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Should I use T14 or T18?

As an LED lighting professional, you may be debating between using T14 or T18 fluorescent tube replacements for an upcoming retrofit project. Both T14 and T18 LED tubes can provide energy savings and reduced maintenance versus fluorescent tubes, but which is the better option for your particular application? In this comprehensive guide, we’ll compare T14 vs T18 LED tubes to help you select the right tube for the job.

Key Differences Between T14 and T18 LED Tubes

First, let’s overview the main differences between T14 and T18 LED tube lights:

  • Diameter – T14 tubes have a diameter of 14 mm while T18 tubes have a larger diameter of 18 mm.
  • Length – T14 tubes are available in lengths ranging from 22 to 65 inches. T18 tubes come in lengths from 22 to 96 inches.
  • Light Output – In general, T18 LED tubes can produce more lumens than T14, especially in longer lengths.
  • Beam Angle – T14 LED tubes commonly have a 140-150 degree beam angle. T18 tubes typically have a wider 160-180 degree beam spread.
  • Base Types – Most T14 LED tubes have medium bi-pin bases. T18 tubes use medium bi-pin bases up to 4 feet and recessed double contact (RDC) bases in longer lengths.
  • Ballast Compatibility – LED T14s work with or without a ballast. Most T18 LED tubes require a non-shunted ballast to operate.

Brightness and Light Distribution

One of the biggest considerations when choosing between T14 and T18 LED tubes is light output. Here’s how the two tube types compare in terms of brightness and light distribution:

  • Lumens – In equivalent 4 foot lengths, T18 tubes can produce up to 3,000 lumens while T14 tubes top out around 2,500 lumens. At 8 feet, T18 lamps can achieve up to 5,000 lumens vs. 4,000 lumens for T14.
  • Beam Angle – The wider 160-180 degree beam angle of T18 LED tubes produces a more diffuse, omni-directional light distribution. The slightly more focused 140-150 degree angle of T14 tubes delivers more directional lighting.
  • Luminous Efficacy – In terms of lumens per watt, performance is similar. Quality T14 and T18 LED tubes both offer 90+ lumens per watt.
  • CRI – Most T14 and T18 LED tube options provide 80+ CRI for quality, natural lighting.

For most installations, the additional light output of T18 LED tubes makes them better suited to replace conventional T12 and T8 fluorescent tubes. The more uniform, widespread distribution also helps T18 lamps work well in open and warehouse settings. However, in spaces with shelving or other obstructions, the directional illumination of T14 tubes can provide an advantage.

Length and Size Options

When replacing existing fluorescent tubes, choosing the right length LED tube is key. Here are the available size options for T14 and T18 LED replacement tubes:

  • T14 Lengths – 22″, 34″, 48″, 58″, 65″
  • T18 Lengths – 22″, 34″, 48″, 58″, 96″

As you can see, T18 LED tubes offer better length flexibility with the 96″ option to replace extra-long 8 foot fluorescent lamps. T14 LED tubes max out at just 65 inches. However, the shorter 22-65″ lengths make T14 a good choice for replacing T12 tubes in spaces with size constraints.

The smaller 14 mm diameter of T14 tubes also allows them to better fit in narrow or crowded fluorescent fixtures. However, the 18 mm diameter of T18 lamps more closely matches the size of T8 and T12 fluorescent tubes. So when space allows, T18 LED tubes can be a more natural replacement.

Ballast Compatibility

Ballast compatibility is another significant factor in choosing between T14 and T18 LED fluorescent tube replacements. There are three main options:

  • Non-Shunted Ballast – Works with LED tubes designed for use with a non-shunted (Class II) electronic ballast. Required for most T18 LED tube types.
  • Shunted Ballast – Compatible with some LED tubes designed for use with a shunted (Class I) magnetic ballast. Generally not recommended.
  • Direct Wire (Ballast-Bypass) – LED tubes connect directly to line voltage without a ballast. Easiest retrofit option but lacks controllability.

The voltage and compatibility requirements of T14 vs. T18 LED tubes differ:

  • Most T14 LED tubes work directly off line voltage or with Class I or Class II ballasts.
  • T18 LED tubes require a Class II electronic ballast for proper operation (except some direct-wire models).

So when considering ballast compatibility, T14 LED tubes offer more flexibility. In fact, direct-wire T14 LED tube options allow for simple plug-and-play retrofits without ballast bypass. Just be sure to verify the specific ballast requirements for any LED tube light before installation.

Cost Comparison

Here is a general cost comparison between equivalent T14 and T18 LED fluorescent tube replacements:

Tube Type Wattage Lumens Length Price (USD)
T14 LED 18W 2,100 4 ft. $10
T18 LED 25W 3,000 4 ft. $12

As you can see, T18 LED tubes typically cost $2-4 more per lamp given their higher light output and larger size. However, the energy savings and longevity benefits of both T14 and T18 LED tube lights make them financially advantageous over fluorescent lighting in the long run.


LED tube lights can provide dramatic lifespan improvements over fluorescent lighting. Here’s how T14 and T18 LED tubes compare in rated lifespan:

  • T14 LED tubes – 50,000+ hour lifetime (22 years at 12 hours/day)
  • T18 LED tubes – 50,000+ hour lifetime (22 years at 12 hours/day)

Overall, both T14 and T18 LED tubes offer comparable lifespans that are 2-3 times longer than fluorescent tubes. This means fewer tube replacements over the life of your lighting system.

Energy Efficiency

Switching to LED technology can also provide significant energy savings. Here’s how the efficiency of T14 and T18 LED stacks up to fluorescent tubes:

  • T14 LED tubes – Reduce energy use by 50-70% vs. T12 fluorescents
  • T18 LED tubes – Cut power consumption by 40-60% vs. T8/T12 fluorescents

Both T14 and T18 LED tube lights offer major efficiency improvements over fluorescent lighting. In fact, a quality T8 or T12-size LED tube can consume less than half the power of its fluorescent counterpart while providing the same or greater light output.

Light Quality

LED tube lights also provide performance benefits in terms of light quality:

  • High CRI – Most T14 and T18 LED tubes offer 80+ CRI for excellent color rendering.
  • Instant On – LEDs turn on instantly without delay and can be paired with controls.
  • No Flicker – LED lighting has no flicker or strobe effect.
  • No Mercury – LED contains no hazardous materials like mercury in fluorescent bulbs.
  • Cool Operation – LED tubes run significantly cooler than fluorescent lighting.

By switching from fluorescent to LED tubes, you can achieve improved light quality, controllability, and environmental sustainability. Both T14 and T18 LED replacements provide these same benefits over outdated fluorescent lighting.


So should you choose T14 or T18 LED tubes? Here are some key takeaways:

  • For maximum brightness, the higher light output potential of T18 LED tubes makes them a great choice.
  • T14 LED tubes work well for smaller spaces and offer more flexible ballast compatibility.
  • T18 LED tubes come in longer 96″ lengths for replacing extra-long fluorescent tubes.
  • Both T14 and T18 LED last 2-3 times longer than fluorescents with 50,000+ hour lifespans.
  • LED tubes cut lighting energy use by 40-70% compared to fluorescent lamps.

By evaluating your specific lighting needs, available space, ballast type, and other factors, you can determine whether T14 or T18 LED tubes are the better fit. Either option will provide dramatic improvements in efficiency, lifespan, light quality and maintenance costs compared to T12 or T8 fluorescents. Contact our lighting experts if you need any assistance selecting the perfect LED fluorescent tube replacement for your next lighting upgrade.