your 3 feet + lightset will still emits out quite a lot of LED heat. Definitely just a fraction of the MH light but closer to level of heat your T5 emits.
The good thing is that it is radiating upwards. so if you have an fan circulating the air in your hood and there are sufficient vents, it should be pretty alright.
PS : why hasn't anyone invented gel cooled padded toilet seat yet???