How to Stop Condensation on Apartment Windows in Winter

 You wake up on a cold morning and your apartment windows are covered in water. Maybe the glass is foggy, droplets are running down the pane, or there is enough moisture to leave a puddle on the windowsill.

Window condensation is common during cold weather, but that does not mean you should ignore it.

The good news is that you usually do not need to replace a window or make permanent changes to a rental. The most effective approach is to reduce excess indoor humidity, improve airflow around the window, and keep moisture from sitting on the glass and frame.

Here is how to figure out what is causing the condensation and what you can do about it as a renter.

Condensation on an apartment window in winter

Why Do Apartment Windows Get Condensation in Winter?

Condensation forms when warm, moisture-containing indoor air comes into contact with a surface cold enough for the water vapor to turn into liquid.

In winter, window glass is often one of the coldest surfaces in an apartment. That makes it an obvious place for condensation to appear.

The U.S. Environmental Protection Agency (EPA) notes that condensation can be a sign of high indoor humidity and recommends controlling both moisture and airflow to help prevent it.

Everyday activities can add moisture to your apartment, including:

• showering
• cooking and boiling water
• drying laundry indoors
• using a humidifier
• washing dishes
• certain unvented appliances

The colder the window surface becomes, the easier it is for moisture in the indoor air to condense on it.

That is why a window can be dry in October but covered in droplets on a much colder January morning.

First, Check Where the Water Is

Before trying to fix the problem, look closely at where the condensation appears.

Moisture on the inside surface

If you can wipe the water away from inside your apartment, indoor humidity and the cold window surface are usually involved.

This is the type of condensation you can often reduce yourself.

Moisture between the panes

Water or fog trapped between two panes of glass is different.

You cannot simply wipe it away because the moisture is inside the window assembly. This can indicate a problem with the insulated glass seal.

As a renter, document the problem and contact your landlord or property manager rather than trying to disassemble or permanently repair the window yourself.

Water around the frame or wall

Do not automatically assume that every wet window is condensation.

Water stains, bubbling paint, wet drywall, or moisture that appears during rain can point to a leak instead.

If you are not sure where the water is coming from, take photos and report it rather than covering it up.

1. Measure Your Apartment's Humidity

Hygrometer beside a window with condensation

A small digital hygrometer can make troubleshooting much easier.

Instead of guessing that your apartment "feels humid," you can see the relative humidity level and watch how it changes after showering, cooking, drying laundry, or running a humidifier.

The EPA recommends keeping indoor relative humidity below 60% and ideally between 30% and 50% when possible.

During cold heating seasons, the appropriate level may need to be toward the lower end of that range. ENERGY STAR notes that in colder climates, roughly 30% to 40% relative humidity during heating season can help prevent window condensation.

There is no single perfect number for every apartment. Outdoor temperature, window quality, insulation, ventilation, and indoor temperature all affect when condensation begins.

Use the hygrometer as a diagnostic tool rather than treating one number as a universal rule.

2. Use the Bathroom Fan When You Shower

A hot shower can release a significant amount of moisture into a small apartment.

If your bathroom has an exhaust fan that vents outdoors, turn it on when you shower and leave it running afterward.

ENERGY STAR recommends using bathroom and kitchen fans during moisture-producing activities and continuing ventilation after you finish.

If you do not have a working bathroom fan, use whatever ventilation your apartment safely provides, such as opening a window when outdoor conditions make that practical.

And if the bathroom exhaust fan does not work, that is worth reporting to maintenance rather than simply accepting a permanently humid bathroom.

3. Use the Kitchen Exhaust Fan When Cooking

Cooking can be another major source of indoor moisture.

Boiling pasta, making soup, simmering food, or repeatedly boiling a kettle releases water vapor into the air. In a small apartment, that moisture can spread quickly into other rooms.

Use a range hood or kitchen exhaust fan if yours vents outdoors.

Covering pots when practical can also reduce the amount of steam released into the room.

If your windows always become wetter after dinner, cooking moisture may be part of the problem.

4. Be Careful When Drying Laundry Indoors

An indoor drying rack may save money and be necessary in some apartments, but the water leaving those clothes has to go somewhere.

It goes into the air.

If you regularly dry wet laundry inside and also struggle with window condensation, pay attention to your humidity readings on laundry day.

Increase ventilation when practical, avoid placing wet clothes directly beside a cold window, and consider using a dehumidifier if indoor drying repeatedly pushes humidity too high.

The same principle applies to a clothes dryer: if your apartment has one, it should be properly vented according to the appliance and building setup. EPA guidance specifically identifies moisture-generating appliances as something that should be vented outdoors where possible.

5. Turn Down the Humidifier

A humidifier can make dry winter air more comfortable, but it is possible to add too much moisture.

If you see heavy condensation while a humidifier is running, check the humidity level before assuming that your apartment needs even more moisture.

Try reducing the setting or temporarily turning the humidifier off and watch what happens to the windows.

A humidifier and a cold window can work against each other: one adds moisture while the other provides a cold surface for that moisture to condense on.

6. Improve Airflow Around the Window

Sometimes the overall humidity level is reasonable, but the air immediately around the window stays cold and stagnant.

Heavy curtains, tightly closed blinds, or furniture pushed against a window can limit air movement.

ENERGY STAR specifically recommends window treatments that allow airflow over the window surface as one way to reduce condensation risk.

Try opening curtains or blinds periodically and avoid completely trapping the window behind furniture.

A small amount of improved air circulation can help keep the inside surface warmer and reduce localized moisture buildup.

7. Ventilate When Outdoor Conditions Make Sense

Opening a window for a short period can help when the outdoor air is cold and relatively dry.

The goal is not to leave your apartment freezing all day. It is to replace some moisture-heavy indoor air with drier outdoor air when conditions allow.

EPA guidance lists increased ventilation as one way to reduce condensation and humidity.

Ventilation can be particularly useful after activities that create a lot of moisture, such as showering or cooking.

However, opening windows is not automatically helpful in every climate or weather condition. If the outdoor air itself is very humid, ventilation may not solve the problem.

8. Consider a Dehumidifier for Persistent Humidity

If ventilation and moisture control are not enough, a dehumidifier may help.

This is especially useful when your apartment consistently stays humid because of limited ventilation, indoor laundry, or other unavoidable moisture sources.

Choose a unit appropriate for the space rather than assuming the smallest model will handle an entire apartment.

Many modern dehumidifiers include a humidistat, allowing the machine to cycle on and off around a selected relative humidity level. ENERGY STAR recommends considering capacity, energy efficiency, and the conditions of the space when choosing one.

Before buying anything, however, spend a few days measuring the humidity.

If your apartment is already at a relatively low humidity level and one particular window is still soaking wet, the window itself may deserve closer attention.

9. Wipe Up Condensation Instead of Letting It Sit

Reducing future condensation is important, but deal with the water that is already there too.

Wipe wet glass and windowsills with a clean, absorbent cloth and allow the area to dry.

Do not leave towels permanently stuffed against a wet frame. Once a towel becomes damp, it can simply hold moisture against the surface.

This matters because persistent moisture can create conditions where mold grows.

The EPA recommends drying wet or damp materials quickly—ideally within 24 to 48 hours—and emphasizes that moisture control is the key to controlling indoor mold.

10. Consider Renter-Friendly Window Insulation

If a particularly cold or drafty window repeatedly develops condensation, improving its insulation may help.

Temporary interior window film is one renter-friendly option, provided your lease allows it and the product is suitable for the window and frame.

ENERGY STAR notes that properly installed plastic window film can reduce drafts and moisture buildup from condensation while adding an insulating air layer.

This approach can be especially useful with older windows.

Just remember that insulation is not a substitute for managing excessive indoor humidity. If your apartment is consistently too humid, deal with the moisture source as well.

What Not to Do About Window Condensation

A few quick fixes can hide the symptom without addressing the cause.

Do not keep increasing the heat solely to dry the window. Temperature matters, but persistent excess moisture still needs to be addressed.

Do not run a humidifier blindly. Check the actual relative humidity first.

Do not ignore standing water. Dry the glass and frame rather than allowing water to remain there day after day.

Do not permanently seal or modify a rental window without permission. A failed seal, damaged frame, leak, or installation problem belongs in a maintenance request.

And do not assume visible moisture is always normal condensation. A building leak needs a different solution.

When Should You Contact Your Landlord?

Occasional light condensation on a very cold morning does not necessarily mean the window is defective.

But some situations deserve a maintenance request.

Contact your landlord or property manager if you notice water trapped between panes, obvious gaps or damage around the frame, water entering during rain, persistent wet drywall, peeling or bubbling paint, recurring mold, or condensation so severe that water repeatedly pools around the window despite reasonable humidity control.

Take photos before cleaning the area, especially if the problem keeps returning.

It can also help to record your indoor humidity readings. Saying, "This window is wet every morning even when the room is around 35–40% RH" gives maintenance more useful information than simply saying the room feels damp.

Can Window Condensation Cause Mold?

Condensation itself is water, not mold.

The concern is what happens when surfaces stay damp.

Mold can grow when sufficient moisture remains available, which is why the EPA emphasizes fixing moisture problems and drying wet areas promptly.

Pay particular attention to:

• window seals
• painted or wooden sills
• drywall around the frame
• curtains touching wet glass
• carpet below the window

If you repeatedly wipe away water but never reduce the underlying moisture, the problem is likely to return.

A Simple Morning Routine for Wet Windows

If you regularly wake up to condensation, keep the routine simple.

First, wipe the glass and sill dry. Then check your hygrometer.

Think about what added moisture the previous evening: a shower, cooking, laundry, or a humidifier.

Ventilate if outdoor conditions are suitable, use your exhaust fans, and give the window some airflow by opening curtains or blinds.

After a few days, you may start seeing a pattern.

That pattern is far more useful than trying random fixes one at a time.

Frequently Asked Questions

Is condensation on apartment windows normal in winter?

Some condensation can occur when warm indoor air meets very cold window glass. However, heavy or persistent condensation should not simply be ignored, especially if water pools on the frame or nearby surfaces.

What humidity should my apartment be in winter?

EPA guidance recommends keeping indoor relative humidity below 60% and ideally between 30% and 50%. ENERGY STAR notes that colder climates may require approximately 30–40% RH during the heating season to help prevent window condensation.

Will a dehumidifier stop window condensation?

It can help when excess indoor humidity is a major cause. But condensation can also be affected by window temperature, insulation, outdoor conditions, and airflow, so a dehumidifier is not guaranteed to solve every window problem.

Should I open my windows in winter to stop condensation?

Short-term ventilation can help when outdoor air is cold and dry because it allows humid indoor air to escape. You do not necessarily need to leave windows open for long periods.

Should I tell my landlord about condensation?

Report it if moisture is trapped between panes, you suspect a leak, the window or frame appears damaged, mold repeatedly returns, or water continues to accumulate despite reasonable humidity and ventilation measures.

Final Thoughts

Stopping apartment window condensation is usually less about one magic product and more about controlling moisture.

Start by measuring indoor humidity. Use bathroom and kitchen ventilation, watch moisture from laundry and humidifiers, improve airflow around cold windows, and dry condensation instead of letting it sit.

If one window remains unusually wet while the rest of the apartment seems normal, document it. At that point, the problem may require your landlord or maintenance team rather than another renter DIY fix.

Keeping the glass clear is useful, but the bigger goal is simple: keep excess moisture from lingering long enough to damage the apartment or create conditions for mold.