In the winter, the environment inside our homes changes- we keep doors and windows closed to keep the cold out, we run the furnace, and we may even run a humidifier to combat head colds and dry throats. These changes can cause condensation to collect on windows and other areas in your home.

Window Condensation: What is It and Where Does It Come From?

Condensation is water that was in the air and has accumulated on a surface due to temperature change. The water in the air is in a gaseous state and when it comes into contact with colder areas, it condenses and turns into a liquid. We see this same thing happen when we get a cold drink out of the cooler and water droplets collect on the can or bottle.

Condensation on your windows is often very noticeable because it takes an area of your home you are used to seeing out of and obscures the view. You may have condensation in other areas of your home, such as walls or doors, but it is less noticeable since it is on a solid surface. Because of this, we tend to worry a bit more when we see condensation on our window panes. But should we worry? It depends on your specific situation. The most important factor to consider is where the condensation is at on your window: on the outside, on the inside, or in between. Then consider: where is the condensation coming from?

Location Matters for Condensation

On Top of the Window Pane, Inside Your Home

When you see water droplets that have formed on the interior side of your windowpane, where you can touch and feel the moisture, it’s important to evaluate the situation and try to identify the source of the condensation. Condensation doesn’t appear from thin air – it generally will have a cause. Some causes for condensation inside your home could be:

• Taking a hot shower
• Cooking or boiling water
• Storing moist items near the window such as drying clothes, damp logs, or shoes
• Using a humidifier
• Having a heat source directly near the window such as an electric heater

All of these are related to the humidity levels in your home and reasons your humidity level may have risen, or that there may be a unique environment near your window causing an increased difference in temperature. Oftentimes, you can reduce the condensation in your home by reducing the humidity levels. Ventilation is usually one of the easiest ways to do this, but we’ll cover more ideas below!

Keep in mind that humidity levels in your home aren’t just affecting the appearance of condensation on your windows. It will also be reflected in other places moisture might be trapped in your home – in furniture, carpets, and even in your walls.

If your home’s humidity level doesn’t seem to be the issue, or you are seeing condensation only on specific windows with no known cause, check for leaks or drafts around the window. The seal may just need to be replaced. Lastly, If you can’t determine the source of increased humidity or moisture, and a professional can’t identify any leaks around your window, you may have a more serious problem.

On Top of the Window Pane, Outside Your Home

Seeing condensation on the exterior side of your window can be confusing. This isn’t something we are used to seeing normally in our homes, especially if you have recently purchased new windows. The good thing is, condensation on the external side of windows is a positive sign!

The reason we sometimes see condensation on the outside of a window is because of the outside conditions being more humid and/or warmer than the window pane itself. This can occur in all sorts of weather conditions. What it means is, your home is well insulated! There is zero heat escaping through your windows! Waiting for these conditions to pass and the condensation to evaporate is all you need to do.

In Between Your Window Panes

Now comes the part where you should worry. If you see condensation, fog, or moisture in between the panes of your window, you have a problem. Moisture in between window panes is an indication of a failed seal in the window. This is commonly seen in lower grade windows, or even just lower grade seals around the windows. Over time, many materials can warp and shift due to temperature changes in the environment, causing the seal to break or simply deteriorate. (learn more about what type of window materials we recommend to avoid this!) When this happens, water can get into the frame of your window and can cause it to rot or crack, especially if it is made of wood.

Another potential cause is the spacer that is held in between two panes of glass. This spacer is designed to suck up any moisture that may be in between the panes. When the seal is broken, this spacer is exposed to more moisture than it can absorb and you will begin to see condensation.

If you are seeing condensation between the panes of glass, especially if it is a sunny day, this is a definite sign that the windows need to be replaced, or at the very least, if the problem has been caught soon enough, the seal needs to be replaced.

Problems that Can Result from Condensation

Both condensation inside your home and in between your window panes can be cause for concern. One impact that tends to be an afterthought is that waiting for condensation to evaporate from your windows is actually making your home less energy efficient. Instead of using the sun’s warm rays to warm your home up on a cold winter day, it is instead being used to evaporate condensation, and you are losing that potential energy gain in your home.

More commonly, the problems that we think about being caused by moisture in the home are mold and mildew growth, water damage, and the health issues that can result from these issues. The first places you may see the effects of high humidity levels or dampness in your home are likely in areas where air circulation is low or around windows where the condensation is collecting. Visible signs could be small clusters of black dots (mold growth). Mold can damage your home and belongings very quickly as it consumes the material it grows on. This can cause the very materials your home is made to rot away – the drywall, wood, and even wallpapers. It will also affect your furniture, carpet, and even clothing and bedding.

The moisture levels can also permeate inside the walls and concealed spaces inside your home such as your attic or crawlspace and enclosed areas like the floor or roof. In these small spaces with little to no air movement, the moisture will condense and seep into the structure of your home, causing decay. The damage caused by the water and mold growth in these areas can require significant repairs, especially if gone undetected to the point of wall or structure failure. What’s worse, is as these areas absorb moisture, they change shape and size, warping with the water damage. So if your problem area was contained to just a bathroom or laundry room with poor ventilation, it can quickly spread to other areas of your home.

The other issue that can arise along with moisture problems is insect infestations. Termites especially are attracted to moisture and will quickly identify your home as their new favorite place. Once this occurs, your home will be subject to attack not only from the moisture and mold but also from termite damage. Getting damage identified quickly and repellant treatments applied should be a top priority.

Having these molds growing in your home is not just a problem for your home and belongings though. It can also cause negative impacts on your health. Some people are more susceptible to health issues from molds than others, often due to allergies or underlying health conditions, particularly in their respiratory tract. But mold can affect anyone with symptoms like coughing, eye and throat irritation, congestion, and even skin problems. Sometimes, mold can even lead to very serious infections and can even be related to other illnesses like asthma.

What to Do About Window Condensation

So what should you do about the condensation you see on your windows? The first step is to always be observant of potential issues. If you identify condensation, try to identify the cause and determine the location of the water- interior, exterior, or in between the panes. Next, resolve problems as quickly as possible. If you spot a window with condensation between the panes, have it resealed or replaced immediately and the area around the window inspected for any damage that may have already occurred. If you see condensation on the interior side of the window, identify where the condensation is coming from. If you can’t find the source, it’s time to call in a professional to diagnose the problem and recommend if you need a seal fixed, window replacement, or to diagnose the humidity levels in your home.

Additionally, if you are seeing condensation on your windows regularly, remove the condensation as often as you can, until the situation can be resolved. You should use a sponge, cloth, or other absorbent material to soak up the water. Be sure the material you choose is soaking up the water, not just pushing it around. When possible, you should also open the window for a short time to increase ventilation in the room. Any water that collects or falls on the sill or area around the window should be removed immediately as well.

Getting to the Root Problem of Condensation: Home Humidity Levels

If the condensation on the interior of your windows, and other places in your home is caused by humidity, the first step is to identify the humidity level in your home. This can be done with a tool called a hygrometer, which can be purchased for home use, or professionals will have to detect humidity levels in your home. Keep track of the humidity levels over time and see how they fluctuate. If you are seeing humidity levels at or above 60%, your home is at risk for mold growth – in fact, it’s almost certain.

Try to figure out where this humidity is coming from. Usually, it comes from daily habits that can be adapted. A few to consider are:

• Lengthy hot showers. Try to cut shower time and keep the bathroom fan running during and after showers. Also, try to space out showers if multiple people are using the bathroom. Hint: also make sure your bathroom fan is venting properly!
• Use fans or range hoods to remove moisture in the kitchen to remove excess moisture from cooking and appliances that create steam. Check that your fans are set in the proper direction for the season as well.
• Turn off your humidifier! While these are helpful for sickness and are popular with essential oil diffusers these days, it is not worth damaging your home.
• Don’t use laundry racks to dry clothes indoors. This increases the humidity level in your home immensely. While we’re on the subject of laundry, make sure your dryer vents to the outside of your home and that it is venting properly.
• Be sure your basements and crawl spaces are insulated and use dehumidifiers where necessary to remove moisture trapped in these spaces that are difficult to ventilate.
• Use dehumidifiers in all areas of your home, not just your basement. You can also use desiccant packets in your closets and drawers or near windows to soak up additional moisture.
• Don’t keep houseplants that require frequent watering. This can be a hard one to part with if you have plants that you love, but if you are experiencing humidity problems, these plants are only making it worse.
• Check your water pipes for leaks and identify what type of ventilation system your home has. Fixing any water leaks will obviously help decrease water in your home, and having an efficient, correctly installed ventilation system will improve air circulation so your home can remove moisture in the air effectively.
• Invest in new windows. If your windows are more than fifteen years old, are not double-paned, or may have warped due to temperature changes, consider investing in new windows that are higher quality and have a higher R-value. This investment can pay off big time for your home’s value, in energy savings, and in protecting your home from future moisture problems. Learn more about how to choose high-quality windows for your home, check out our blog on that topic.

Conclusion

Now that you know what to watch for, how to identify problems, and solution routes to take, you can feel prepared to tackle window condensation issues this winter. Remember that if you ever have a situation you can’t diagnose alone, we are here to help!