Dehumidifier Run Cost Calculator
Calculate monthly dehumidifier electricity cost from wattage, hours per day, and your kWh rate.
See annual running cost too, not just sizing.
Most people pick a dehumidifier by pints-per-day capacity and never look at how much it costs to run.
A 50-pint Energy Star unit pulls about 500 watts when the compressor is on.
A non-Energy Star 50-pint pulls 700-800 watts for the same job.
Across a humid summer in a damp basement, that gap is real money.
The math is one line:
monthly_cost = (watts × hours_per_day × 30) / 1000 × price_per_kWh
A 500 W dehumidifier running 12 hours a day at 16 cents per kWh costs $28.80 per month.
The same unit running 24 hours in a wet basement during a rainy week costs $57.60 — almost double.
Dehumidifiers do not run continuously even when set to “always on."
They cycle: compressor on for 20-30 minutes to pull moisture, off for 10-20 minutes while the humidistat re-evaluates.
The hours-per-day input is compressor-on time, not how long the unit is plugged in.
A reasonable estimate for a moderately humid space is 8-12 hours per day; very damp basements or summer crawl spaces can push 18-22 hours.
Whole-house dehumidifiers (Aprilaire, Santa Fe, Ultra-Aire) draw 600-900 watts but run less frequently because they share air with the HVAC system and their dryer output gets distributed instead of recycled in one room.
Per pint removed, they use about 30% less electricity than a portable.
The downside is the install cost: $1,800-3,500 versus $250 for a portable.
A few practical points.
Bucket-emptying portables and pump-drained portables draw the same wattage; the pump itself adds maybe 2-3 watts when active.
Cold rooms reduce dehumidifier efficiency sharply — a unit rated for 50 pints at 80°F may pull only 20 pints at 60°F, and runs longer to do less work.
If your basement is consistently below 65°F, a desiccant dehumidifier (which uses a different mechanism) outperforms a compressor unit despite higher rated wattage.