen is the amount of visible light emitted by a given bulb. Lumens/Watt indicates the amount of visible light the bulb emits for a given amount of energy required to generate it. It is a simple measure of energy efficiency where the higher the value the more efficient the light.

For more on jouleswattskilowatt hours, and lumens/watt read here. For more on luminous efficacy read here. Other, more advanced metrics that further define energy efficiency in lighting include useful lumens and foot candles. The basic difference between luminous efficacy (lumens/Watt) and useful lumens or foot candles (lumens/Watt·ft2) is that the former describes the total amount of light emitted by the bulb while the latter describes the amount of light emitted in the relevant target area.

For example, a fluorescent light mounted on the ceiling will emit light for 360 degrees (including useless emissions into the ceiling itself). Some of this light can be reflected and/or redirected but much of it is lost meaning the energy used to produce it (kWh is wasted. This light will have high luminous efficacy (total light emitted) but lower useful lumens and/or foot candles (total light emitted in the desired target area). An LED light, by comparison, emits light directionally (only 180 degrees) meaning there is no wasted energy directing emissions towards the ceiling instead of the room being illuminated. The light that better directs its emissions will have a higher measure for useful lumens. Because LEDs are directional they will surpass the efficiency of an equally capable omnidirectional (360 degree emitting) light of equal capability.

Advanced: Financing Your LED Lighting Retrofit With Energy Savings

  1. Amongst the most popular ways to finance an LED retrofit project are the following options:ESCOs (Energy Service Companies) and Energy Performance Contracting (EPC): ESCOs are a type of company that specializes in structuring energy efficient retrofits typically using the savings achieved through the conversion itself to finance much, if not all, of the project. Our experience working with ESCOs has been tremendously successful. For example, Stouch Lighting provided the lights in conjunction with contractor Johnson Controls for a Wilkes Barre city project from which Mayor Tom Leighton estimated savings of $549,066. ESCOs provide project design and planning, work with lighting distributors like ourselves to procure and/or manage implementation, and often provide some type of on-going reporting once the project has been commissioned. One of the major advantages of Energy Performance Contracts is that they often require zero upfront capital. They are funded through guaranteed cost savings realized over a long term future contract with an ESCO. Generally speaking, Energy Performance Contracts can last ten years or more and are a great fit for any organizations trying to improve energy related infrastructure (e.g. interior lighting, exterior lighting, etc) over the long term.
  2. In-Electric Rate Funding (IERF): The major advantage of using IERF is that it requires zero up-front capital. Funding is typically accomplished through the savings achieved via lower energy consumption over 3-5 years and an agreement with an energy supply company (utility). In-Electric Rate Funding is a popular choice for commercial facilities, large hospitals and medical organizations, industrial enterprises, and universities or corporate campuses looking to avoid upfront expenditures while still funding short-term improvements off balance sheet. It’s a good way to meet a number of goals that might include immediate energy savings, asset appreciation, decreased carbon footprint, reduced electrical load profile, and regulatory compliance. Additionally, it’s important to realize that warranty coverage is typically a normal part of an IERF project.
  3. Rebates: The third way to achieve cost savings during an LED lighting conversion is to take advantage of the many Federal State government and electric utility provider rebates available to companies making steps to improve energy efficiency. The National Conference of State Legislatures has a wonderful index of rebates for installing energy efficient lighting in your state. They advertize that “Forty-one states have incentivized the use of energy-efficient lighting through rebate, loan or tax-incentive programs.” We recommend that you work with a certified lighting professional in your region who is familiar with the various rebate options and can help guide you through the process and make sure you don’t miss any opportunities for savings. 

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