I switched in February to led from 600w hps and stopped using heaters in the grow june. Saving in the summer months is amazing. Still better for me rest if year as in the loft the heat rises so as long as house isn't freezing I'm OK.
Thought this smart meter comparison might help people see usage.
To me growlights are like cars... diesel, electric, petrol.... they all get you there its just whatever you fancy.