Nearly every home experiences condensation on windows (or other surfaces) at some time or another, mostly in the winter months, but not everyone understands why it happens. Even fewer people know that it can be detrimental to their health and cause a lot of damage to their homes!
As experts in the ventilation industry, the PIV Team has extensive knowledge of the subject, and we feel it's our duty to share this with you so you can take appropriate action to protect your homes and families.
Now, be prepared because we're going to go on a deep dive into this topic, as we want to provide you with as much information as possible. By the end, you'll not only understand why and how it happens but you'll also be furnished with everything you need to tackle your condensation problem.
And, in the unlikely event that we've missed anything here, feel free to check out our other blogs on the subject or get in touch, and we'll fill in any gaps.
If you're ready, let's get started...
Condensation, whether on windows or anywhere else, is simply a gas that's changing into liquid due to a change in air temperature.
When we breathe out on a frosty day, we can see our breath. That's because the oxygen has been warmed inside our lungs, and when it hits the cold air, it cools down and forms water droplets that hang in the air.
All air contains moisture to a greater or lesser extent. Warm air contains more moisture than cooler air, and when this warm, moisture-laden air reaches a cold surface, like your windows, it cools rapidly to form tiny droplets that create a sheet of mist across the window pane. This happens when the temperature of the glass (or any other surface) falls below the dew point (the point at which the air becomes saturated with water vapour and turns into liquid water).
When excessive moisture is present, the droplets accumulate and run down the glass as gravity pulls them toward the ground.
So, to recap, condensation occurs when gas turns into liquid, often on cold windows. It's a natural process that shouldn't cause too many problems, but if left unchecked, it can lead to some pretty serious issues.
We'll explore this in a bit more detail later, but first, let's dig deeper into the reasons why you get condensation in your home.
Delve into: How To Get Rid Of Condensation In Your Property
We've already given you a clue in the previous section as to why condensation forms, but where does all that moisture come from?
To answer this, we need to examine our lifestyles and habits. The following list perfectly illustrates how each of us contributes to the moisture content in our homes:
Although many of these only add a relatively small amount of moisture to the air, it all adds up. It is estimated that the average adult contributes between 10 and 15 litres of water per day to the atmosphere in their homes!
All that water and humid air has to go somewhere, and if your home doesn't have adequate ventilation and airflow, the excess moisture will condense on your walls and windows.
Explore: What Causes Condensation On Walls
In itself, when condensation forms on windows or other cold surfaces, it isn't such a bad thing. After all, it's just a bit of water vapour that's settled on the glass, so how bad can it be?
The fact is that a small amount every once in a while will do no harm at all. The real trouble begins when it is present in large volumes and starts to run down your windows and walls.
Let's examine the evidence:
Excessive condensation creates an ideal environment for mould and mildew proliferation. These fungi thrive in damp conditions, latching onto surfaces and spreading rapidly. Beyond mere cosmetic damage, mould and mildew pose substantial health risks (see below).
After a short while, your home will take on a musty smell as the mould spreads and emits spores.
You can find out more about this in our blog called Why Does My House Smell Musty, along with some great ideas for resolving the problem.
Condensation and mould are bad news for paint, wallpaper, and soft furnishings.
Black mould on damp walls will eventually stain paint and wallpaper, and no amount of scrubbing will get rid of it. You could use bleach, but this has its drawbacks, as we'll mention later. Your wallpaper will peel off and curl up, and you're often left with no other option but to replace it.
And when moist air penetrates inside soft furnishings and fabrics, they can begin to rot. Even if you can rescue them, they smell musty and damp. This includes soft toys, bedding, carpets, and curtains, as well as sofas, armchairs, etc.
In extreme cases, some unfortunate people have been forced to replace the whole lot, leading to heavy (and unexpected) expenses.
Prolonged exposure to condensation poses a serious threat to the structural integrity of your home. Wooden structures, such as window frames, beams, or even structural timber, can succumb to rotting when consistently exposed to moisture.
Moist air can penetrate deep into the hidden interstitial wall cavity from the outside during summer when there are warm outdoor temperatures, and from the interior during winter when the outdoor temperatures are cooler.
This excess moisture leads to penetrating damp, mould, and mildew that can spread undetected for many years without any visible surface indications, causing untold (and very expensive) damage.
Even uPVC frames can be adversely affected if the stagnant water and mould sit for too long, leading to the degradation of the plastic. This degradation weakens the framework, compromising its stability and safety. Double-glazed windows can blow, meaning that the seal around the edges has been breached, rendering the insulation useless. One sign of this is condensation inside the gap or a whitening of the glass.
Moreover, condensation-related moisture can seep into walls, damaging plaster, paint, and wallpaper. Over time, this deterioration necessitates extensive repairs, often incurring significant financial costs.
Condensation not only harms structural elements but also impacts the efficacy of insulation materials. When moisture infiltrates materials like fibreglass or foam insulation, their ability to trap heat diminishes. This reduced efficiency compromises the thermal insulation of your home, leading to increased heat loss during colder months. As a consequence, heating systems work harder to maintain desired temperatures, resulting in higher energy bills and reduced overall comfort within the household.
Condensation-induced mould spores can be a considerable health hazard. These microscopic particles become airborne and circulate throughout the home, potentially posing health risks to its occupants. For individuals with respiratory conditions like asthma or allergies, exposure to mould spores can trigger or exacerbate symptoms. This exposure can lead to chronic respiratory problems, allergic reactions, and in severe cases, respiratory infections or compromised lung function. Babies, toddlers, and the elderly are more vulnerable to the effects than most others.
Protecting against these health hazards requires vigilant moisture control and effective management of condensation to inhibit the growth and dissemination of mould spores.
Also known as internal fogging, this is the formation of moisture droplets on the exterior surface of a window pane. It occurs when the outer pane of the glass cools down to a temperature below the dew point of the surrounding air, which is the temperature at which the air can no longer hold all of its moisture and starts to condense out on the cold glass.
This phenomenon is more common in newer homes with energy-efficient windows, as these windows are designed to prevent heat from escaping from the home, which can lead to colder temperatures on the exterior surface of the windows. It's not usually a cause for concern, as it is simply a sign that your windows are doing their job of keeping your home warm.
Here are some factors that can contribute to exterior window condensation:
We can simplify the solution by breaking it into three parts:
Once you've got this, you'll have the upper hand, and your condensation and mould issue will soon be a thing of the past.
All you need now is some advice on how to do this, and that's exactly what we're about to offer.
Getting rid of condensation completely is possible if you adopt a multi-pronged approach and combine several methods.
We've pulled a few of the most common - and most effective - ones for you to consider:
Ventilation is vital for eradicating condensation. Natural ventilation, such as opening windows, facilitates air exchange, while trickle vents, window vents, and extractor fans ensure controlled airflow, reducing relative humidity without substantial heat loss. Extractor fans in kitchens and bathrooms expel moisture-laden air directly outside, preventing its build-up indoors.
The PIV Team believes that ventilation is the primary factor fighting condensation on windows and wall surfaces. This forms the core of our expertise, as we specialise in the professional installation of Positive Input Ventilation (PIV) systems - a straightforward yet ingenious solution that effectively eliminates condensation in the majority of homes.
We'll elaborate on this subject later, but first, here are some more tips on reducing condensation.
We've touched on this one already, so we won't dwell on it for too long. The key here is to invest in good-quality double glazing and to watch out for signs of deterioration or damage.
Condensation inside double glazing typically suggests that the sealed unit has been compromised, so the window will need replacing.
For those with single-glazed windows, it's best to install double-glazing if at all possible, as this will help to eliminate condensation. If your budget allows, you might want to look into triple-pane windows, as these offer superior insulation and will drastically reduce the chances of condensation forming.
Finally, we need to talk about wooden window frames; while new ones look attractive, it's imperative that the wood is treated and maintained carefully. They are generally more expensive than uPVC and, therefore, require a higher investment.
Older wooden window frames are highly susceptible to condensation and mould, and they tend to rot. If possible, invest in new windows and doors that offer better insulation and protection. This will reduce the air infiltration flowing into your home and provide a much better seal, making it more energy efficient and helping to reduce condensation.
Choose a good one that's the right size for the room or the entire property, but check the wattage carefully, as some can be expensive to run.
Dehumidifiers help to stop condensation by pulling excess moisture from the air. Most people are surprised by the volume of water that is collected, even within a couple of hours! You don't need to keep it running all the time; even if you only use the dehumidifier at strategic times during the day, this will reduce condensation in the home.
Get a large bathmat to avoid saturating bathroom floors, take shorter baths or showers (this also helps to lower your energy bills!), and keep the bathroom door closed to stop the excess humidity from escaping into the rest of the house.
Make sure you open windows and/or switch on the extractor fan if you have one. Also, the extractor fan should be adequate for the size of the room.
Don't overfill pots when boiling your veg, and keep the lids on to avoid filling the kitchen with water vapour. Use a cooker hood or extractor fan whenever possible, as these filter out the humid air or force it outside.
Controlling condensation is key, which is why it's advisable to close the kitchen or bathroom door while cooking or bathing, as these are the rooms where most water vapour is created.
Set large pieces of furniture, like sofas, armchairs, and sideboards, away from the wall by at least 20cm to allow air circulation. Placing furniture directly against the wall causes cold spots where condensation can appear
Fix leaking pipes or leaks and gaps in the building fabric (like broken roof tiles, cracked window frames, broken downpipes, etc.) where water can get in, as excess moisture enters your home this way and contributes to your condensation problem.
Check that air bricks are not blocked up, and make sure your damp-proof course is sound.
Once all this is done, you can apply some of the other measures to combat condensation and mould.
This specialist paint effectively adds another layer of insulation to the wall or ceiling. Technically, they're not 'anti-condensation', as they don't actually stop condensation. Instead, they keep the surface above the dew point temperature to delay the formation of internal condensation.
When the humidity levels rise, the paint absorbs moisture and stores it until the humidity drops, at which point it releases the moisture as water vapour.
Of course, this remedy won't prevent condensation on windows as such, but it will reduce condensation overall in your home.
It's also worth keeping in mind that any of these paints only remain effective for around five years, after which you'll need to reapply them.
It's important to make sure that all domestic appliances are ventilated well, but a tumble dryer should ideally be fitted to an external vent. Otherwise, all that hot, humid air will blow around your home and cause condensation on windows.
It's also wise to invest in a cooker hood with outside ventilation, and all fireplaces, flues, and gas fires should be vented outdoors in order to prevent carbon monoxide poisoning and condensation on windows.
How does rearranging furniture stop condensation on windows? Condensation happens when there's too much humidity, and the moist air condenses on window glass and other surfaces. When large pieces of furniture are placed too close to the wall or close together, they can block the passage of air and cause cold spots of moist air.
Leaving a gap between furniture will help to reduce moisture, even if only in a small way, but it all adds up!
And now, we'll return to the subject of ventilation, as promised, to give you an ideal solution to your condensation problem: the Positive Input Ventilation system.
Positive Input Ventilation (PIV) represents a fantastic method for enhancing indoor air quality. Essentially, these devices are crafted to draw out stagnant air and replace it with fresh, filtered air continually, aiming to reduce condensation.
The concept behind PIV is to promote the flow of air from the inside to the outside.
Dig Deeper: What Is A PIV Unit
Positive input ventilation units function by drawing fresh, filtered air from outside your home and gently introducing it into the living spaces. This creates a slight positive pressure inside the home, expelling stale air through existing vents, cracks, and openings. This ongoing process refreshes and replaces stagnant air, thereby enhancing the overall air quality inside your home.
Learn more: How Does A PIV Unit Work
Here's a more comprehensive breakdown:
The PIV unit is usually installed in a loft space (although wall-mounted versions exist), where it draws in fresh air from outside through an external intake vent using a small fan.
The incoming air passes through a filtration system to eliminate dust mite allergens, pollen, and other airborne pollutants, ensuring that the air entering your home is clean and healthy.
The filtered air is then channelled throughout the house via a network of ducts or tubes, often concealed within walls, ceilings, or floor joists.
The PIV unit introduces filtered air into the living spaces at ceiling level, at a slightly higher pressure than the existing air inside (unlike extractor fans that create negative pressure).
The positive pressure drives stagnant air out of the home through trickle vents, cracks, and openings like window gaps, door openings, and extractor fans.
The PIV system operates continuously, ensuring a consistent supply of fresh, filtered air while gradually replacing humid, stagnant air, contributing to a healthy and comfortable indoor environment.
Therefore, PIV systems function by delivering fresh, filtered air into your home while simultaneously expelling stagnant air. This continual ventilation process enhances indoor air quality by reducing condensation and airborne indoor pollutants, creating a healthier living environment.
Positive input ventilation systems offer numerous advantages over other solutions:
PIV systems introduce fresh, filtered air into your home, diluting pollutants, allergens, and odours. This can improve respiratory health, reduce allergy symptoms, and foster fresh, pleasant living environments.
PIV systems help control humidity levels, eliminating surface condensation; mould thrives in such conditions. Black mould can cause respiratory problems, skin irritation, and allergic reactions, particularly with prolonged exposure.
PIV systems can reduce energy costs by pre-warming or pre-cooling incoming air before it enters your home. This means your heating/cooling system won't have to work as hard to maintain a comfortable temperature. Properly running PIV units should not make your house cold.
PIV systems provide ventilation to all areas of your home, not just rooms with open windows, eliminating "dead spots" with poor air circulation.
PIV systems are typically very quiet, making them suitable for noise-sensitive homes.
PIV systems require minimal maintenance. Filters should be cleaned every 3-6 months and replaced every five years or so, and the system should undergo annual inspection.
Additional benefits of PIV systems include reducing the risk of respiratory infections by circulating fresh, filtered air, improving sleep quality by creating a comfortable sleeping environment, saving money due to low running costs, protecting your home from structural damage caused by condensation and mould growth, and increasing the value of your home by making it more appealing to potential buyers.
Uncover more: Health Benefits Of PIV Units
Well, now you know what causes condensation on windows, and you also know the damage it can do to your health and your home.
You also now know exactly how to fight back and beat it for good by combining the above methods with a Positive Input Ventilation unit.
The PIV Team will help you find the perfect PIV unit for your home, meaning that you can say goodbye to streaming windows, black mould, musty odours, and mildewed soft furnishings.
Join the PIV Team, and let's make condensation history!
