Quick take
Annual cost depends on watts × runtime. A correctly sized unit that reaches the humidity target and cycles can cost less than an undersized unit running nearly nonstop.
Convert watts to kWh
A 600-watt unit running for 10 hours uses about 6 kWh. Multiply by the local electricity rate to estimate daily cost.
Humidity load determines runtime
Water intrusion, outdoor humidity, air leakage and space temperature determine how much moisture must be removed. Fixing drainage and air leaks can reduce dehumidifier runtime dramatically.
Efficiency ratings matter
Compare liters or pints removed per kWh when available, not just maximum extraction per day.