He will save power consumption from leds yes, but will also save tons of money by just upgrading to CMH.
How much money will he save per month by lowering his wattage by half ?
How many months (or years) will it take for him to compensate for the extremely high costs of these LED units, which are hit and miss from what I've seen around forums.
All questions that need to be taken into consideration imho.
If heat is such a problem just get a hood or cooltube for around 40-50 bucks and your wallet would still be thanking you.
The light spectrum on these CMH bulbs is truly unmatched anywhere.