Our LED grow lights produce significantly more light output per watt than HPS grow lights (and more light per watt than most other LED grow lights on the market, for that matter), replacing watt for watt would provide much more light output even though you are using the same amount of electricity as with your original grow lights. As you know, plants grow better, faster, stronger and produce higher quality and larger crop yields when exposed to more light. Just think how poorly plants grow in the shade or overcast weather vs direct sunlight.