How to Get Rid of Condensation During Winter?

Winter condensation is a common indoor humidity problem. When warm, moisture-filled indoor air comes into contact with cold windows, walls, ceilings, or other surfaces, water vapor can condense into liquid water. Persistent condensation can lead to damp surfaces, mold growth, musty odors, peeling paint, and damage to building materials.

The good news is that winter condensation can usually be reduced by controlling indoor humidity, ventilation, surface temperature, and air circulation.

What Causes Condensation During Winter?

Condensation occurs when a surface temperature falls below the dew point of the surrounding air.

For example, during winter, the indoor air may be relatively warm and humid while a window remains cold. When the warm air reaches the cold glass, it cools down. If it reaches its dew point, moisture condenses on the window.

Common sources of indoor moisture include:

Showering and bathing

Cooking

Drying clothes indoors

Breathing and perspiration

Houseplants

Wet basements and crawl spaces

Air leakage from humid outdoor air

Poor ventilation

Moisture migration from building materials

The problem is often more noticeable in bedrooms, bathrooms, kitchens, basements, and rooms with poorly insulated exterior walls.

What Is the Best Indoor Humidity Level in Winter?

The appropriate indoor RH depends on the outdoor temperature, building construction, insulation, and surface temperatures.

As a general starting point, many homes can aim for approximately 30–50% relative humidity during winter, while adjusting the level downward when very cold outdoor temperatures make window condensation persistent.

The important point is that the lower the outdoor temperature, the greater the risk of condensation at a given indoor RH.

For example, a home may be comfortable at 45% RH during mild winter weather but experience condensation on poorly insulated windows when outdoor temperatures drop significantly.

A hygrometer can help you monitor indoor RH rather than relying on how the air feels.

1. Use a Dehumidifier

One of the most direct ways to reduce winter condensation is to remove excess moisture from indoor air.

An LGR dehumidifier lowers the amount of water vapor in the air, reducing the dew point and making condensation less likely on cold surfaces.

For smaller rooms, a portable dehumidifier may be sufficient. For larger homes, basements, crawl spaces, or properties with persistent humidity problems, a whole-home dehumidifier can provide more consistent humidity control.

A properly sized dehumidifier can be particularly useful when condensation continues even though the home has adequate heating.

2. Improve Ventilation

Ventilation helps remove moisture generated by everyday activities.

Use exhaust fans when:

Taking a shower

Cooking

Running a dishwasher

Doing laundry

Bathroom and kitchen exhaust fans should discharge moisture outside the building, rather than into an attic, wall cavity, or other enclosed space.

Opening windows can also reduce indoor humidity under certain conditions, but this isn't always practical during cold weather. When outdoor air is very cold and dry, ventilation can be particularly effective because cold air generally contains less absolute moisture.

3. Keep the Home Warm

Heating the home can increase the temperature of interior surfaces, which can reduce condensation.

However, heating alone does not remove moisture.

If indoor humidity remains high, simply increasing the thermostat may not solve the problem. A better approach is to combine appropriate heating with humidity control and ventilation.

Pay particular attention to:

Exterior walls

Windows

Corners

Behind large pieces of furniture

Ceilings

Areas around doors and windows

These locations can have lower surface temperatures than the rest of the room.

4. Improve Window Insulation

Windows are often the first place homeowners notice winter condensation because glass can become significantly colder than surrounding interior surfaces.

Potential solutions include:

Double- or triple-glazed windows

Low-E glass

Properly sealed window frames

Storm windows

Insulated curtains or blinds

Replacement of damaged weatherstripping

If condensation is concentrated around one particular window, inspect that window for air leakage, poor insulation, damaged seals, or thermal bridging.

5. Improve Air Circulation

Poor air circulation can create cold spots where condensation develops.

Avoid placing large furniture directly against exterior walls when possible. Leave enough space for air to circulate.

Ceiling fans and circulation fans can also help distribute warm air more evenly throughout a room.

This is especially useful in:

Bedrooms

Basements

Closets

Rooms with exterior walls

Areas behind furniture

Air movement doesn't remove moisture by itself, but it can help reduce localized cold and humid areas.

6. Don't Dry Clothes Indoors Without Ventilation

Wet laundry can release a considerable amount of water vapor into a home.

If clothes must be dried indoors during winter, consider:

Using a properly ventilated laundry room

Running an exhaust fan

Using a dryer that vents outdoors

Operating a dehumidifier nearby

Closing the laundry area from the rest of the house

Otherwise, moisture released from wet clothes can increase indoor RH and contribute to condensation on cold windows and walls.

7. Use Kitchen and Bathroom Exhaust Fans

Bathrooms and kitchens are major sources of indoor moisture.

When showering, use the bathroom exhaust fan and keep it running for some time after the shower. When cooking, use a range hood that vents outdoors where possible.

This prevents moisture from spreading throughout the house.

8. Check Your Basement and Crawl Space

If condensation keeps returning despite normal indoor humidity, investigate hidden moisture sources.

Basements and crawl spaces can contribute moisture through:

Concrete floors

Foundation walls

Ground moisture

Plumbing leaks

Poor drainage

Wet insulation

Inadequate ventilation

A crawl space dehumidifier can help control moisture before it spreads into the living areas.

However, serious water intrusion should be addressed at the source rather than relying exclusively on a dehumidifier.

9. Prevent Condensation Behind Furniture

Large wardrobes, cabinets, and sofas placed against exterior walls can restrict airflow.

The wall behind the furniture may become colder than the surrounding room, while moisture accumulates in the stagnant air.

Try to:

Leave a gap between furniture and exterior walls

Avoid tightly packing closets

Improve air circulation

Monitor RH in problem areas

This can help reduce hidden condensation and mold growth.

10. Control Indoor Humidity With a Whole-Home Dehumidifier

If condensation occurs throughout the house, a whole-home dehumidifier may be more appropriate than several portable units.

A whole-home system can be integrated with the home's HVAC system or installed as a dedicated ducted system, depending on the equipment and building configuration.

For homes with persistent humidity problems, PREAIR offers whole-home dehumidification options, including 70 PPD, 95 PPD, and 135 PPD models.

The appropriate capacity depends on:

House size

Climate

Indoor RH

Air infiltration

Basement or crawl-space conditions

Number of occupants

Moisture-generating activities

Desired humidity setpoint

The largest available unit isn't necessarily the right choice. Proper sizing is important for effective and efficient humidity control.

Can a Dehumidifier Stop Window Condensation?

A dehumidifier can reduce window condensation when excessive indoor humidity is the underlying cause.

However, it cannot eliminate condensation caused entirely by extremely cold surfaces, inadequate insulation, or significant thermal bridging.

For example, if indoor RH is already relatively low but one poorly insulated window continues to collect water, improving the window's thermal performance may be more effective than simply increasing dehumidifier capacity.

The best solution often combines:

Humidity control + adequate heating + ventilation + insulation + air circulation.

What Should You Do if Condensation Has Already Caused Mold?

If condensation has resulted in visible mold, simply lowering humidity may not remove existing contamination.

Small areas of surface mold may sometimes be cleaned using appropriate methods, but extensive mold growth, recurring moisture, or contamination involving porous materials may require professional assessment.

More importantly, identify and correct the underlying moisture source. Otherwise, mold and condensation can return.

Winter Condensation Prevention Checklist

Use this checklist when dealing with condensation:

Measure indoor relative humidity with a hygrometer

Keep indoor RH at an appropriate winter level

Use a dehumidifier when humidity is excessive

Run bathroom exhaust fans during and after showers

Vent cooking moisture outdoors

Avoid drying large amounts of laundry indoors

Keep rooms adequately heated

Improve window insulation

Check for air leaks around windows and doors

Leave space between furniture and exterior walls

Improve air circulation

Inspect basements and crawl spaces for moisture

Fix plumbing leaks and water intrusion

Wipe persistent condensation from surfaces

Address existing mold appropriately

Final Thoughts

The most effective way to get rid of condensation during winter is to control the conditions that cause it.

Start by measuring indoor RH. If humidity is too high, use ventilation and a properly sized dehumidifier to reduce moisture. At the same time, keep the home adequately heated, improve air circulation, and address cold surfaces or inadequate insulation.

For homes with widespread humidity problems, a whole-home dehumidifier can provide centralized moisture control. For smaller problem areas, a portable or dedicated room dehumidifier may be sufficient.

Remember that condensation is often a symptom rather than the root problem. If you continue to see water on windows, walls, ceilings, or other surfaces after lowering indoor humidity, investigate insulation, thermal bridging, air leakage, plumbing, and building-envelope issues.