-- Power used when the heater is running =
V²/R = (240)²/4.8= 12,000 watts. (12 KW)
(A gigantic heater ... suitable for maybe a theater, not for a home.)
-- Energy consumed in one day:
(12 KW) x (24 hours) x (25%) = 72 KwH per day
-- Energy consumed in 30 days: (72 KwH/day) x (30 days) =
2,160 KwH in 30 days
-- Cost = ($0.1 / KwH) x (2,160 KwH) = $216.00 in 30 days