How to stop condensation

Condensation is the easiest damp problem to fix. It can often be solved cheaply and quickly, without the need for professional help. 

Read on to find out what causes condensation, how to get rid of it – in both the long and short term – and what to do if you have a serious condensation problem. 

Be inspired to make home improvements. Sign up for our Home newsletter – it's free monthly

What causes condensation?

Condensation is caused when humid air meets cold surfaces, such as walls and windows.  

When the temperature goes down, the amount of moisture that the air can hold falls and the tiny drops of water form on the surface.

The amount of moisture in the air is increased by the release of water vapour from cooking, bathing and showering, and even respiration. 

If condensation is allowed to sit on walls for long periods of time, it can penetrate the outer layers of your walls and seep into furniture where it becomes a longer-term problem, causing mould to grow.

How to stop condensation

There are five things you can do to help prevent condensation in your home:

1. Clear existing condensation
2. Limit the amount of moisture produced in your home
3. Improve your ventilation
4. Upgrade your insulation
5. Make sure your heating is set up sufficiently

1. Clear existing condensation

In the short term, make sure you clear your windows of condensation regularly so it doesn't cause damage or develop into mould. 

You can do this easily with a towel, tissues, a squeegee or window vac. 

We've put window vacs from brands like Karcher, Beldray and Salter to the test to find the best window vacs.

2. Limit the amount of moisture produced in your home

When you can, always try to limit the amount of condensation produced in your home. Your bathrooms and kitchen are responsible for most of the moisture. 

If you don't have an extractor fan in your bathroom, you should consider having one installed and making use of it each time you shower or bathe. Check out our guide on how to buy the best bathroom extractor fan.

In the kitchen, it’s a good idea to keep lids on pans when cooking, but a good cooker hood can be an effective way of reducing a build-up of condensation while cooking. Extraction hoods, which send air outside through ducting, are generally most effective at removing steam and moisture. 

The best will work quickly and quietly to eliminate moisture and odours, while stopping grease from forming on your kitchen surfaces. Check out our guide to the best cooker hoods to find out more. 

It’s also worth considering a dehumidifier, which will draw moisture out of the air. These can be particularly useful if you often dry clothes inside the house – another common source of excess humidity. 

There are different types and brands available, so read our guide to the best dehumidifiers to find the best one for your home.

3. Improve ventilation

Better ventilation helps to reduce condensation problems. This can be as simple as remembering to open windows when you're at home or, especially when cooking, washing up or showering, or if you need to dry clothes indoors. If you have windows that lock when partly open, leaving them like this more often will help. 

For a more permanent solution, ventilation options include:

• Building air bricks (made with small holes) into outside walls. 
• Installing air vents through internal walls or sealed chimneys to allow airflow through the house.
• Fitting roof ventilation tiles and/or ventilated soffits (under the roof and guttering) to allow air through the loft.
• Adding window vents to the tops of window frames.

Bear in mind that these measures may mean that some heat is lost from your house, so balance that against your damp issue. You may want to consult a specialist to check the best course of action.

Whole house ventilation

For more serious condensation problems, there are bigger systems available that claim to improve ventilation.

EnviroVent, a Which? Trusted Trader that specialises in whole-house ventilation systems and extractor fans, recommends a system called positive input ventilation (PIV). It draws fresh air from outside a building in and then distributes it into all rooms through a centralised system that is usually mounted in the loft. 

'A conventional extractor fan that you might find in a bathroom or kitchen is an effective way of removing humid air from a building to reduce the condensation that causes damp; however, an extractor fan simply removes air,' says EnviroVent. 

'A PIV closes the loop of airflow by controlling and filtering the air that is drawn into the building to replace the humid air that is removed by the extractor fan. A PIV is a whole-house ventilation system that improves air quality in all rooms.'

Use Which? Trusted Traders to find a local ventilation specialist vetted by Which?

4. Upgrade your insulation

Cold spots on walls or ceilings increase the likelihood of condensation, so better, more consistent insulation can be a good solution. Cavity wall and loft insulation, or having specialist insulation materials fixed to the outside of your house can all help. 

Keep in mind that in some circumstances cavity wall insulation can be the cause of damp, but this tends to be rare. See our advice on penetrating damp for more details.

If you have single-glazed windows, this may also be part of the problem. Single-glazed windows are a lot colder inside than double-glazed ones, so are likely to attract condensation.

If you do decide to install more insulation or double-glazed windows, this should be balanced with good ventilation in your home, or all the extra energy-saving measures could cause damp problems to reoccur. 

For information about improving your insulation, see our expert guides on:

• loft insulation costs and savings 
• cavity wall insulation costs and savings 
• double glazing costs

5. Make sure your heating is set up sufficiently

Sudden rises and drops in air temperature can exacerbate a condensation problem, as water evaporates and condenses each time your central heating switches on and off. 

You may find that having your heating on a constant low heat is better for damp (and for your air temperature) than having it frequently swing between hot and cold.

If you're going to do this, make sure you're on the best energy deal first. Use our free, independent energy comparison service to compare gas and electricity prices and find the best provider for you.

We've also launched a new home energy planning service to give you the know-how to make the right decisions for improving the energy efficiency of your home according to your means, and for approaching installers with confidence. Follow the link below to find out more:

Make your property more energy efficient

Find out about our free home energy planning service

See more

How to stop condensation on windows

Condensation forming on windows in the winter months is normal and nothing to be alarmed by.

If you implement the tips and recommendations we've covered, you should be able to prevent condensation from forming in the first place, or eliminate the condensation build-up on your windows.

Bedroom windows can be particularly susceptible to condensation, since moisture from your breath and your body heat can accumulate in the room, leading to condensation. So it's important to ventilate your bedroom by having your windows slightly open to clear condensation. 

To prevent condensation from coming back, try spraying a mixture of equal parts water and white vinegar, plus a couple of drops washing-up liquid, onto your windows. The vinegar creates a protective barrier, and soap breaks down the surface tension of the droplets on your window. 

Keeping your heating on a constant, low setting and running a dehumidifier at night will also help keep condensation at bay. 

It's also worth checking your window seals, as if these are old or damaged, moisture can get in and create condensation between the glass panes. Double glazing often comes with a 10 year, 20 year or sometimes lifetime warranty, so if the seals or panes need replacing, check your warranty. 

If don’t know when the windows were installed, you can check with your Local Authority Building Control to find out when the double glazing was installed and if there is a warranty that is still in date. If so, you may be able to get it repaired without cost.