What Size Dehumidifier Do I Need?

What pint capacity do you actually need?

Quick Answer

For a moderately damp room of 500 square feet, you need a 30-pint dehumidifier. Very damp or wet spaces need 40–50 pints. Basements over 1,000 sq ft typically require a 50–70 pint unit. The right size runs fewer hours and costs less to operate than an undersized unit working overtime.

Data sources:EIA (US)Ofgem (UK)Last verified: July 2026
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Citation-ready summary

Summary

For a moderately damp room of 500 square feet, you need a 30-pint dehumidifier. Very damp or wet spaces need 40–50 pints. Basements over 1,000 sq ft typically require a 50–70 pint unit. The right size runs fewer hours and costs less to operate than an undersized unit working overtime.

Formula

Cost = (watts ÷ 1,000) × hours used × electricity rate per kWh.

Data used

Calculator results use user-entered wattage and usage hours, combined with residential electricity rates from the selected country or state.

Sources

Limits

These are estimates, not exact utility bills. Actual costs depend on your tariff, taxes, appliance cycling, efficiency, and how you use the appliance.