.I find it difficult to keep the temps down in Summer,so i take a break.I did try vert,which works,but i werent getting the same yields as horizontal.
My Lecky bills are about €35 a month more than normal.but thats only using 1x600w.
Remember youve also got at least 2 fans and a ballast,at most basic setup.
If I didn't have the chimney to vent into I'd be f@&%=d for summer too, there's a Dyson brand stand alone that blows out ice cold air, you could vent through it to get rid of the heat, I'll try n get a pic for ye, Argos sells em,, goodluck swamped.