Which grow light is best? This is a question that is best answered once you know the space and which method you will be using. First is knowing the footprint of the light you need, if you need to spread the light to a larger area then you will need a larger reflectors. If you need the light concentrated in a smaller area you will need a smaller reflectors that will reflect the light to a smaller area. The other question is knowing if you need to exhaust the heat out of the grow room. If the answer is yes, then an air cooled hood or a cooltube is recommended. This will allow you to remove the heat out of the room, increasing the efficiency of the AC unit.