You may have noticed condensation on the inside or outside of your windows. While you don’t need to worry about the outside, excessive condensation o n the inside can damage windows, furniture, and walls inside your home. If you don’t deal with it, it can eventually harm your health too.
Here we’ll look at what condensation is, why it occurs and what you can do to prevent it.
What is Condensation?
Condensation happens when water vapour in the air turns into liquid. This liquid appears on windows or cooler surfaces.
Our homes always have water vapour in the air. It comes from our own bodies as well as things like steam from boiling water. The vapour quickly becomes invisible as it mixes with the air.
Warmer air can hold more water vapour. But there is a limit. When the air reaches that limit, we say it is ‘saturated’. Saturated air cools when it touches a colder surface. This releases extra water vapour onto that surface. At first, it looks like mist, but if there is enough of it, it becomes moisture. We call this condensation.
What Causes Condensation?
Condensation occurs on windows and doors when the inside of your home is warmer than the outside. Condensation forms in your home when these two conditions occur:
- The window glass surface is cold.
- There is a lot of water vapour in the air.
If you are getting condensation on the outside of your windows, don’t worry, this doesn’t mean your windows aren’t working. It actually means they’re doing their job. The outside pane of glass doesn’t get warmed by heat escaping through the glass, so it stays cooler than the inside, causing condensation.
Condensation on the Inside of Windows
You’ll often see condensation on the inside of your windows in winter. It happens when warm and humid air comes into contact with the cool glass. Everyday activities like showering, bathing, and cooking all contribute to the humidity in your home.
How to Stop Condensation on the Inside of Windows
As we’ve mentioned, condensation can cause damage to your home and health. If you can see it on the inside of your windows and walls , there are things you can do to stop it.
Ventilation
By improving the natural ventilation in your home, more air will flow in and out reducing the amount of water vapour in the air. Tips include:
- Extractor fans: In the bathroom, this will reduce the excessive humidity from showers and hot water. In the kitchen, it directs steam from cooking and boiling the kettle to the outside .
- Ensure window trickle vents are open: This keeps the flow of air moving in your home, improving natural ventilation.
- Keep windows open: Open at least one window in each room for a period of time each day to allow air to circulate.
- Make sure everything is working: Regularly clean kitchen and bathroom extractor fans so they’re properly functioning.
- Close bathroom and kitchen doors: It may also help to draught-proof internal doors to prevent the transfer of air with high water vapour from these rooms.
Keeping Your Home Warm
Condensation can occur in a room that is not regularly heated for cost-saving reasons, like a conservatory. In these cases, the inner glass of the window becomes almost as cold as the outside temperature. Cold air can hold less water vapour, resulting in condensation.
You’ll likely keep the windows in these rooms closed if you’re not using them. But if water vapour builds up elsewhere in the house, it will find its way into the room and won’t be able to escape.
The warmer the air in your home, the more moisture it will hold which can keep condensation levels low. In cold weather, keep your central heating on a constant background heat throughout the day. Even when you’re not home and in rooms you’re not using. If you allow your home to heat up quickly and then turn the heat off, the temperature can drop. This causes condensation as the cooler air can’t hold onto the moisture.
Reducing Excess Moisture
Make sure you also:
- Dry clothes outdoors whenever possible.
- Place radiators under windows to maintain the temperature of the inner glass.
- Use a portable dehumidifier: They extract excess moisture from the air and collect it in a tank that you empty. Dehumidifiers work well in rooms where you’re drying clothes or in a damp cellar for example.
For room-by-room advice on how to reduce condensation in your home, check out our helpful guide.
Should You Wipe Condensation Off Windows?
Yes, wipe off any condensation on your windows with a soft microfibre cloth. It’s one of the first things you should do. Not only does it protect your windows and sills, but it also helps maintain healthier indoor air quality by stopping mould from growing.
Condensation on the Outside of Windows
Condensation on the outside of your windows usually happens in the summer when it’s humid out and there’s more moisture in the air. When your window is colder than the dew outside, condensation will form. You’ll likely see it in the morning after a cool night. Condensation needs three key things to form on the outside of windows:
- High outdoor humidity
- Little or no wind
- Clear night sky
As the sun comes out and the glass begins to warm up, the condensation will evaporate.
How to Stop Condensation on the Outside of Windows
You don’t need to worry about condensation on the outside of your windows. It means they’re doing their job. If the outside of the window is cold, heat isn’t escaping from your home – your windows are working and your home is efficient.
Trimming Shrubbery Near Windows
Condensation forming on the outside of your windows isn’t a problem, but you’ll want the sun to burn off the dew as quickly as possible. Trimming shrubbery near your windows improves air circulation. It allows the condensation to evaporate as the windows warm up in the sun.
When Does Condensation Become a Problem?
If you see condensation between the glass panels of your window, it means your window seals have blown. It may look cloudy or misted and needs to be replaced. You may feel a noticeable draught and your energy bills may increase.
Excessive water can also damage your windows, lead to damp and mould, and cause problems for your health.
When Does Condensation Cause Damage to Windows?
When you have sitting water on your windows, this will eventually cause issues in your home. Specifically, limescale build-up and mould.
All uPVC windows are built to withstand water. But when seals get excessively wet and when combined with strong direct sunlight, they can dry and crack.
If you have wooden windows, the wood trim may dry and crack. Plus, the paint and varnish can peel.
Condensation damage can include:
- Limescale
- Cracked wood
- Chipped varnish
- Damage to surrounding walls
Damp and Mould
Mould caused by damp is the biggest issue caused by condensation on your windows.
Condensation on your windows can lead to damp which in turn causes mould to grow on the walls inside your home. You’ll see this as a cloud of little black dots on your walls and potentially on some soft furnishings.
Not only does it affect the look of your home, but mould also brings health risks too. According to the NHS, you’re more likely to develop respiratory problems if you have mould in your home. These include asthma, allergies or respiratory infections. Symptoms to look out for include:
- Sneezing
- Runny nose
- Red eyes
- Skin rash
How to Get Rid of Damp and Mould
You can remove mould from your walls using the following steps:
- Fill a bucket with water and mild detergent such as washing up liquid. You can also use a dedicated mould remover.
- Dip a cloth in water and wipe the mould off the wall. Don’t brush it – brushing can release mould spores into the air.
- Use a dry cloth to remove the rest of the moisture.
- Bin all the materials you used and vacuum the room to remove any spores.
Getting rid of the mould is just a stop-gap solution. If you don’t tackle the problem of moisture in your home in the first place, the mould will keep coming back. Use our tips above to tackle excess moisture inside your home.
How Double or Triple-Glazing Helps Prevent Condensation
If you heat a room, the inner glass of a double or triple glazed window will be warmer than if it had single-glazing. This makes it less likely for condensation to form when warm, moist air in the room touches the inner glass.
Although double and triple-glazing can help reduce condensation, it does not control the amount of water vapour in the air. Windows act as insulation, designed to prevent heat loss from outside your home. It’s up to you to control the moisture levels in your home.
Installing New Windows to Prevent Condensation
If you’re struggling with condensation on your windows, it might be time to replace them. If you notice moisture forming on the glass inside your double or triple glazed windows, the seals have failed on the glazing unit.
Double or triple glazed windows feature a crystalline desiccant that draws moisture out of the air gap to keep the space between the panes dry. If it isn’t dry, it’s not working properly, and you should get your windows replaced.
The current Building Regulations, called Approved Document L: Conservation of Fuel and Power, say that new or replacement windows must meet certain standards. To meet these standards, we must install energy efficient windows and doors.
To help save you money on heating, we install A-rated windows as standard. You can upgrade to A+ for even better performance against condensation. These windows capture heat from the sun and prevent heat loss, keeping your room warm.
We offer a 15-year guarantee on the majority of our sealed unit s. If your window forms condensation between the glass, we will replace it for free. Please call us or request a service visit if you are experiencing this issue.
The GGF has provided some of the information on how to prevent condensation in this article. You can download the full leaflet for free.