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Condensation Control Services

Condensation or humidity damp is usually misdiagnosed as rising or structural damp by all sorts of property industry stakeholders and especially trade intermediaries (builders, electricians, damp proofers) usually because of a complete lack of knowledge and understanding of humidity damp and its causes. In fact condensation or humidity damp is by far the most common damp issue in modern British properties and is behind all strategic damp problems (condensation and black mould in winter, lingering odours, clothing / paintwork / plastering taking a long time to dry), unlike rising or structural damp which is local to where the defect is.

Condensation is an increasing problem in both modern and older properties as we retrofit insulation improvements to save money and progress toward Net Zero. Modern lifestyles and the need to conserve energy/fuel services contribute to the problems but the biggest issue is the ventilation strategies millions of British properties are built with which are behind every single strategic condensation and mould problem in Britain.

The widespread lack of knowledge and understanding is truly shocking and is why all the advice and guidance doesnt help and repeated cleaning and other mitigation works dont work leaving occupiers/owners frustrated, at a loss and exposed to further cost, property/belongings damage and health risk. The Awaab Ishak tragedy is a terrible example of this. It is evident everywhere from surveyors, architects, social housing and private sector property managers, letting/managing agents, landlords, tenants, homeowners and especially the trade to job posting websites where damp issues are misdiagnosed and contractors are portrayed as expert because the website itself also doesnt know or understand how to distinguish damp issues.

Better Indoors has complete knowledge and understanding of condensation and humidity damp issues.

A simple explanation of condensation

Warm air will hold more moisture than cold air. When the warm air is laden with moisture this in itself does not cause a problem. The problems start when the air starts to cool down. As the air cools down it cannot hold the moisture, so when it comes into contact with cold surfaces liquid water will appear.

The obvious places for condensation to occur are on cold windows, walls and floors, but it can also occur in roof spaces and in sub floor areas where there is a timber suspended floor. In the latter cases, it can lead to dry rot or wet rot developing in floor and roofing timbers. Note this phenomena is often diagnosed as water leaks/ingress by stakeholders without this understanding.

Do you have problems with condensation?

With as many as one in five properties in the UK having a problem with condensation, it’s no surprise that your home may have the same problem. As a significant and common reason for damp problems in buildings, houses and flats, condensation can easily lead to long-term health issues, damage to property and other issues if left unchecked.

How does condensation appear?

Condensation is caused by two specific elements working together: lack of ventilation retaining moisture produced by building occupants and cold weather. Many of our daily activities produce moisture, from boiling the kettle to taking a shower to drying clothes. If there is nowhere for that moisture to go, it’s stuck inside with us, leading to the visible effects and long-term problems with condensation. Double and triple glazing and draft proofing may make our homes warmer in the winter, but they also leave no way for that moisture to get out of our homes through air ventilation.

What are the tell-tale signs of condensation?

You can usually spot condensation on windows and mirrors when it first appears. Water droplets on these surfaces, as well as on walls or ceilings, are perfect examples of condensation. While a bit of condensation now and then is unlikely to cause long-term harm, the longer that moisture is trapped, the more damage it can do. Often, you won’t notice the effects of condensation in your household until you spot damp or black mould growing on your windows, walls, or ceilings. In some cases, peeling wallpaper and paint can suggest that your walls are becoming too damp from condensation in the air (rather than leaks or ingress). If you spot any of these tell-tale signs, it’s important to act. Leaving a condensation problem to become worse can quickly lead to larger damp and mould problems, which in turn can lead to health issues and damage to your belongings.

How do you stop condensation?

The only way to stop a strategic condensation problem is to control the indoor relative humidity and keep it a levels where the thresholds required for condensation, mould and other humidity problems such as dust mites, are not reached. This requires a properly specified ventilation performance improvement retrofit without the heat loss that comes with opening windows, air bricks or trickle vents which is at the heart of the problem in millions of British homes. Such a system not only permanently eliminates and prevents condensation and mould but it also improves indoor air quality which leads to improved health, wellbeing and productivity and saves ££££ as windows, airbricks and trickles can be kept closed throughout the colder months. Better Indoors has supplied and fitted thousands of such retrofits over the past decade. We are experts in surveying, specifying and installing and there is so much more to it than simply buying a good quality unit from a wholesaler and asking your electrician to fit it.

How do you control condensation in dwellings?

For homes of all shapes and sizes, effective condensation control is a must to avoid strategic damp issues. This is especially important in bathrooms, kitchens, and other wet room spaces where moisture producing activities and ineffective extraction ventilation combine to cause excess condensation. However, the most important and most overlooked process is the strategic background ventilation which generally underperforms and is the main cause of strategic condensation and mould problems. Better Indoors condensation control systems ensure sufficient performance improvements to permanently prevent condensation and mould whilst saving ££££ in lower energy costs as windows, airbricks and trickles can be kept closed all through the colder months. If you own a multi-unit property or live in a flat or apartment, seeking the right sort of professional help is essential to remove problems with condensation effectively. Multi-dwelling properties often have issues with damp, in part due to lifestyle and in part due to poorer ventilation. Better Indoors can support you by specifying a condensation control solution to effectively displace and dilute moisture-laden air.

How do you control condensation in a building?

For commercial buildings and industrial properties, it’s equally as important to handle condensation as it is within a dwelling. Condensation in offices and public facilities can worsen in the cold months, particularly if draft-exclusion measures are in place. You may also find that older buildings have windows painted shut and lack proper ventilation to prevent condensation and dampness. To effectively remove condensation, professional condensation control can give you the best solution. Our condensation control solutions dilute moisture content in the air, reducing relative humidity and preventing humidity damp throughout buildings of any shape and size. Our expert technicians will specify the ideal solution for your building, whether it’s a large-scale property or a small office.

Will ventilation stop condensation?

Ventilation is crucial to prevent condensation in your home or building. Ventilation strategies are poorly understood by many in the trade, from the most basic ones that almost all properties are built with to the most complex ducted strategies. A properly performing system must comprise effective extraction and supply ventilation and there is so much more to this remark than simply a good quality product. The more complex ducted strategies are becoming more commonplace for new builds given Net Zero and the drive for improved IAQ since COVID (whether they are specified and installed properly is a different discussion). For older properties and those with underperforming ventilation strategies and significant heat loss, a Better Indoors whole home retrofit is the ideal choice that stops condensation and saves £££ in wasted energy costs.

Do you need help with condensation, mould, or damp problems?

If you have condensation and mould in your home and it only happens during the colder months of the year then you have a strategic humidity problem which requires expert attention and not guesswork. With over a decade of experience in permanently solving condensation and mould in all types of properties up and down Britain, Better Indoors will ensure your issue is accurately diagnosed, specified and resolved quickly and effectively.

Why Does Humidity Rise When It Rains?

does rain increase indoor humidity

Many people know that humidity rises as rain rolls in. With a quick step outside you can feel the difference, but does rain increase indoor humidity?

The short answer is yes; rain increases indoor humidity.

With rain comes humidity, and for many people that spells trouble.

Curly-haired folks can expect a bad hair day and people with arthritis have a little extra discomfort, but that’s not the only issue with high humidity indoors.

As rain falls, it evaporates and adds water vapour to the air, increasing the humidity. Since you can’t keep that air outside, the humidity levels in your home rise as well.

why humidity rise

While humidity is a common term, not everyone knows what it means.

Even if you don’t know how to explain it, you probably know the feelings that come with high humidity.

The air can feel thick and sticky wherever you go. That thick feeling comes from excessive water in the air.

What? How does that work?

Water might be most recognizable as a liquid, but it can freeze into ice or evaporate into a gas.

The gaseous form is known as water vapour, and it can hang in the air giving it that dense feeling we know and love.

Humidity rises as water vapour overloads the air. If the humidity climbs too high, it prevents other moisture from evaporating.

But, Why Does Rain Increase Indoor Humidity?

why rain increase humidity

When you walk outside during, before, or after a rainstorm, you will likely notice that the air feels different.

You might notice that your sweat doesn’t evaporate and leaves you feeling sticky.

If it rains enough and fills the air with too much water vapour, there’s no room for anything else to evaporate, including sweat.

While the effect is most apparent outside, it also occurs indoors.

Since you can’t completely seal a building to prevent air from moving in and out, the humid air works its way inside.

What Affects the Humidity Levels?

affects humidity level

Did you know that there are different ways to discuss humidity in the air?

Absolute humidity is an exact measurement of how much water vapor exists in the air.

Also known as specific humidity, it appears as grams of water vapour for each cubic meter volume of air.

It’s a technical measurement but doesn’t account for air temperature.

Relative humidity refers to the percentage of water vapour in the air at any given temperature (must be expressed like this because the amount of water vapour air can hold at any given temperature is different - as the temperature drops the amount of water vapour it can hold drops and vice versa)

High humidity percentages indicate a higher saturation of water vapour in the air.

Warmer air holds more water vapour than cold air, so you notice the sticky, sweaty effect in summer more than in spring.

Another way to discuss humidity is the dew point. The dew point refers to the temperature the air needs to reach to achieve saturation or 100% relative humidity at that temperature.

Once the air drops below the dew point, the water vapour condenses and leaves droplets behind.

Tip: Remember two important things. First, a high relative humidity means there is a lot of water vapour in the air. Second, a high dew point means the air can hold more water vapour.

How Is Humidity Measured?

measure humidity

Relative humidity is a metric that is measured and calculated by how much water vapour is in the air.

This is measured in a range of 0-100%, and humidity levels will be expressed in percentages.

On a severely dry day in a dry climate, such as the desert, the humidity will be at 0%.

On a wet and rainy warm day in a humid environment such as a rainforest, humidity could be at 100%.

People use hygrometers to measure humidity. Meteorologists use the device to determine how much moisture is in the air at any given point.

There are several different types available depending on how precise somebody needs to be and their preferred approach.

Most homeowners opt for easy-to-use digital hygrometers that take readings and display them on digital screens. They are relatively easy to find at a home improvement store, big-box store, or online.

Note: Some thermostats actually feature digital hygrometers to make your life easier.

How Does Humidity Work Indoors?

how humidity work

You can see evidence of the outdoor air dropping below the dew point outside.

You might notice droplets of water on the grass and other surfaces, but what about inside?

The dew point doesn’t apply to outdoor air. Every building needs to regulate the amount of water vapour in the air to prevent it from reaching saturation.

While it’s not going to rain in your house as it does outside, once the air can’t hold any more water, it has to go somewhere!

Water droplets on large surfaces, including your basement walls, can indicate a problem.

Condensation inside indicates a moisture control issue that can cause a range of issues.

Excessive indoor humidity causes mould and mildew to grow, damages walls and furniture, causes dust mite populations to increase leading to asthma trigger and asthma conditions to develop in young lungs and instigate allergies, and even ruin the brickwork and coverings.

Note: Don’t freak out if you notice a little condensation on the side of your glass of ice water, that’s normal and doesn’t indicate excessive humidity.

What Is the Best Indoor Humidity Level?

best humidity level

The ideal indoor humidity level is around 40-60%. Less than that may dry out your skin or impact your health by causing dry noses or throats.

More than that amount of moisture can cause mould growth and dust mite increases in the home, both of which will lead to serious health consequences.

Can You Regulate the Humidity in Your House?

As we have discussed, rain can increase indoor humidity.

But, that doesn’t mean there is nothing you can do to lower your humidity levels to avoid any negative impacts on your home or your health.

It’s a good idea to pick up a hygrometer to track your humidity levels.

Once you get an idea about your humidity levels, it’s easy to figure out how to regulate them.

How To Decrease Humidity in a House

decrease humid in house

Areas that see a lot of rainfall might have issues with moisture buildup in their homes.

Thankfully, there are some handy appliances and tricks to pull excess moisture from the air and keep humidity levels in check.

Running the heat or air conditioning naturally dries out the air, making it a helpful option for people dealing with temperature and moisture issues.

It also reduces the amount of outdoor air making its way inside because you close up the house when running the HVAC system.

Keep in mind that maintaining your HVAC system and air filters is crucial to your home health.

Also, you should always have proper ventilation systems and keep your home at an appropriate temperature.

Note: Make sure you watch for signs of increased moisture in case you need to make adjustments.

How to Increase Humidity Indoors

increase humidity

It’s important to note that some places struggle to reach saturation and even maintain a healthy level of water vapour in the air.

Dry climates might need to add moisture to the air inside because there’s so little water around. Installing a humidifier is the best solution.


Rainy days can ruin outdoor events, cause bad hair days, and even leave you feeling less than your best but does rain increase indoor humidity?

Yes, rain can increase indoor humidity.

Typically, light rain won’t increase the humidity in your home, but at a certain point, excess rain will cause your home to have more humidity.

It’s common to experience high humidity in a house after rain, especially in a heavy storm.

High humidity levels in a house can have significant negative impacts on the building and your family.

Thankfully, it’s easy to monitor humidity levels and there are devices to help regulate the water vapour in the air.

Now, you’re ready to handle this situation head-on and ensure that rainy days don’t impact your health or your home’s structural integrity over time.

Why Do Some Drinks Sweat?

Science can be seen everywhere, and it can be a lot of fun. Just take a look at today's video or another EepyBird Diet Coke® and Mentos® experiment. That's really cool! And scientific. Today's Wonder of the Day is also about liquid science, but it won't create such a big mess!

What happens when it's hot outside? You just finished your chores for the day. You mowed the lawn, raked leaves, and then picked up branches in the yard for almost two hours. You're tired…and thirsty! What better way to rest on a hot day than with a tall, cool glass of lemonade on the front porch.

You slowly sip your lemonade and relish its sweet and tangy flavor. The cold liquid cools you from the inside out. You set your glass aside and close your eyes for a few moments.

When you reach for your glass again, you notice that it's wet on the outside. Tiny drops of moisture have formed on the outside of the glass. They slowly bead and drip down like the sweat on your forehead. You knew it was hot out, but is your glass really sweating?

Not quite! It may look like sweat, but that's water on the outside of your glass of lemonade. But how did it get there? Did it just magically appear out of thin air?

Actually, it DID come right out of the air, but there's nothing magical about it. It's all science! In fact, there's a scientific name for what happened. It's called condensation.

Whether you realize it or not, there's water in the air around you all the time. Instead of liquid water, it's a gas called water vapor. Warmer air can hold much more water vapor than colder air.

When water vapor in the air comes into contact with something cool, such as the outside of a cold glass of lemonade, its molecules slow down and get closer together. When that happens, the gaseous water vapor turns back into liquid water droplets. That's condensation!

If you wear glasses, you may have noticed condensation in another form. If you've been wearing your glasses inside where it's cool and suddenly walk outside where it's warm, you may have noticed your glasses fog up. This is the result of the water vapor in the hot outside air suddenly condensing on your cooler glasses.

Particularly during fall and spring, when temperatures vary more than at other times of the year, you may notice condensation on the walls or windows of your house. You can also see it on the windows of your car. These are all examples of the same scientific process of condensation.


Wonder What's Next?

Tomorrow’s Wonder of the Day is a real cry for help!

Try It Out

If you're ready to take your learning about sweaty drinks to the next level, check out one or more of the following activities with a few friends or family members:

That condensation on your beer can might not be a good sign

We've all seen a cold beer can sweat in the summer heat. Now, a new scientific study reveals the surprising effect that layer of condensation has on the temperature of your beverage.

If you're familiar with evaporative cooling, there's a chance you guessed that moisture keeps your can chilled. After all, when people sweat, we experience a cooling effect. Transitioning from a liquid phase to a gaseous one requires the input of energy; as the beads of moisture on our skin evaporate, that energy comes from our bodies in the form of heat, cooling us in the process. So is this what happens to a chilled beverage on a hot, humid day? Nope. In fact, it's the exact opposite.

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Contrary to the colloquialism, a cold can of beer or soda doesn't actually "sweat." In reality, gaseous water is condensing out of the air and clinging to your beverage in its liquid phase, undergoing a transition in the direction of gas → liquid, rather than liquid → gas. The thermodynamic opposite of evaporative cooling, this process actually expends energy in the form of heat, which is absorbed by your brew.

“Probably the most important thing a beer koozie does is not simply insulate the can, but keep condensation from forming on the outside of it,” said Dale Durran, a University of Washington professor of atmospheric sciences.

Durran is co-author of a study published in the April issue of Physics Today that shows, in impressive detail, how humidity can have a dramatic effect on the temperature of a chilled beverage. The experiment started in the bathroom of co-author Dargan Frierson, where the pair used a space heater and hot shower to vary temperature and humidity. After confirming Frierson's back-of-the-napkin calculations (the heating effects of condensation are well-known, albeit untested with beer cans, specifically) the pair turned to more rigorous experimental methods. “You can’t write an article for Physics Today where the data has come from a setup on the top of the toilet tank in one of the author’s bathrooms,” said Durran. Their findings are summarized in the figure below.

Via Durran and Frierson: The temperature rise (δT) of water in a 12-fluid-oz can depends on relative humidity and ambient temperature. In this plot, each filled circle represents the change in temperature, after five minutes, of water initially near 0 °C for ambient temperatures of 25 °C (blue) and 35 °C (red). Open circles show the portion of the temperature change due to latent heating.

The plot illustrates that a chilled 12 oz can of liquid refreshment warms more than twice as quickly in humid environments than it does in more arid climes, a finding that the following video – created by students in the University of Washington's Department of Atmospheric Sciences – really drives home:

So what does condensation on a chilled can have to do with atmospheric sciences? "Condensation as a heat source is just tremendously important," Frierson told NBC News. "It's really like the gasoline that powers hurricanes, thunderstorms and tornadoes." That's an important connection – some climate models predict that rises in atmospheric humidity in the years ahead could lead to an increase in these extreme weather events.

"We want people to appreciate how powerful this effect is," said Durran. "A very thin film around the can makes a big difference in the temperature of its contents, and that just makes you appreciate the importance of that same heating effect in our atmosphere."

The results of the study are available free of charge at Physics Today.

How to Keep Your Windshield From Fogging Up

You’re driving down the highway and your car’s windshield fogs up, so you blast the defroster. The fog goes away but then returns again a few minutes later. You repeat this process until you arrive at your destination.

The same thing happens to the car’s driver- and passenger-side windows. The windows fog up so you can’t see your rearview mirrors, so you roll the windows down and then back up to squeegee the moisture off. But then the fog simply comes back again.

And on the fight against vehicular window fog, and its visibility-robbing haze, goes.

Fortunately, there’s a way to escape this seemingly endless cycle of fog recurrence and achieve driving nirvana. We share your exit strategy below.

Why Does Your Windshield Fog Up?

To understand how to prevent your vehicle’s windshield (and windows) from fogging up, it helps to understand why they fog up in the first place.

Fog on the inside or outside of your car windshield is condensation that forms due to a difference in temperature and humidity near the glass. The nature of this differential varies according to the season of the year.

During the winter, window fog typically occurs inside of your car. That’s because the temperature and humidity on the inside of your vehicle are higher than they are outside of it. All that hot vapor from the passengers’ breath condenses on the inside of the windows/windshield once it hits the cool glass.

When you experience foggy car windows in the summer, the condensation usually occurs on the outside of the car windows. That’s because the temperature and humidity on the outside of your car are higher than on the inside where you’ve got the cold, dry A/C running. Once the hot, moist summer air hits your car’s windows, condensation forms on the outside of the glass.

Knowing where the condensation is forming — inside or outside — will guide how you implement your preventive anti-fog measures.

How to Keep Your Windshield From Fogging Up

Clean your windows. The first step in preventing automotive fog is to give your vehicle’s windows and windshield a nice wipe down. Dirt and oils on the glass will attract and maintain condensation. Clean your car’s windows/windshield on both sides with some window cleaner and a newspaper or paper towel.

Apply an anti-fog spray. Anti-fog spray contains chemicals that prevent water from condensing on your glass.

Remember, if it’s winter, the fog will be forming on the inside of your windows/windshield, so make sure to get a spray that’s designed for interior glass.

If it’s summer, you’ll want to apply the anti-fog spray on the outside of the glass and you’ll want to use a product designed for the exterior.

Thoroughly cleaning your windows before applying anti-fog spray is a big key in their efficacy, so don’t neglect the step one recommendation above.

Use home anti-fog remedies. If you don’t want to go to the auto supply store or have a bottle of commercial anti-fog spray Amazon Primed to you, there are some home remedies you can use to prevent fog from forming on your glass:

Turn off the recirculate button on your air-conditioner/heater. You’ve likely seen this button on your car’s console but may never have really understood what it did. When the recirculate button is engaged, your vehicle uses air from inside your vehicle for heating and cooling; it continually recirculates the same air, allowing it to be heated/cooled more effectively. When the button is off, the car heats and cools using air brought in from the outside.

If condensation forms on the inside of your car during the winter, you can probably see why it would be a bad idea to recirculate this warm, moist interior air. It just perpetuates the fuel that feeds windshield fog.

So make sure the recirculate button is off.

Turn the heat and A/C on at the same time. When it’s cold outside, you want the heat on in your car so that you’re warm. But warm air causes condensation to form on your windshield. So how can you stay warm without fogging up the glass?

Turn the A/C on at the same time as you crank up the heat in your car.

The A/C  will dry out the air. By reducing the moisture in the warm air blowing in your car, you reduce the likelihood of your windshield and windows fogging up.

Just make sure your car’s A/C button is on when you crank the heat up. That’s all there is to it. And no, this won’t damage your car’s air-conditioning.

When all else fails, blast the defroster to the max. If you’ve done all these things, and you still get some fog, you can always turn the defroster up to full blast. The warm, dry air will evaporate the moisture on the interior of your windshield, defogging your glass immediately. This is a temporary fix, though. If the humidity is still high inside your car, you’ll just get a foggy windshield again. Make sure the recirculate button is off, and try re-cleaning your windows/re-applying anti-fog spray when you return home.