you need to add the total wattsxhr runx 30 days then divide by a 1000, that will give you kilowatts hrs used then mutiply that by the cost of electricity in your town.
i don't have a chiller but the way i look at it is if my tank needs it it get's it. :happyfish
this is not a hobby that is cheap to start with any way
i just dont think about it :happy: that is till my wife ask