Home Humidity and Dehumidifier Checklist

Use this checklist before buying, replacing, or continuously running a dehumidifier.

The goal is to determine:

• Which rooms are humid
• When RH rises
• Whether water is entering
• Whether ventilation or cooling helps
• What capacity is appropriate
• Whether an existing unit is working
• Whether professional repair is needed

Download: Home Humidity and Dehumidifier Checklist PDF
Printable PDF, no email address required.

Before you start

Gather:

• Hygrometer
• Thermometer, if separate
• Tape measure
• Flashlight
• Dehumidifier manual
• Utility rate
• Notebook or printable log
• Camera for documenting damage
• Model and serial information for recall checks

Do not enter:

• Flooded electrical areas
• Unsafe crawl spaces
• Areas with sewage
• Structurally damaged rooms
• Confined spaces
• Rooms with active smoke or electrical burning

Use qualified help.

Part 1: Three-day room log

Record three times each day:

• Morning
• Afternoon
• Evening

Also record after:

• Shower
• Cooking
• Laundry
• Rain
• HVAC change
• Window opening
• Dehumidifier operation

Date/time	Room	Temperature	RH	HVAC mode	Windows	Moisture activity	Condensation/odor

Use the same hygrometer location for each comparison.

Part 2: Interpret the RH

• Below 30%
• 30% to 50%
• 50% to 60%
• Above 60%
• Above 75%
• Above 90%

General interpretation:

• 30-50%: ordinary target
• Above 60%: investigate persistent moisture
• 75-90%: very damp
• 90-100%: wet or severe moisture condition

Do not respond to one short shower spike as though the entire home has failed.

Part 3: Check moisture sources

Exterior water

• Roof leak
• Gutter overflow
• Downspout near foundation
• Poor grading
• Window leak
• Foundation crack
• Groundwater seepage
• Flooding
• Crawl-space ground moisture

Plumbing and equipment

• Supply leak
• Drain leak
• Water heater leak
• Sump problem
• HVAC condensate problem
• Refrigerator or ice-maker leak
• Washing-machine hose
• Dishwasher leak
• Toilet seal
• Pipe condensation

Indoor moisture

• Showering
• Cooking
• Indoor laundry drying
• Unvented dryer
• Aquarium
• Humidifier
• Many plants
• Open windows during humid weather
• Combustion appliance
• Wet stored materials

Repair the source before relying on dehumidification.

Part 4: Ventilation and HVAC check

• Bathroom fan runs
• Bathroom fan exhausts outdoors
• Kitchen hood works
• Kitchen hood exhausts outdoors
• Dryer exhausts outdoors
• Dryer duct is intact
• AC drain is working
• AC filter is appropriate and clean
• HVAC is not short-cycling
• Exterior doors and windows close
• Outdoor air is not being added during high humidity

Record what changes RH.

Part 5: Measure the dehumidified area

Room 1:

• Length: ______ ft
• Width: ______ ft
• Area: ______ sq. ft.

Room 2:

• Length: ______ ft
• Width: ______ ft
• Area: ______ sq. ft.

Connected total:

Total area =
area 1
+
area 2
+
\cdots

Total: ______ sq. ft.

Include open connected spaces.

Do not include closed rooms the unit cannot reach.

Part 6: Classify dampness

Slightly to moderately damp

• 50-75% RH
• Occasional musty odor
• Damp feeling
• No active seepage

Very damp

• 75-90% RH
• Consistent damp odor
• Damp spots
• Moist surfaces

Wet

• 90-100% RH
• Sweating walls or floor
• Seepage
• High laundry or water load

Part 7: Portable capacity starting point

Condition	Under 2,000 sq. ft.	Over 2,000 sq. ft.
Slightly/moderately damp	20-30 pints/day	30+
Very damp	25-40 pints/day	40+
Wet	30-50 pints/day	50+

Adjust for:

• Low temperature
• High ceiling
• Open stairs
• Laundry
• Air leakage
• Several rooms
• Continuous water entry
• Whole-home need

Part 8: Product and support check

• Current pint capacity
• ENERGY STAR certification
• IEF
• Low-temperature operation
• Defrost
• Humidistat
• Bucket capacity
• Gravity drain
• Pump
• Filter access
• Noise
• Warranty
• Firmware/app requirement, if any
• Current support
• CPSC recall search completed

Do not buy by old pint labels or retail square-foot claims alone.

Part 9: Placement

• Stable level surface
• Dry floor
• Correct wall clearance
• Intake clear
• Discharge clear
• Not on deep carpet if vents can be blocked
• Not beside heat source
• Not exposed to freezing temperature
• Cord reaches wall outlet directly
• No extension cord or power strip unless expressly permitted
• Bucket accessible
• Drain route safe

Part 10: Drainage

Bucket

• Empty and clean
• Correctly seated
• Float moves correctly
• No crack
• Full-bucket switch works

Gravity drain

• Correct hose
• Downward slope
• No kink
• No clog
• Outlet not submerged
• Drain permitted
• No trip hazard

Pump

• Pump mode correct
• Pump hose secure
• Lift height within limit
• Pump tested
• Overflow plan

Part 11: Operating log

Date/time	Room RH before	Setpoint	Runtime	Water removed	RH after	Notes

Use measured RH, not bucket volume alone.

Part 12: Maintenance

• Filter checked
• Filter cleaned as instructed
• Grilles clear
• Bucket cleaned
• Hose flushed
• Drain inspected
• Coils not iced
• Cord and plug undamaged
• Outlet cool and secure
• Recall status checked

Do not open the sealed refrigeration or electrical enclosure.

Part 13: Stop and seek help

Stop using the unit for:

• Smoke
• Burning odor
• Melted plug
• Hot outlet
• Sparks
• Repeated breaker trips
• Water in electrical parts
• Damaged cabinet
• Recalled model

Seek building or remediation help for:

• Active seepage
• Floodwater
• Sewage
• Extensive mold
• Structural damage
• Wet electrical system
• Unsafe crawl space
• RH cannot be controlled after source repair
• Whole-home system needed

Final decision

• No equipment needed; RH is in range
• Improve ventilation
• Repair leak or drainage
• Use portable dehumidifier
• Replace malfunctioning dehumidifier
• Evaluate whole-home dehumidification
• Evaluate air-conditioning or HVAC issue
• Get professional moisture or mold assessment

Best target RH: ______%

Selected capacity range: ______ pints/day

Next action: ________________________________________

Frequently asked questions

How long should I log humidity?

At least three representative days, including the period when the room is usually most humid.

Should I buy from square footage alone?

No. Use space size and dampness condition.

Is bucket water the best measure?

No. Room RH and moisture conditions are more important.

Can I use this after flooding?

Use emergency and professional water-damage guidance. The checklist does not replace flood, sewage, electrical, or structural safety procedures.

Does the PDF require an email?

No. It should download directly.

Related guides

• What Humidity Should Your House Be?
• How Much Does a Dehumidifier Cost to Run?
• What Size Dehumidifier Do You Need?
• Why Is My Dehumidifier Running but Not Collecting Water?
• Dehumidifier vs. Air Conditioner: Which Do You Need?

Sources reviewed

Source notes

1. Biological Contaminants and Indoor Air QualityU.S. Environmental Protection Agency
2. Mold Course Chapter 2U.S. Environmental Protection Agency
3. DehumidifiersENERGY STAR
4. Dehumidifier Testing and CapacityENERGY STAR
5. Dehumidifier Not DrainingFrigidaire
6. RecallsU.S. Consumer Product Safety Commission

See something wrong or out of date? Report a correction.