T8 or T5-HO: Which should I use?
Numerous discussions surround the decision to use T8 or T5-HO lamps
when replacing an HID fixture. As a manufacturer that utilizes both lamp types in our fixture designs, we would like to offer some important points you may want to consider. If you ask the right questions, you should get the answers that will help lead you to the right decision.
For clarification, we are addressing the use of T8 and T5-HO lamps in industrial applications, specifically high and low-bay lighting. Indirect lighting for office space is a separate topic. We feel T8 lamps provide a better quality of light with less glare in areas where the fixture height is lower than 20 feet. The T5-HO lamp delivers a brighter light source within a smaller diameter allowing us to design the reflector with better optic precision. This provides better quality light output and higher fixture efficiency.
As a general rule of thumb, a T5-HO fixture should be used in applications above 20 feet and T8 fixtures below 20 feet. There is a gap between 18 and 25-foot heights where either T8 or T5-HO fixtures can be used successfully. This is where you really need to pay attention to what you’re asking for and what you may get.