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How to remove condensation inside a car

Got a problem with damp and condensation inside your car? Our handy guide will tell you what you need to know, including what can cause it, what to do to get rid of it and how to prevent it happening again.

Got a problem with damp and condensation inside your car? Our handy guide will tell you what you need to know, including what can cause it, what to do to get rid of it and how to prevent it happening again.

Written by
Rory Reid
Car and technology expert
Last Updated
5 JULY 2023
7 min read
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What causes condensation in my car?

Condensation is caused when the warm air from inside your car hits glass cooled from the outside, which condenses to create moisture.

Steam can also cause condensation in cars. If there’s something wet inside your car and the sun then heats the interior, the rising steam collects on the surfaces as moisture.

There are several other sources of moisture that could increase the humidity in your car and lead to condensation, including:

  • Breath from passengers in cold weather
  • Wet items like coats, clothing, shoes and umbrellas
  • Leaks from doors, windows, the sunroof or vents
  • Steam from hot drinks and food
  • Coolant leaks.

How to stop condensation in my car?

You’ll likely experience condensation inside your car at some point when you drive, but there are a few simple steps you can take to help keep moisture out of your vehicle.

Don’t leave wet items in your car

When it’s time to park up at the end of the day, take any damp items with you when you leave the car. That could mean your umbrella or raincoat, your gym kit or the dog blanket. All of these damp items could cause humidity in your car, which can lead to condensation.

Keep the windows open when you have hot food or drinks

Sometimes it makes sense to eat inside your car, but the steam coming off your morning coffee and lunchtime pasty can humidify your car. If you’re not able to keep the windows open while you eat or drink, turn the air conditioning on to suck out that extra moisture – and remember to throw away any rubbish away as soon as possible.

Keep your car covered overnight

If you keep your car in a garage, a lightweight, breathable cover could help keep condensation forming inside your car when parked. If you have a serious problem, you could use a dehumidifier or a low-powered heater to keep the air dry.

If you’re storing a car for long periods, remember to take it for a drive regularly. This will keep everything ticking over and give it a blast of fresh air, as well as stopping your car battery from going flat.

For more on keeping your car in a garage and the possible impact on your car insurance, see our overnight parking guide.

Use your air con and windows

It sounds simple, but keeping the windows ajar on hot days and closing them on wet days will help keep your car damp free.

In the winter, you could turn on your air conditioning – even while the heating is on. The AC system draws the air from the inside of your car through an evaporator, which condenses moisture and drains it outside of the car.

Keep your car windows clean

Condensation sticks to dirt and grime. To stop condensation forming on your car windows overnight, keep the inside of your windscreen and windows sparkly and clean.

Watch out for leaks

If you’re consistently noticing a lot of moisture build up in your car, you might have a leak. Leaks in the door seals, the boot or the sunroof could allow rainwater to seep in and cause areas of damp. The heater matrix (the mini radiator that warms the inside of the car by taking the heat from the car's cooling system) is another common culprit when it comes to leaks. If you do suspect a leak, it’s worth speaking to a professional to see what they can do to fix it.

How to clear away condensation from your car windscreen and other windows

If you get in the car in the morning to find your windows all fogged up, it’s vital that you clear away the condensation before you drive. If you can’t see out of your windscreen properly, you can’t drive safely – or legally.

Here’s how to get your windscreen cleared of condensation so you can get on your way:

  1. Turn on the heater but start off on a cool setting, using the windscreen option if you have one.
  2. Switch on your air conditioning to get the air circulating. If you don’t have air con, open the windows.
  3. Gradually turn up the heater as the air in the condensation begins to clear.
  4. If your car has one, turn on the windscreen and rear window heater or demister to help speed it along.

How to dehumidify a car and remove damp

If a lot of moisture has built up inside your car, then you’ll need to dry it out to avoid problems with condensation and mould in the future. Here are some tips to dehumidify your car:

Air out your vehicle

The best way to remove damp and prevent mould in your car is to air it out. If it’s a mild day with no chance of rain, open the windows and doors for as long as you can – if it’s safe to do so – but don’t leave your vehicle unattended.

If moisture appears while you’re driving, crack a window open if it’s dry outside or turn on the air conditioning if it’s raining.

Remove excess moisture from your car

Remove any excess moisture from surfaces in your car with a dry cloth. You might also want to try using a fan or hairdryer to dry the upholstery or particularly damp surfaces.

How to get rid of mould in your car

Getting rid of mould in your car is not a pleasant job, but it’s necessary. Not only does it look and smell horrible, but it could also have negative effects on your health.

Luckily, you won’t need any specialist tools to clear out the mould from your car – just a few household items and some elbow grease. It might be a good idea to wear rubber gloves and a mask while doing it to make sure you don’t breathe in any mould spores you disturb. Here’s what to do:

  1. Start by cleaning out your car. Remove any rubbish and belongings from the inside and throw away anything mouldy.
  2. Vacuum the carpets, car seats and any other upholstery to remove any mould spores.
  3. Fill a spray bottle with a mix of distilled white vinegar and water, with a ratio of eight parts vinegar to two parts water. White vinegar removes mould and could prevent it from coming back. Alternatively, you could buy a specialist cleaning product.
  4. Spray the vinegar solution onto any mouldy surfaces or upholstery. Saturate these areas, using a scrub brush to work the solution in. You may want to test a small amount of the solution first on an area that’s generally out of sight.
  5. Air out your car to help remove the vinegar smell. Once it’s dry you can apply baking powder to any areas you’ve treated and then hoover it up.

What causes mould in cars?

Damp and a lack of air circulation causes mould in cars. To prevent it recurring in the future, follow our tips above on how to prevent condensation from forming and dehumidify your car.

If a larger problem like a leak is causing damp in your car, you’ll need to fix the leak to prevent the mould from returning in the future.

Does having damp in my car affect my insurance?

If your car isn't deemed roadworthy because of damp, leaky parts, mould and water, this could invalidate your insurance policy and lead to expensive vehicle repairs.

Check out the common issues that lead to car breakdowns.

Frequently asked questions

Why is my car wet inside?

There are several reasons why your car may be wet inside. Maybe you left the window cracked open and it started raining, the sunroof has leaked or a door seal has gone. Maybe one of the kids spilt something in the backseat and didn’t tell you.

Condensation is another common cause of damp inside a car. This happens when warm humid air inside your car meets the cold of the windows and windscreen and condenses into water droplets.

What products can I buy to get rid of damp in my car?

You can buy dehumidifiers, which are bags filled with silica gel that sit on your dashboard and absorb moisture. These packs can be microwaved afterwards to remove the moisture, allowing them to be reused.

Some people also swear that filling a pair of tights with cat litter will do the same job. We can’t guarantee it works, but it might be worth a try.

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Rory Reid - car and technology expert

Rory Reid is a car and technology expert. He serves as the main presenter on Auto Trader’s YouTube channel and was previously a host on BBC Top Gear and its sister show Extra Gear. He is also a presenter on Fifth Gear. Previously, he hosted Sky TV’s Gadget Geeks, CNET’s Car Tech channel, BBC Radio 5 Live’s Saturday Edition and on the YouTube channel Fast, Furious & Funny.

Learn more about Rory

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