A dehumidifier is a small refrigeration loop plus a fan. Typical portable units draw about 300–700 watts while the compressor is on. In a damp basement they can run many hours a day. That is why a “set and forget” unit can show up next to lighting on the month, even though nobody thinks of it as heat or AC.
Sizing matters. An undersized unit runs almost continuously and never quite wins. An oversized unit short-cycles. Closed doors and a reasonable humidity setpoint (not desert-dry) cut hours.
Emptying the bucket does not change watts. A pump or drain hose just removes the chore. The compressor hours still count.
Set watts and hours the compressor actually runs. A 50-pint unit in a wet cellar is not a 20-pint closet unit.
At 18.8¢ per kWh, 500 watts for 12 hours is 6 kWh — about 1.13 that day. A month of damp weather at that habit is a real line, which is why it has its own card.
Bucket vs drain
Emptying the bucket does not change watts. Hours the compressor runs do. A pump hose is convenience, not efficiency.
Related
Usage estimate only — not a utility bill, load calc, or advice.