Is it true T5 HO ballasts suffer from heat issues?
T5HO ballasts are rated to operate at a maximum ambient temperature of 158 degrees F (70 degrees C). This can be can be reached inside a fixture when the ambient temperature surrounding the fixture is 134-140 degrees F (57-60 degrees C). A rise in ballast case temperature of 10 degrees can reduce ballast life significantly, while lower temperatures may increase ballast life. T5 HO ballasts heat issues remain as with any electronic ballast including many of the new HID products.
Most of the major ballast manufacturers currently offer 90 degree C ballasts. Although appearing to be a cure-all, there are limitations. These ballasts typically offer a five-year warranty period. When combined with a quality fixture, it could be an appropriate choice, especially for unconditioned spaces.
Aluminum is preferred over steel for a fixture’s body construction due to its ability to quickly dissipate heat. A vented housing is also crucial to maintain the optimum ballast temperature. Still, engineering is the key element for creating a controlled thermal environment that meets the performance needs of T5 HO lamps and ballasts to sustain recommended life.
With T5HO high bay fixtures becoming more recognized for their energy-saving potential, numerous companies have have begun marketing strategies. However, many of these manufacturers are simply converting existing steel product lines of T8 and T12 to T5HO by simply exchanging lamp sockets and ballasts. This has proven to be an inconsistent method with no consideration for efficiency, engineering, or the thermal issues involved.
When selecting a high quality fixture for T5-HO lamps and ballasts, make sure that it is specifically designed for for lamp performance and built to provide a stable thermal platform for the ballast. Avoid fixtures that are constructed more for appearance or lower price rather than long-term performance. Most importantly, never install a fixture in an environment that may exceed the recommended ambient temperature suggested by both fixture and ballast manufacturer.