What Is The Difference Between T5 vs T8 Lighting?

Get the Most From Your Lighting: Choosing Between T5 and T8 Bulbs

As lighting evolves, new products get smaller, brighter, more efficient, and slightly more expensive. Although efficiency is key, as it provides energy savings, newer fluorescent lights are not always more cost-effective. In the following paragraphs, we will explore why T5 bulbs might not be the best option and in what application both T5 and T8 fluorescent lamps might be most beneficial. Brace yourself, this read could be electric!

What Exactly are T5 and T8 Bulbs Anyway?

For those of you unfamiliar with exactly what T5 and T8 fluorescent bulbs are, the T delineates the shape. T stands for tubular, that’s right, totally tubular man! OK in all seriousness, tubular lights can be found in many older commercial buildings, especially older schools where drop ceilings are present. Behind the foggy plastic covers of tubular lighting fixtures are usually 2 to 3 long white glass bulbs with electronic ballasts at both ends.

When switched on, electricity flows through these ballasts and into an inner compartment, called the arc tube, where it comes in contact with mercury gas. This causes the gas vapor to begin to move, resulting in ionization and the creation of short-wave, ultraviolet (UV) light. That UV light then reacts with the foggy-white phosphor coating on the inside of the fluorescent tubes, which causes it to glow. Their invention truly was a bright idea.

Standard T5 and T8 lighting are just two fluorescent bulb options that work in such a way to light our day-to-day. Measured using eighths of an inch diameter scale, the T8 fluorescent, being the older of the two versions, is slightly larger than the T5. About the circumference of a US nickel, the T8 measures 8\8 or 1 inch in diameter and comes in standard lengths of 2, 3, 4, and 5 feet. On the other hand, T5 technology is roughly the circumference of a US dime or 5/8 of an inch in diameter.

Also, available in different lengths, the T5 tubes are similarly sized; however, they are a tad shorter. The “3 footers” would be 2.83 inches, the “4 footers” would be 3.81 inches, and the “5 footers” would be 4.8 inches. So, the newer T5 bulbs are both smaller in size and length, making them more eco-friendly; however, it also makes them not interchangeable with T8. So, unfortunately, upgrading requires new fixtures. That being said, let’s explore the benefits of each and why upgrading to or installing T5 fixtures might be to your benefit.

Differences in Light Output and Watts of Power

The First thing that comes to mind when you realize that the newer T5 technology is shorter and smaller in diameter than the older T8 or T12 bulbs is whether or not there is a difference in light output or strength. We all know that as technology progresses things get smaller and still function in the way that the older ones did. Newer versions just tend to be smaller scale and often include numerous improvements. Just like the brick turned into the iPhone, The T8 turned into a slimmer, trimmer version of itself. However, just as in cellphone technology progression, the T5 is more than the one that came before.

Smaller in size but stronger in light, a standard “4 foot” (3.81 inches) T5 light bulb uses 54 watts and produces 5000 lumens; whereas, a 4-foot T8 bulb operates at a contrasting 32 watts and emits 3000 lumens. Lumens, being a measure of the quantity of light, delineates the brightness of the bulb. So, although the T5 is more petite than the T8, it takes fewer T5 fixtures to light the same size room in comparison to the T8. This is where energy efficiency comes in.

Despite that the T5 uses more wattage, 54 watts as opposed to the T8’s 32 watts, it emits a greater amount of light. Therefore, if you are using T5 fixtures to replace T8 tubes, you should plan to buy approximately 1 T5 bulb for every two T8 light bulbs you are currently using. This means you’ll be going from using 64 watts with the 2 T8 bulbs to using 54 watts with the T5 technology. Using 10% less electricity, the T5 fluorescent light bulb impresses regarding quality also. With both bulbs measuring 85 on the Color Rendering Index (CRI), the quality of the light emitted by both sources is exactly the same.

Differences in Warmth

Warmth plays a factor in three different ways with each of these bulbs. While the T5 is smaller, the higher wattage and intensity makes the bulbs give off more heat. These newer smaller versions also tend to create glare in some applications because of the focused concentration and intensity; making it necessary to use a bulb with a warmer tone phosphor layer in some instances. The T8, in contrast, does not emit much warmth and produces less glare when using a cooler-tone bulb.

Operating temperature also matters with these fluorescent fixtures. With the optimal operating temperature surrounding the bulb being 35 degrees Celsius/95 degrees Fahrenheit for the T5 and 28 degrees Celsius/82 degrees Fahrenheit for the T8, where the bulbs are being used as well as how long they are on is worth considering in taking into account the performance and terms of life expectancy. Feeling electric yet? I know I am!

Commercial Areas and Home Application

Despite that T5 lights produce the same quality of light with fewer bulbs, standard T5 lamps are not always the best light source in certain instances. With a higher lumen output emitting from a smaller area, the T5 bulbs intensity can cause glare which can make reading and using electronics an uncomfortable experience. Because of this, standard T8 lamps that emit a cooler light are better for lighting a home or office. That being said, T5 lights with a warmer color tone can help reduce glare and make using the T5 in these applications more feasible.

Indoor Growing Application

When considering which fluorescent lighting to use for growing plants, it’s a good idea to understand the positives and negatives that each brings to the table. With a higher output, the T5 is brighter which allows the plants to receive the entire light spectrum. Making them great for initiating photosynthesis. However, intense light can overstimulate plants and cause overheating. T5 bulbs should be hung at a greater height when using them for full-scale growing so that the plants don’t grow close to the bulbs which will cause overheating. The better choice for seed starting, the T5 can be hung closer to the plants when heat is needed to stimulate growth.

On the other hand, the T8 tube light emits less heat than high output T5 bulbs and can be hung closer to plants in growing applications. Although Perfect for smaller area growing, T8 fluorescent lights and older T12 lamps are less applicable for seed starting as their heat output isn’t as effective at initiating sprouting, rooting, and cloning processes.

Overview: The Main Difference

The factors that set these two bulbs apart involve levels of energy efficiency, light concentration, and intensity. Using fewer watts of power to produce the same quality of light, the T5, despite its smaller size, provides lower energy costs while producing high output, concentrated light in comparison to the T8. No matter which bulb you choose to use in your application, fluorescents are a better choice over incandescent bulbs in the long run as they produce less heat and use less energy.