You won't even cause a blip with that setup...maybe like $10 -$15 a month. My 400w HPS with a 6" vortex fan run 18/6 while a circulating fan and a dayton exhaust fan run 24/7 - my bill is about $60 higher with that setup.
doco Reviewed by doco on . electricity bill HELP how much does a fan and a 150w hps and a couple of cfls add to the electricity bill. and this is an unusual usage of electricity so wont the feds suspect something? big time growers have gotten busted this way. Rating: 5