To prevent condensation on aluminium window frames, cut indoor humidity and keep the frames warm: ventilate daily, use extractor fans and a dehumidifier, avoid drying clothes indoors and wipe frames dry. Long term, thermally broken frames with double or triple glazing stay warmer and attract far less condensation than older aluminium windows. Depending on the climate you live in, or the season, temperature changes can result in foggy windows.
People who live in the UK especially have to deal with fogged-up windows due to the change in weather.
Modern aluminium windows are light years ahead as they are designed to resist the build-up of fog. Despite this, there are measures you can take to further help avoid this from happening.
Let's dive into this article to discuss how to prevent condensation on aluminium frames.
How Does Condensation Form on Aluminium Windows?
Condensation forms when warm, moist indoor air touches a surface colder than its dew point, usually the glass or frame, and the water vapour turns into droplets. It is worst in winter, in kitchens, bathrooms and bedrooms, and on older frames that conduct the cold.
Two key factors for condensation to form are hot air and colder surfaces.
Condensation forms when excess moisture is in the air, which then shows up as condensation on the glass. Usually, the humid air rests on a cold surface where the water vapour collects.
During winter, cold window frames are affected by the warm air inside the room.
This can occur naturally on the outside of your window, or it can be as a result of the change in the air temperature in the home. If it is too hot on the inside and there is no ventilation, condensation will form.
The colder the surface area, the foggier your windows will be.
Are Aluminium Window Frames Prone to Condensation?
Older aluminium frames without a thermal break are prone to condensation because aluminium conducts heat quickly, so the inner frame gets cold. Modern thermally broken frames have an insulating barrier between the inner and outer sections, keeping the inside face warmer and greatly reducing condensation.
Every window has a U-value. The U-value refers to the insulating properties that these window frames have. If the U-value is higher, the aluminium windows cannot insulate properly, and condensation occurs.
The thermal break (or a lack thereof) between the exterior and interior of the aluminium window frame can result in a temperature drop. This causes a condensation problem.
Older windows become cold easily as there is no or little insulating barrier to reduce condensation.
However, modern thermally broken aluminium windows are far less prone to condensation, as these frames are insulated to keep heat in.
What Problems Does Condensation Cause?
Regular condensation leads to black mould on seals, sills and walls, peeling paint, damp plaster, damaged window seals and poorer indoor air quality, which can aggravate asthma and allergies. It is also a sign that humidity is too high elsewhere in the home. If mould has already appeared, follow our guide to cleaning mould off aluminium window frames.
Window sweating is when condensation builds up on the window. If you have an air leak, the window sweat can cause mould in the window frame and even in the walls around your windows.
This could lead to serious health problems such as asthma and other allergies that can become chronic illnesses over time. The negative effects caused by window sweating can also damage the window seals. This allows heat to escape and condensation to become a natural occurrence.
Aluminium window frames' condensation can be curbed by using energy-efficient windows. It is important to also check your existing windows for any cracks or leaks.
What Happens When Condensation Gets Between the Glass Panes?
Condensation between the panes means the double-glazed unit's seal has failed and moist air has got into the cavity. It cannot be wiped away or cured by ventilation; the sealed glass unit needs replacing, which can usually be done without changing the frame.
Since glass is one of the coldest materials in your home, it attracts warm air. The temperature, combined with the humidity level, leads to condensation. The point at which condensation develops is known as the dew point.
If a sealed unit has failed, our guide to changing the glass in aluminium windows explains how to replace it without changing the frame.
If you notice the moisture inside the windows, it indicates that the surface temperature is cooler than usual, and you might need to replace your window panes.
How Do You Stop Condensation on Aluminium Windows?
Reduce moisture and improve airflow: open windows or trickle vents daily, use extractor fans while cooking and showering, run a dehumidifier, dry clothes in a vented or condenser dryer, keep the heating at a steady temperature and wipe away droplets each morning. Replacing old frames with thermally broken, double-glazed windows is the lasting fix.
To eliminate condensation permanently, you may need to upgrade old aluminium windows to thermally broken, double-glazed frames. Our guide to how much aluminium windows cost explains what to budget.
Here are some other tips on how to prevent condensation on aluminium window frames:
Does a Window Vacuum Help With Condensation?
A window vacuum is more straightforward than a towel to wipe up all the moisture off the windows. Since window vacuums are usually used to remove soap and water, they can also help remove condensation.
The water vapour will collect within the vacuum. This makes it easier as you can control where the moisture collects.
This is effective in wiping up and clearing the windows of condensation. However, it doesn't solve the problem long-term if you need new windows.
Does a Dehumidifier Stop Condensation?
A dehumidifier is ideal for preventing condensation on aluminium windows. Sucking up all the moisture in the air makes it harder for condensation to form, even if it falls on colder surfaces.
They also help in eliminating mould, which is certainly not something you want growing on your windows!
Desiccant dehumidifiers also give off a little warmth, which can help in cold rooms.
How Do You Stop Moisture at the Source?
Certain areas within the home, such as the bathroom and kitchen, produce moisture that leads to fogged-up windows.
To prevent condensation from building up throughout the house, have the door closed when taking a shower or bath. Immediately when you are finished, you can open a window to help extract the moisture from the room.
Installing bathroom vents is another way to prevent condensation.
Use your kitchen extractor fan whenever you cook, and leave it running for 10 to 15 minutes afterwards to clear the moist air.
What Humidity Level Should You Keep at Home?
Aim for a relative humidity of around 40% to 60%. A cheap digital hygrometer shows when levels are rising, so you can ventilate or run a dehumidifier before condensation forms.
Using a hygrometer can help you track the relative humidity within your home. This way, if you notice humidity levels rising, you can open a window and allow fresh air to flow through your home to reduce humidity.
Small amounts of droplets on your window can also be an indication that you might need to open a window if it's not raining outside.
Does Drying Clothes Indoors Cause Condensation?
Yes. A load of washing dried on an airer releases around two litres of water into the air, which ends up on the coldest surfaces, usually the windows. Use a vented or condenser tumble dryer, or dry clothes in a ventilated room with the door closed and a window open.
Another great way to prevent condensation of aluminium window frames is by using a tumble dryer rather than hanging your clothes on a clothes horse.
A tumble dryer is used to dry wet clothes by blowing hot air into one side of the drum while the dryer spins the clothes extracting the moisture in the form of wet steam at the same time.
The condensation collects inside the dryer in a tank/tray and can later be cleaned out when you are done drying your clothes.
Do Trickle Vents Reduce Condensation?
Yes. Trickle vents in the window frame let a small, constant flow of air through the room, so moist air can escape without opening the window. They are especially useful in bedrooms, where breathing overnight produces a lot of moisture.
This can be installed underneath or on top of windows and can be used to cool the area with fresh air. The vent will provide a space for moist air to escape.
Why Is There Condensation on the Outside of My Windows?
Condensation on the outside of the glass is a sign your glazing is working well: the outer pane stays cold because heat is kept inside, so moist outdoor air condenses on it on cool, clear mornings. It is harmless and clears as the day warms up.
Aluminium window frames are designed to keep the heat within the house.
Condensation on aluminium window panes shows no air leak from the inside of the window. This is considered a good thing, as the window seals are working properly. As the temperature warms on the outside, the fog will clear up, and the window will be clear enough to see through.
You can also wipe down or rinse the window with lukewarm water to speed up the process. Ensure that the water is not hot, as it can cause a crack in the glass.
You can find more advice in our guide to aluminium windows explained.
Aluminium Window Condensation FAQs
How to prevent condensation on aluminium window frames?
Ventilate daily, run extractor fans and a dehumidifier, avoid drying clothes indoors and keep the heating steady. On older frames without a thermal break, a double-glazed, thermally broken replacement is the long-term fix.
What home remedies can I use to remove fog from windows?
Mix 2 cups of vinegar and 2 cups of water to make a solution that can be used to wipe down the windows and remove fog.
A homemade remedy is much cheaper than purchasing a dehumidifier; this solution can be pre-mixed to ensure that it is ready when needed.
Why is there condensation on my window?
Hot air mixing with cold surfaces is the reason for the fog on your windows.
Which aluminium windows are least prone to condensation?
It is important to install aluminium windows with double glazing. These are fitted with thermal breaks, which trap heat inside and insulate the house. This reduces condensation on cooler surfaces.
Does condensation create mould?
A build-up of condensation can create mould as the window panes and walls around the window are constantly damp.
It is important to check for any leaks or broken windows to ensure no mould is growing inside your home.
Do aluminium window frames cause condensation?
Modern thermally broken aluminium windows rarely cause condensation, because the insulated break stops heat escaping through the frame.
If you experience any condensation on aluminium window frames, you need to check the window frames for any faults.
Why is there condensation on the inside of my windows?
Condensation on the inside means the air in the room is too humid and the glass or frame is colder than the dew point. Cooking, showers, drying clothes and breathing overnight all add moisture. Better ventilation and a dehumidifier usually solve it; persistent condensation on the frame itself points to old, non-thermally broken aluminium.
How do you stop condensation on windows overnight?
Leave trickle vents open, keep the bedroom door ajar or a window on the latch, avoid drying clothes in the room and keep the heating on low rather than off so surfaces do not get too cold. A small dehumidifier running overnight makes a big difference in bedrooms.
Is condensation on windows normal in winter?
A little condensation on cold mornings is normal, especially on glass. Heavy daily condensation, water pooling on sills or condensation on the frames themselves is not, and should be dealt with to avoid mould. The same applies to doors; see our guide to condensation on aluminium bifold doors.
Can you insulate existing aluminium frames to reduce condensation?
You can improve them with secondary glazing, thermal tape or film, and by replacing worn seals. Our step-by-step guide to insulating aluminium window frames covers the options, along with draught proofing aluminium windows.
