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How Much Condensation Does a Person Produce?

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How Much Condensation Does a Person Produce?

By Ruth MacEachern

Product Manager

Jul 29, 2022

If you’ve ever woken up on a cool morning and seen droplets of water streaming down your windows, you have experienced condensation.  In our homes, condensation is caused by moisture being released from humid air when it meets a cool surface.  The main source of domestic condensation is people, but did you ever wonder how much water vapour an average person releases into the air each day?

What Activities Cause Condensation?

Anything that releases some water vapour into the air will increase humidity, and eventually contribute to condensation.  Some of the most common contributors are:

  • Boiling a kettle
  • Cooking
  • Using a Washing machine or dishwasher
  • Drying clothes on a radiator or an indoor tumble dryer
  • Bathing or showering
  • Breathing

Here is how much water vapour is created by each of these activities

Boiling a Kettle

Kettles contain most of the steam produced when boiling water, but some will be lost.  Typically, during the two minutes or so it takes to boil half a litre of water to make two cups of coffee, about 10g of water (2%) is lost as steam.  If you make 8 cups of coffee or tea during the day, this releases about 80g of water into the air.

Cooking on the hob

If you don’t use a pan lid when boiling food on the hob, the amount of water lost as steam can be much higher than with a kettle or a lidded pan.  If you are cooking pasta on the stove for 10 minutes in 2 litres of water, you might create as much as 100g of water vapour.  Leaving a lid on the pan will reduce this considerably and help to get the water up to temperature more quickly, saving you energy.

Washing Machines and Dishwashers

The amount of water vapour released by a washing machine depends on the temperature of the wash, and where the water is drained after use.  Cooler washes at 30C will release far less water vapour than hot washes, and use less energy, however an average wash could still release between 25-50g of water vapour. 

Dishwashers usually work at a much hotter temperature than washing machines, which means that they create a lot of steam, but they are sealed, so they don’t normally create much water vapour in use.  If you open a dishwasher immediately after the cycle has finished, then you will release a large amount of water vapour into the air quickly, however leaving the dishwasher to cool first will allow the steam to condense safely into the machine and drain away.  The cloud of steam released when a dishwasher is opened can contain as much as 20g of water which will increase humidity in a small kitchen considerably.

Drying Clothes or towels on a Radiator

Wet clothes are much heavier than dry, and all the difference in weight is the amount of water that is left in the fabric during washing.  A bath towel can hold as much as a kilogram of water, and if this is dried on a radiator it can be a major contributor to household moisture levels.

Of course, drying clothes on a radiator isn’t just a major contributor to condensation.  It also makes your radiators less efficient at heating your home and allows a type of fungus called aspergillus to grow which can be harmful to the health of your household.

A tumble dryer is a more effective way to dry clothes, but it too will release a large amount of water vapour when in use.  If the dryer is properly ventilated, then most of the steam will be released outside, but opening the door in use can cause a great deal of steam to form indoors.

Bathing or Showering

Taking a bath or shower releases a staggering amount of water into the air of your home.  On average, 1.7 kilos of water are released when bathing or showering, which is why bathroom extractor fans are so important.


Every day an average person breathes in around 14,000 litres of air, and with every breath, we release a small amount of water vapour.  Over a day, this builds up to around 400g of water vapour created.  People who are active will breathe out more due to higher internal temperatures.  During the night, because we normally sleep with doors and windows closed, the concentration of water vapour in the air is higher, and due to colder temperatures outside, we are more likely to see condensation form on windows as a result.

The Total Water Vapour Created by a Person

If a person does the following over the course of a day:

  • Drinks 8 Cups of coffee or tea
  • Boils one pan of water for 10 minutes
  • Takes a shower
  • Uses the dishwasher
  • Washes and dries 2KG of clothing
  • Breathes normally

They will Contribute around 2.5KG of water – the equivalent of 10 glasses of water – into the air.  Without good ventilation in the home, this will settle on windows, walls, and other cool surfaces as condensation, and can quickly lead to damp and mould.

Read More: 14 Ways to Reduce COndensation in Your Home >

Stop Condensation for Good

Good ventilation is the best way of preventing condensation from being a problem in your home.  Enter your postcode into the form below to find your local EnviroVent specialist.  We can arrange a free home survey that will identify the causes of condensation in your property and provide you with advice to help stop permanently.


Need help with condensation, mould or damp problems?

One of our local experts will contact you to learn more about your problems, offer free expert advice and make recommendations for a permanent solution.

During the free survey we will

  • check Assess any condensation, damp or mould problems in your property
  • check Take readings of the relative humidity levels
  • check Identify any underlying problems and make recommendations for a permanent solution

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