The Mildura resident believes her monthly bill was so high because she had been using the air-con when temperatures where over 40C. (Source: Supplied/Instagram)Australians have been sweltering through high temperatures this summer, with Victorian temperatures soaring to the highest levels ever recorded at 48.9C this week. Mildura resident Laureena Mierswa-Wilkinson was taken aback this week to receive a nearly $700 electricity bill for the month, covering mid-December to mid-January. Mierswa-Wilkinson believes the bill is accurate, given the couple’s high energy usage for the month and the rates they are on. Looking at her bill, some days were costing $40 when they had the air-con running.