Everybody keeps telling me it is cheap to run an air purifier 24 hours a day. How cheap would it be if I run it on max speed?
It's easy to calculate an air purifier energy cost. First you calculate the total wattage consumption per day e.g. 70 watts X 12 hours = 840 W. Then you convert watts to electricity measurement kilowatts e.g. 840 watts/ 1000 = 0.840 kWh. Continue calculating the monthly/ yearly usage by multiplying accordingly. E.g. 0.840 kWh x 30 = 25.2 kWh per month. Finally, use your local electricity rates, multiply the figure, and voilà, there is your answer. E.g. 25.2 kWh x 0.15 = $3.78 per month. Using that as a baseline, on average of 12 hours daily operation, you should be paying between $3-8 dollars monthly. Hardly causing any dent on your electricity bill.
Some air purifiers are more energy-efficient than others while some have Eco-mode that will turn off the motor fan when not in use. Look for models that are Energy-Star Rated is a good way to start, features like Auto/ Sleep mode does keep usage under control. One more thing, electricity cost for residential varies from states to states. Visit U.S. Energy Information Administration (eia) for the latest cost table.
Again I repeat, air purifier does not cost a lot to run because it consumes very little electricity. On average, a mid-range model with 12 hours of daily use would only cost you between $3-8 dollars.