Leaving a refrigerator door open for extended periods can waste 50 to 100 kWh per year, according to Good Housekeeping. This is enough electricity for multiple cycles of a dishwasher or washing machine.
Opening a refrigerator door increases electricity usage by replacing cool air with room-temperature air, requiring the refrigerator to use electricity to cool the air again. The amount of energy used increases with the amount of time that the door is left open, with more significant usage occurring after about 30 seconds. However, unless the door is left open for extended periods, the impact on a household electric bill is nominal.