How humidity damages your home — and how to fight it

Marie Bannister

Marie Bannister

August 1, 2023

Learn how to tackle excess moisture and dry air, which can both cause damage to different parts of your property. 


When humidity in your home is too high or too low, it can make living conditions unpleasant, and it can also do lasting damage to the property. 

High humidity creates excess moisture and condensation that potentially leads to mold or rot, while low humidity has been linked to the rapid spread of viruses like cold, flu, and even Covid-19.

In this article, we’ll discuss how bad humidity can cause damage to your physical property, fixtures, and fittings. We’ll cover how to tackle existing problems. and how to make sure the conditions are right in your home to prevent future damage.

What is humidity?

Humidity is simply the concentration of water vapor present in the air, while relative humidity measures the amount of water in the wait in relation to the maximum amount of water vapor it can hold. For example, when outdoor humidity reaches 100%, the air cannot hold any more moisture and it starts to rain.

In warmer temperatures, the atmosphere can hold more water vapor so, typically, turning up the heating in a room will cause relative humidity to fall. However, there are many different factors that cause these values to vary.

Drying laundry, a boiling pot, or a hot bath are all likely to cause humidity levels to rise, while ventilating a room properly will cause levels to fall, even though it generally makes the air cooler.


Airthings Humidity levels advice


Research from the Building Science Corporation found that humidity of 70% or higher adjacent to a surface can cause serious damage to the property. The Health and Safety Executive recommends that relative humidity indoors should be maintained at 40-70%, while other experts recommend that the range should be 30-60%. Most people find 30-60% most comfortable and this is the level that Airthings recommends.  

How high humidity causes damage in your home

High humidity can cause problems in your home if relative humidity regularly exceeds 60%. When the air contains water vapor above that level, mold and mildew start to grow, while excess moisture can cause rot, damaging your belongings. Let’s look at some potential problems.

Growth of mold and mildew

These microscopic fungi are all around us, but in damp parts of the home, they find the perfect conditions to settle on surfaces and grow. Mildew usually refers to the white or grey patches that form on surfaces like shower curtains, windowsills, or tiles, while mold is black or dark green in color and can penetrate deeper into building materials. 

Mold can cause health problems, like asthma in children, as well as triggering allergies.

If mold growth is not controlled, it eventually destroys the things it lives on, because the fungus gradually digests materials. This might mean that items like soft furnishings, books, carpets, or soft toys have to be thrown away. In more serious cases, it causes weakened ceilings or walls, and undermines the structural integrity of buildings.

Damaged paintwork and peeling wallpaper

The walls of your home are a prime site for condensation to gather, if high humidity is not controlled. The issue is particularly acute with exterior walls, as it’s here that warm, humid air meets a cooler surface.

Flaky paint or curling wallpaper is a sign of excess moisture in the home. It’s important not to just paint or paper over the problem without dealing with the damp, because it won’t go away.

Rotting furniture, floors, and furnishings

Excess moisture in the home due to high humidity can damage wood, either by creating stains and growths, or eventually by causing more serious decay. When furniture is placed close to outside walls, there is a higher risk that damp will set in.

In the most serious cases, when a problem with excess moisture goes on for a long time, it can cause irreversible damage to hardwood floors, window-frames, and other wooden fittings. 

Damaged walls and brickwork

The walls of your home will generally have air/vapor barriers, intended to prevent warm moist air penetrating the surface, but these are never perfect. Especially when the weather is warmer, moisture can condense in foundation materials, crawl spaces, and basements, leading to problems with the structure. 

When the moisture content in plaster, joists, or studs is constantly changing, it causes materials to swell or contract. As a result, high humidity can lead to cracks, which may call for potentially expensive repairs.

How to prevent high humidity in your home

The good news is that you can take some simple steps to deal with high humidity in your home, with the help of good quality information about the humidity levels in your property. 

The things we all do in our houses every day: washing clothes, taking baths or showers, cooking, and even breathing, generate moisture, but we can limit humidity problems in the home by minimizing this moisture and letting it escape.

Firstly, take steps to ensure that water can’t get into your home, by checking your roof and brickwork regularly, particularly after winter storms. 

Make sure your property is properly ventilated. That could be as simple as cracking open a window, but make use of fans and air conditioning too. This is especially important in rooms like the kitchen, the laundry, and the bathroom. When you’re cooking, use the ventilation hood, and activate extractor fans in the bathroom or laundry. 

Humidity causes fewer issues if your home remains properly and consistently heated. Try to maintain a relatively constant temperature, even if it means turning down the thermostat a little, but keeping the heating on for longer. As a result, there will be less opportunity for warm air to cool and cause condensation.

In addition, avoid drying clothes indoors, if you suffer from high humidity. Hanging wet towels or other items on radiators is a common practice that creates humidity as the moisture evaporates, increasing the risk of humidity damage in the home. 

Finally, by installing indoor air quality monitors you will be alerted to any potential problems, and have historical data, so you can see where persistent issues arise. Humidity sensors are an essential part of any air quality monitor, as they provide a detailed understanding of potential issues regarding moisture in your home. Avoid problems and optimize conditions with minimum fuss.

How to fix high humidity in your home

So if you already know that you have high humidity problems in your home, what can you do about it? Many of the prevention measures are also effective in dealing with existing issues.

Ventilation is key, and the simplest remedy is often to open windows. A more lasting solution could involve installing air conditioning, to get air circulating through your home, which will carry the moisture away. Alternatively, a dehumidifier draws moisture from the atmosphere, causing humidity to drop.

If you don’t have effective extractor fans in bathrooms or laundry rooms, or the ventilation hoods in your kitchen aren’t working well, you may need to repair or replace this equipment. Make sure that washing machines and tumble driers are plumbed in properly, and vented so that moisture escapes as it should.

How low humidity damages your home

How low should you let humidity get in your home? As we’ve discussed previously, ideally the figure should not drop below 30%. At lower humidity levels, the effects can include dry or itchy eyes, dry skin, and infections spreading more rapidly.

Dry, low-humidity air also causes physical damage to the home. Wood contains a certain amount of water, in ideal conditions, and when it loses too much moisture in dry air it experiences shrinkage. This can result in serious damage to flooring and furniture, or shifting window panes.  Low humidity can also generate excess static electricity, which sometimes affects electrical equipment and computers.

How to prevent low humidity in your home

To prevent low humidity in your home, you should find ways to add more moisture into the air. For example, you might want to leave a door open to let steam escape from the shower. Or you could choose to air-dry clothes indoors.  You could turn down the heat or boil a pot of tea on the stove. Think about investing in some pot plants too as they release moisture into the air. All of these actions will increase the humidity in your home. But be careful you don’t overdo it, and end up with a problem of high humidity as a result.

How to solve low humidity in your home

If you have persistently dry air, you might want to consider installing air conditioning or a humidifier to get the conditions right. To make sure that you’re doing the right thing, and to avoid going too far and encouraging high humidity, it’s important to understand the air quality in your home. 

An indoor air quality monitor will provide real-time and historical data on humidity, as well as other metrics, so you know exactly where problems exist and where they could potentially arise.


  • High humidity over 60% can encourage mold and mildew, and damage furniture, wallpaper, paintwork, floors, and brickwork.
  • To help combat high humidity problems, heat your home properly, use ventilation, and keep moisture-creating activities to a minimum. 
  • Low humidity causes wood to shrink, which can damage furniture, floors, and window panes. It can also affect electronics.
  • Heating and ventilation can help to control low humidity issues, while a humidifier stops the air from getting too dry.
  • Using an indoor air quality monitor gives you detailed data on humidity, so you can deal with issues and avoid damage to your property.














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