T4 versus T5 in undercabinet fixtures.
Every now and then I read about the slim fluorescent options for undercabinet lighting. Some units use the T4 bulbs and others use the T5 bulbs. When you compare similarly sized fixtures, the output (in lumens) and wattage tend to be similar for the T4 and T5 units.
I know that it has been asked before about which one is better, and other than choosing the option in which replacement bulbs are most easily found, I could not determine any other factors.
I noticed that the manufacturer of the Hera line of slim fluorescents available at Home Depot (Expo) claims that you must only use their replacement bulbs. I don't know if this is a warranty issue, a marketing strategy or if their bulbs are truly proprietary.
In my search for linkable fixtures, I came across the Super Sleek T4 and T5 units available from Brodax (among other similar products from other manufacturers). After a few emails with the owner of the company, I finally asked him what were the real differences between his lines of T4 and T5 slim lighting and what trade-offs or advantages one had over the other.
His response was as follows:
"The size is the main difference and the T5 series use grounded 3 prong plugs and wiring across the entire series. The T4 is probably a bit more efficient, but it's not significant enough to recommend over the T5. Go with the sizes that work for you."
Although I cannot generalize between the Brodax units and those offered by other manufacturers, it seems as if the visual differences between T4 and T5 fixtures of the same length may not be noticeable.
So, as someone previously posted, the availability of replacement bulbs may be a bigger factor than whether or not the unit has T4 or T5 bulbs.
If getting the absolute shortest (not by much) undercabinet lights are a necessity, they tend to be found in some of the T4 choices- although I have come across T5 units that were shorter than T4 counterparts. If height is a priority, you still need to compare the units by different manufacturers.
At least with the (linkable) Brodax lights, if three-prong units are required, then the T5 is the answer.
For those of you looking into slim fluorescent undercabinet options, I hope that this is useful information.