Hi I decided to check on electricity cost to run a tank and its crazy how much some people have to pay depending where they live!! To calculate the monthly cost = (x)watts x (x)hours/day x 30/31 days. Example. Heater 50watts x 24hrs x 30days = 36000 watts then it cost 0.058 for every Kwh. so it cost me 2.088 a month just for one of my heaters. This doesn't calculate all the extra fees those companies like to charge us :;smack How much do you pay??!!!