How to Avoid Condensation on Winter Windows

We associate many experiences with winter, like dry hands, snowy weather and hot cocoa. For some people, foggy windows also make an appearance in winter. While it can be a minor annoyance, it may be a sign the humidity levels are too high in your home. If you want to avoid condensation on windows, learn about the causes, the warning signs of bigger problems and the preventive strategies you can use.

Do Your Windows Cause Condensation?

Your windows aren't responsible for condensation, but they're probably the first place you notice moisture. Think about your bathroom mirror. When you take a hot shower, the mirror fogs with condensation. Your windows are the same way.

Windows fogging up in your house doesn't make them faulty — it makes them like any other glass surface that fogs with condensate. When you see condensation on your windows, there's a good explanation. In fact, it can be a sign you have well-built windows with a strong seal. Sometimes, there can be other factors at play in your home that might require more work than wiping up the water with a rag.

What Causes Condensation?

Condensation happens when one side of your window is much warmer than the other side. The fast-moving air particles on one side touch your cold window and go through a phase change, causing the particles to become more structured. Window condensation can mean your windows are tightly sealed and preventing air leakage, which is what creates the drastic temperature difference between the inside and outside of the glass.

Exterior window condensation happens when the outside surface is lower than the dew point in the air. This situation usually occurs when the humidity levels are higher outside than inside. Summer and spring are the biggest contenders for this kind of weather, especially when you have central air or AC window units. Your air conditioning makes the air drier inside while humidity rises outside.

Condensation can even happen in the fall when the temperature drops at night. If you live in a climate where it's generally warmer and humid throughout the year, exterior window condensation might be frequent. The sun will typically dry up any moisture on your windows when this happens, but you can also apply a water repellant to keep your windows clear.

Interior window condensation happens when the humidity levels inside your home are higher than the levels outside. This event usually occurs in the winter when the air outside is dry, but you can also raise indoor humidity levels with showering, laundry and other at-home tasks. Other causes of interior window condensation include:

  • Closed shades or drapes
  • Low air circulation inside your home
  • Poor ventilation in high humidity areas like kitchens and bathrooms
  • Large collections of houseplants or woodpiles stored inside

Sometimes, window condensation happens in between the glass panels. Unlike exterior and interior condensation, this scenario is a sealing problem. Dual-pane and triple-pane windows are modern designs used to increase energy efficiency and reduce condensation. A faulty seal can make it easy for moisture to get in between the panes.

Contact your window installation professional to address condensation in between the panes.

Is Condensation on Windows Bad?

Condensation on its own isn't bad, but it can be an indicator of a bigger problem. When condensation occasionally appears in the winter, it's not something you need to take action against.

You may also notice natural discomfort at home when your humidity levels are high. Excess humidity can make it harder to sleep, cause you to sweat without much physical activity and lead to frequent dehydration.

The EPA recommends keeping humidity levels below 60% in your home. The ideal range is 30% to 50%, though it may fall lower in the winter months. Some factors can raise the humidity levels in your home, like steam radiators, plants, using the dryer and showers.

Taking preventive steps at home can help you keep healthy humidity levels, especially if your home seems prone to moisture. It helps to:

  • Keep the temperature constant.
  • Avoid drying clothing over a radiator.
  • Limit dryer usage and use a clothesline when possible.
  • Check your dryer for proper ventilation.
  • Run your extractor fan while you cook.
  • Maintain your extractor fans for strong airflow.
  • Move furniture away from the wall to prevent moisture transfer from outside.

If you use these preventive measures and still have frequent condensation issues, you can run into bigger problems. Excess humidity can cause a myriad of issues for your belongings and the people in your home. If you notice excess window condensation, it's time to investigate your home's humidity levels and find a solution to your moisture problem.

What Issues Does Humidity Cause?

Beyond excess sweating, high humidity levels can cause health issues for your family and structural problems for your house. One of the most common problems with high humidity is mold development.

Mold is a natural occurrence, and it's not possible to get rid of all the mold in your house. Excess moisture makes it an issue. If you have mold in your home and it makes contact with a damp spot, it will spread its spores, and they'll start to grow.

Sometimes, mold can develop near your HVAC system's intake. When this happens, the mold can spread quickly through your vents to other parts of your home. This spread can also occur when the insulation inside your air ducts gets wet.

Health Issues

Mold spores can produce allergens, irritants and even toxins that can cause health problems when inhaled or touched. Some people may have minimal reactions to mold spores, but those with allergies may experience hay fever symptoms like red eyes, sneezing, itchy nose and a skin rash. For people with asthma, mold can cause sudden asthma attacks.

Even in nonallergic people, mold can irritate noses, eyes, throats, skin and lungs. For people with a history of allergies, it might be hard to notice mold-related symptoms, especially if they're allergic to common substances like dust and pollen. If you're someone who rarely experiences these irritations, and you suddenly notice them, you should investigate for mold.

Mold doesn't have to spread for humidity to be harmful. Prolonged exposure to high humidity has been linked to higher rates of respiratory infections and absenteeism from school or work due to sickness. This research has also shown that relative humidity affects the rate of formaldehyde off-gassing and salts and acid formation from sulfur and nitrogen dioxide.

The Centers for Disease Control and Prevention (CDC) has found people who spend time in damp buildings are more likely to experience a range of health problems, including:

  • Respiratory symptoms in the nose, throat and lungs
  • Allergic rhinitis, also called hay fever
  • Respiratory infections
  • Worsening or development of asthma
  • Bronchitis
  • Hypersensitivity pneumonitis, a rare lung disease
  • Eczema

With the many possible health issues that come with humidity and mold, it's essential to respond to high moisture levels as soon as possible.

Structural and Property Damage

While excess humidity can be tough on the body, it can also wreak havoc on your house and the things inside. Humidity won't cause water damage on its own, but it can make leaky pipes and wet spots on your ceiling more damaging.

When there's more moisture in the air, it's harder for wet spots to evaporate. You might notice during humid summer months that the towels in your bathroom take much longer to dry, or your hair stays wet for longer after a shower. If you have a leak in your ceiling from rainwater or plumbing problems, that moisture can sit for much longer, wearing away at drywall and joists.

Fortunately, it would take some perfectly timed scenarios for this to happen. Older homes may be more at risk for plumbing issues, leaks and high humidity, so this situation isn't unheard of. But if you take care of humidity levels before disaster strikes, this sort of property damage is less likely than other types.

When mold enters the picture, structural damage happens in a different way. Mold feeds on dead or dying organic materials, like wood, fabrics, paper and some glues. You can find these materials all over your home, and when mold spreads, it eats away at your belongings. With enough time, mold can damage your wallpaper, fabrics on your furniture and even the drywall. Excess mold growth also means the environment is suited for decay fungi, mold's much more destructive cousin.

While mold tends to build up on surfaces, decay fungi work into the core of your wooden joists and support beams, causing rot. This sort of structural damage can lead to expensive repairs, and it may even make your house unsafe to live in.

How Do You Avoid Condensation and Reduce Indoor Humidity?

With all the potential problems that can start with window condensation, reducing indoor humidity is essential. Thankfully, there are several strategies and tools you can use to reduce moisture and keep everyone healthy:

1. Increase Ventilation

Ventilation is key to reducing humidity levels in any home, and it can take many forms. In the kitchen, your extractor fan improves airflow from your stove, and in your bathroom, a vent prevents condensation on the mirror and walls. Your dryer also has a vent to release moisture.

You might consider installing a whole-house ventilation system if you don't already have one. Newer homes use a range of technology to keep the space airtight, so these large-scale ventilation systems are essential for eliminating excess moisture.

2. Be Mindful of Humid Rooms

Kitchens, bathrooms and laundry areas are all prone to humidity because of the tasks you do within them. While there should be vents in these rooms to improve airflow, there are other strategies you can use to reduce humidity.

In your kitchen, tasks like boiling water, making coffee and cooking on the stovetop create humidity. Covering your boiling water can contain excess moisture and make your water heat up faster.

Limiting your shower time in the bathroom can help reduce moisture buildup in the space. While your vent fan reduces condensation on the mirror and walls, it won't work as well when you take a long, hot shower. Keep your vent running for the 15 minutes following your shower, and make sure to use a large, absorbent bath mat.

As an added humidity guard, keep the doors to your kitchen and bathroom closed during moisture-building activities. Doing so will prevent the moisture from spreading to other rooms in your home.

3. Add a Vapor Barrier to Your Crawl Space

If you have a basement or crawl space in your home, the building is more at risk for excess humidity. Building codes require insulation in these areas, which is ideal for energy efficiency. But this insulation is usually applied before the concrete is fully dry.

Concrete is highly porous and can hold onto moisture for years. With the way homes are built today, it can be challenging to avoid adopting excess moisture when you buy a house.

Installing vapor barriers can prevent moisture from entering your crawl space. These membranes sit across your soil and prevent the soil's moisture from traveling to your foundation. While these barriers can't stop water runoff from entering your crawl space, they can reduce humidity buildup.

4. Choose Houseplants With Care

If you're already living in a humid area, your plants can make the problem worse. Tropical plants like bamboo palms, monstera and ginger will release more vapor into the air than other greenery. If you still want to decorate your home with plants, try drier species like cacti, spider plants and tillandsia.

5. Regulate Levels With a Humidistat

With all your humidity management strategies in place, you can monitor your levels with a humidistat. An HVAC professional can install one for you, and you can get a reading of humidity levels in the area. If you find your levels are consistently high, you can respond with more preventive strategies.

6. Use a Dehumidifier

A dehumidifier is a valuable tool for managing humidity levels inside. You might be doing everything you can to control humidity levels, but they're still higher than the recommended range. One or more dehumidifiers can keep your levels in check along with other moisture-reducing tactics. Plus, these machines often reduce dust buildup, making your chore workload a little smaller.

Shop for Ventilation and Dehumidification Products Online

Ventilation and dehumidification are essential for your home if you see frequent window condensation. At Ingram's Water & Air, we carry reliable products at reasonable prices. Learn more about our dehumidifiers and ventilation equipment today. If you need help finding the right equipment for your home, get in touch with our team to discuss your options.

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