There is a lot of speculation about weather T5 or T8 fluorescent lamps are better and why one is more preferable than the other. So in this article I will try to highlight the main differences and similarities for you to make the decision on which light to buy easier.
Efficiency / quality of light
When talking about the efficiency of both lights the T5 ones are definitely superior to T8 lamps. They have greater lumen to watt ratios which means that they output brighter and more powerful light per watt of electricity than the T8 do. The T5 lamp light also is more concentrated and focused in one area because they are smaller in diameter (there are more watts per cubic centimeter in them) so the T5 bulbs are especially good for plants when they are flowering because then they want more intense light. And the fact that the T8 bulb light isn’t that powerful means you need to put the plants closer to the bulbs to give them all the necessary light. But if we speak about the actual quality of light then although the light from T5’s is more brighter and stronger the T8 lamp light have less glare and therefore it is a bit more qualitative for humans but almoust the same for plants.
A little tip: If it is hard to understand the difference in efficiency then here is a little comparison. A 4 lamp HO T5 fixture can replace a regular 400 Watt metal halide or high-pressure sodium fixture, whereas to replace it with T8 fixture you will need a 6 lamp one.