Difference Wiki

T8 Bulbs vs. T12 Bulbs: What's the Difference?

Edited by Harlon Moss || By Janet White || Published on February 4, 2024
T8 bulbs are narrower, more energy-efficient fluorescent lights, while T12 bulbs are older, wider, and less efficient.

Key Differences

T8 bulbs, measuring 1 inch in diameter, offer improved energy efficiency compared to T12 bulbs, which have a larger diameter of 1.5 inches. Both are types of fluorescent tubes used for lighting.
In terms of lighting quality, T8 bulbs typically provide a better light quality and more color options than T12 bulbs, enhancing their versatility for various applications.
From an environmental perspective, T8 bulbs are often preferred due to their lower mercury content and higher efficiency, whereas T12 bulbs, being older technology, are less eco-friendly.
Installation-wise, T8 bulbs are compatible with electronic ballasts, whereas T12 bulbs usually require magnetic ballasts, making T8 bulbs more modern and efficient.
When considering cost, T8 bulbs may have a higher initial cost than T12 bulbs, but they offer long-term savings through reduced energy consumption and longer lifespan.

Comparison Chart


1 inch
1.5 inches

Energy Efficiency


Light Quality


Ballast Type




T8 Bulbs and T12 Bulbs Definitions

T8 Bulbs

T8 bulbs are known for their long lifespan and reduced maintenance.
The warehouse switched to T8 bulbs to decrease the frequency of bulb replacements.

T12 Bulbs

T12 bulbs contain more mercury, making them less eco-friendly.
The new environmental policy mandated the removal of all T12 bulbs.

T8 Bulbs

T8 bulbs offer superior color rendering compared to older fluorescent models.
The art gallery uses T8 bulbs to accurately display the colors in paintings.

T12 Bulbs

T12 bulbs have a shorter lifespan and higher energy consumption.
To reduce energy bills, the company decided to replace all T12 bulbs.

T8 Bulbs

T8 bulbs are narrow, energy-efficient fluorescent lights.
The office upgraded its lighting to T8 bulbs to save on energy costs.

T12 Bulbs

T12 bulbs are known for their straightforward, economical installation.
The budget motel opted for T12 bulbs due to their low upfront cost.

T8 Bulbs

T8 bulbs are environmentally friendly due to lower mercury content.
The school district chose T8 bulbs for their commitment to a greener environment.

T12 Bulbs

T12 bulbs are wider, traditional fluorescent lights with less efficiency.
The old factory still uses T12 bulbs in its lighting fixtures.

T8 Bulbs

T8 bulbs are compatible with electronic ballasts for better efficiency.
During the renovation, all light fixtures were fitted with T8 bulbs and electronic ballasts.

T12 Bulbs

T12 bulbs require magnetic ballasts, an older technology.
Replacing the magnetic ballasts for T12 bulbs in the building was costly.


What is the main difference between T8 and T12 bulbs?

The main difference lies in their diameter and energy efficiency, with T8 being more efficient and narrower.

Are T12 bulbs still manufactured?

Yes, but they are being phased out in favor of more efficient lighting solutions like T8 bulbs.

Are T8 bulbs more expensive than T12 bulbs?

Initially, yes, but T8 bulbs offer long-term savings through energy efficiency.

Can T8 bulbs be used in T12 fixtures?

Yes, with appropriate modifications and ballast changes, T8 bulbs can be used in T12 fixtures.

Can T12 bulbs be easily replaced with T8 bulbs?

Replacement usually requires changing to an electronic ballast compatible with T8 bulbs.

Which bulb is more environmentally friendly, T8 or T12?

T8 bulbs are more environmentally friendly due to their higher efficiency and lower mercury content.

Is the light output of T8 and T12 bulbs the same?

No, T8 bulbs usually have a higher light output and better color rendering.

Are T12 bulbs less expensive to maintain?

No, due to their shorter lifespan and higher energy costs, T12 bulbs can be more expensive to maintain.

Do T8 bulbs offer better light quality than T12 bulbs?

Yes, T8 bulbs generally provide better light quality and color rendering.

Do T8 bulbs last longer than T12 bulbs?

Yes, T8 bulbs typically have a longer lifespan compared to T12 bulbs.

Can T8 bulbs work with magnetic ballasts?

No, T8 bulbs require electronic ballasts.

Do T8 bulbs contribute to reducing carbon footprint?

Yes, their higher efficiency and lower energy consumption contribute to a reduced carbon footprint.

Are T8 bulbs dimmable?

Yes, with compatible dimmable ballasts and controls, T8 bulbs can be dimmed.

Is it easy to find replacements for T12 bulbs?

As they are being phased out, finding T12 bulb replacements is becoming more challenging.

Are T8 bulbs suitable for all types of environments?

Yes, T8 bulbs are versatile and suitable for various environments, including offices, schools, and homes.

Do T12 bulbs require special fixtures?

They require fixtures compatible with magnetic ballasts, which are becoming less common.

Is it environmentally responsible to switch from T12 to T8 bulbs?

Yes, switching to T8 bulbs is considered environmentally responsible due to their higher efficiency and lower environmental impact.

Are T8 and T12 bulbs interchangeable without any modifications?

No, modifications such as changing the ballast are typically required.

Which bulb type is better for energy savings, T8 or T12?

T8 bulbs are better for energy savings due to their higher efficiency.

Can T12 bulbs be disposed of in regular trash?

No, due to their mercury content, they require proper disposal according to local environmental regulations.
About Author
Written by
Janet White
Janet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.
Edited by
Harlon Moss
Harlon is a seasoned quality moderator and accomplished content writer for Difference Wiki. An alumnus of the prestigious University of California, he earned his degree in Computer Science. Leveraging his academic background, Harlon brings a meticulous and informed perspective to his work, ensuring content accuracy and excellence.

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