Glossary · Heating, cooling & ventilation

Dehumidifier

Also called: dehumidifiers · whole-house dehumidifier · basement dehumidifier · portable dehumidifier

An appliance that removes moisture from indoor air, most often used in basements and humid summers to keep humidity in a healthy range.

What it means

Portable units sit in a room, while whole-house units connect to ductwork. Set one to hold relative humidity in the recommended range. A dehumidifier treats the symptom; leaks, poor drainage or air leakage causing the moisture still need fixing.

Why it matters in an audit

Controlling basement humidity helps prevent mold and musty smells, and ENERGY STAR certified models remove moisture with less electricity.

Typical numbers

Reference values with their sources. Your auditor’s report gives the figure for your own house.

What	Value	Source
EPA target	Below 60%, ideally 30%–50%	epa.gov ↗

Sources

Learn more here

Dehumidifiers and hygrometers →

Related terms

Relative humidity (RH) How much moisture the air holds compared with the most it could hold at that temperature, shown as a percentage.
Mold Fungi that grow on damp surfaces indoors; they can damage materials and affect health, and moisture is always the root cause.
ERV (energy recovery ventilator) Like an HRV, but its core also transfers some moisture between the outgoing and incoming air, which helps manage humidity.
ENERGY STAR The government-backed blue label for products and some homes that beat minimum efficiency standards by meeting stricter criteria.
Hygrometer An inexpensive gauge, often combined with a thermometer, that shows a room's relative humidity so you can keep it in a healthy range.

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