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Fluorescent T8 Bulbs

Fluorescent T8 Bulbs

T8 bulbs are available as either linear fluorescent or LED tubes. T8 fluorescent tubes are commonly rated for 20,000 life hours, but range from 7,500 hours to 46,000 hours for standard T8 tubes. More energy efficient fluorescent T8 lamps can have a rated lifespan of up to 84,000 hours. T8 tubes are typically purchased by the case for large construction projects, renovation projects, and businesses taking advantage of bulk savings.

Fluorescent Tube Size and Wattage Guide

The "T" stands for the tubular shape of the bulb and the number after it is the diameter of the tube in eighths of an inch. T8 bulbs are 8 eighths of an inch, or one inch in diameter. Other common sizes are T12 bulbs which are twelve eighths of an inch or 1.5 inches diameter, and the T5 lamps which are five eighths of an inch, or .625 inches in diameter. The easiest way to know the size and wattage of your current bulb is to check the label on the end, but measuring the diameter will work if the label is illegible. The "F" signifies that the tube is a fluorescent and the number after it represents the wattage. If you're looking for a 32-Watt fluorescent tube, click the F32T8 category.

T8 Fluorescent Tube Color Temperature

Color temperature is an important factor to understand to ensure you have consistent lighting across an area. Fluorescent tubes are available in a wide range of color temperatures, so it's good to know what your application needs. The higher the Kelvin value, the bluer the bulb's light will appear. The lower the Kelvin value, the more yellow the light. For work spaces like offices, garages, and warehouses, we recommend lighting between 4000K and 5000K. Studies have shown these color temperatures can help reduce eye strain and increase productivity.

700, 800, and 900 Series Phosphors

The original fluorescent lamps were bright enough for general lighting, but the color rendering left much to be desired, with a color rendering index as low as 55 in some cases. The 700 series fluorescent light uses three different phosphors to provide red, green, and blue wavelengths, improving the color rendering index for these triphosphate tube lights. However, as technology has improved to offer more energy-efficient options, these fluorescent lamps failed to keep up with changing standards. In July 2014, all T8 700 series fluorescent lamps no longer met the new minimum allowable Lumen efficacy (lumens-per-watt) and minimum color rendering rating, so these T8 bulbs are no longer produced. Stock up while inventory is still available or upgrade to 800 and 900 series phosphors.

Most T8 lamps can be upgraded to 800 series lamps without any changes to the light fixtures. The 800 series fluorescent lamps are available with full spectrum lighting or even higher energy savings if you have an application where color rendering is less important. Like the 700 series tube light bulb, the 800 series came under review. Recent changes to energy standards mean the 800 series is also no longer being manufactured, but retailers can still sell out of existing inventory so these will still be available for years before you need to upgrade to the 900 series or LED tube lights.

How to Fix T8 Bulb Flickering - Signs of Ballast Failure

If you've had your fluorescent fixtures for a while, it may be time to service of even replace your ballast. Thankfully there are a few common signs of ballast failure you can watch out for. A failing ballast can cause your lights to dim, buzz, change color, or flicker rapidly. Check over all parts of the fixture to be safe, but when looking at the ballast, a swollen casing or burn marks are clear signs of failure.

Choosing the Right Ballast

If you know your ballast needs replacing, there are a few factors to consider when selecting a new one. The best place to start your search is knowing the type of lamp your fixture uses. Ballast spec sheets typically list which bulbs and wattages they are compatible with. If possible, match the ANSI (American National Standards Institute) code of the lamp to that of the ballast. However, ballasts are often compatible with more than one type of lamp, and vice versa. The best ballast for your T8 tubes will most likely be based on design and start method. Fluorescent ballasts have four main types of starting methods: preheat start, rapid start, instant start, and programmed start. The latter two are the newest and most popular start methods.

Fluorescent FAQ's

What is a T8 light bulb?

A T8 light bulb is a linear tube with 1 inch (2.54 cm) diameter. It can have a bi-pin or single pin base that plugs in to the sockets of a fixture. Fluorescent tube lights use low-pressure mercury-vapor gas and after a large amount of electricity is applied to the tube, it creates an electric arc of power that energizes the mercury vapor. The resulting ultraviolet (UV) frequencies stimulate the tube's inner phosphor coating, becoming visible light as it arcs across the tube and produces the familiar fluorescent glow. LED T8 light bulbs use an array of LED diodes in place of the gas and phosphor coating.

Are T8 bulbs good for growing?

Yes, T8 fluorescent lamps are preferred over T12 lamps by many growers because they produce more light more efficiently and have a longer lifespan. T8 bulbs are good for general or supplemental lighting for your indoor garden. Depending on what you're trying to grow, one lamp may not be enough. Some vegetables do best under four lamp fixtures while other plants thrive under a single lamp. Reflectors can also be used to increase the amount of light directed at the plants and you can plug the fixture into a timer to create the optimal day-night cycle for your specific crop.

What is the difference between T8 and T5?

T8 tubes are 1 inch in diameter and T5 bulbs have a 5/8 inch diameter. Unlike T8 and T12 bulbs, the two are not interchangeable as T5 bulbs require special T5 ballasts and fixtures with sockets for the smaller pin spacing on the base ends of the bulbs; a G5 base versus the larger, G13 base of T8 and T12 bulbs. Color rendering, color temperature, life hours, and Lumen output varies across both sizes; both have high output options which many growers choose for indoor gardens. For help deciding which is the right lamp setup for you, please call an account manager at 1-800-624-4488.

Do T8 LED bulbs need a ballast?

Plug-and-play T8 LED bulbs are designed to immediately replace fluorescent bulbs in a fixture with no change to the wiring, including running off the fluorescent ballast. Direct wire LED tubes require that the ballast be bypassed or removed from the fixture. After rewiring for non-shunted sockets, direct wire T8 tubes can still be used in fluorescent fixtures. Hybrid tubes offer the best of both worlds. Install directly into a fluorescent fixture until the ballast fails, then rewire the fixture for direct wire installation. This saves you from having to rewire or replace all of your fixtures at the same time. For any plug and play or hybrid installations, make sure the fluorescent ballast is listed on the ballast compatibility PDF available on each product page. For further assistance, call 1-800-624-4488 to speak with a product specialist.

Can LED lights replace fluorescent tubes?

Yes, LED lights can replace fluorescent tubes. You have three options depending on whether you want to rewire the fixture or not. Plug-and-play LED tubes are the fastest to install, running off the compatible fluorescent ballast with no rewiring to the fixture. Direct wire LED lamps take longer to install and require non-shunted sockets, but are more energy efficient. Removing the ballast also removes a point of failure, keeping the lights on longer. Hybrid tubes can be used in both plug-and-play or direct wire installations, allowing you to replace the fluorescent tubes quickly up-front, then direct wire the tubes as the ballasts fail over time.

Can T8 and T12 bulbs be interchanged?

Yes, T8 and T12 bulbs can be used interchangeably as long as the lengths, wattages, and ballasts are compatible.

How many watts are in a T8 bulb?

Both fluorescent and LED T8 bulbs come in a range of wattages depending on how much light output you desire. For fluorescent bulbs, the number after F tells you how many Watts; a F17T8 is a 17 Watt fluorescent T8 lamp. A common T8 bulb is the F32T8 which uses 32 Watts of power. The wattage for LED tube lights varies depending on light output as well. Tube lights under 1800 Lumens require fewer Watts than T8 lamps that product over 2000 Lumens.

Can you put LED bulbs in fluorescent fixtures?

Yes, there are three types of LED tube lamps that can used in fluorescent fixtures.

  • Direct wire: requires non-shunted lampholders and the ballast to be bypassed. This is the most energy efficient option and reduces maintenance over time by eliminating a failure point.
  • Plug-and-play: Requires the fluorescent ballast to operate. Check the ballast compatibility PDF on each product page prior to purchase to avoid incompatibility issues. These install within minutes, but once the ballast fails, the fixture will fail to light.
  • Hybrid: Can be used with or without the ballast. Offers a fast installation up-front, then you can change to direct wire installation once the ballast fails by bypassing the ballast and changing to non-shunted lamp holders.

Can a T8 replace a T12?

Yes, a T8 can replace a T12 bulb of the same length and wattage as long as the ballasts are compatible.

Need assistance selecting the right fluorescent tubes for your commercial application? Don't hesitate to contact us at 1-800-624-4488 to speak to our team of lighting experts.