LED T8 Lamp Replacement
Linear Fluorescent Lighting: T8 Drop-In Replacement vs. T8
LED manufacturers are rushing to fill existing T-8 fluorescent lamp fixtures, (and T12s as well) with products that mimic the T-8 tube and simply replace it, usually by-passing the existing ballast. The technology in general has improved markedly, in particular for T-8 replacements, yet the most recent performance studies show it is not equivalent in performance while costs remain high.
Synopsis:
Selling points for the T-8 LED replacement are that no new fixture is required so capital costs are not stranded, no mercury is contained for customers concerned about it or constrained by local ordinances, long lamp life and reduced energy costs. LEDs also perform well under frequent on/off switching and in cold conditions. The directional nature of the LED product is touted as why much less light is needed in a given space, and much less light also means much less power is needed. High quality white light, dimmability, and reduced maintenance resulting in lower lifecycle costs are also promoted, but especially in these areas careful questions must be asked. The high first cost of the lamps ranging from $60- $120 per lamp make it nearly, if not impossible, to “payback” in energy savings over their lifetime- a term that has yet to be determined in actual use.
DOE has concluded that the mushrooming number of LED replacements for linear fluorescent lamps are not ready for prime time. CALiPER testing in 2010 indicated that the bare lamp output from LEDs was just 48% of that of the benchmark fluorescent lamp. Workplane light levels and uniformity might be inadequate given use of "drop"-in replacements (EERE, 2011). This may change at any moment. Recent work at the Lighting Research Center on a prototype LED SPE system on a two-lamp T8 4-foot troffer indicates that a similar light output could be maintained with a 28% power reduction (from 56W to 40W). The CRI (Color Rendering Index) of the LED prototype, however, was 65 so ongoing work is to maintain a high efficacy while improving the overall CRI (Lighting Research Center, 2013).
Energy Savings: 28%
Energy Savings Rating: Extensive Assessment
What's this?
| Level | Status | Description |
| 1 | Concept not validated | Claims of energy savings may not be credible due to lack of documentation or validation by unbiased experts. |
| 2 | Concept validated: | An unbiased expert has validated efficiency concepts through technical review and calculations based on engineering principles. |
| 3 | Limited assessment | An unbiased expert has measured technology characteristics and factors of energy use through one or more tests in typical applications with a clear baseline. |
| 4 | Extensive assessment | Additional testing in relevant applications and environments has increased knowledge of performance across a broad range of products, applications, and system conditions. |
| 5 | Comprehensive analysis | Results of lab and field tests have been used to develop methods for reliable prediction of performance across the range of intended applications. |
| 6 | Approved measure | Protocols for technology application are established and approved. |
Simple Payback is one tool used to estimate the cost-effectiveness of a proposed investment, such as the investment in an energy efficient technology. Simple payback indicates how many years it will take for the initial investment to "pay itself back." The basic formula for calculating a simple payback is:
Simple Payback = Incremental First Cost / Annual Savings
The Incremental Cost is determined by subtracting the Baseline First Cost from the Measure First Cost.
For New Construction, the Baseline First Cost is the cost to purchase the standard practice technology. The Measure First Cost is the cost of the alternative, more energy efficienct technology. Installation costs are not included, as it is assumed that installation costs are approximately the same for the Baseline and the Emerging Technology.
For Retrofit scenarios, the Baseline First Cost is $0, since the baseline scenario is to leave the existing equipment in place. The Emerging Technology First Cost is the Measure First Cost plus Installation Cost (the cost of the replacement technology, plus the labor cost to install it). Retrofit scenarios generally have a higher First Cost and longer Simple Paybacks than New Construction scenarios.
Simple Paybacks are called "simple" because they do not include details such as the time value of money or inflation, and often do not include operations and maintenance (O&M) costs or end-of-life disposal costs. However, they can still provide a powerful tool for a quick assessment of a proposed measure. These paybacks are rough estimates based upon best available data, and should be treated with caution. For major financial decisions, it is suggested that a full Lifecycle Cost Analysis be performed which includes the unique details of your situation.
The energy savings estimates are based upon an electric rate of $.09/kWh, and are calculated by comparing the range of estimated energy savings to the baseline energy use. For most technologies, this results in "Typical," "Fast" and "Slow" payback estimates, corresponding with the "Typical," "High" and "Low" estimates of energy savings, respectively.