People are often surprised to see external condensation on double glazed windows, expecting the cause is a fault with the unit.  Condensation on the outside of windows can be particularly noticeable during the Autumnal months. External condensation may occur on the latest energy efficient double glazed windows and demonstrates that the windows are doing a fine job of keeping heat in the building.

Many homeowners may be concerned at this “strange” phenomenon however this occurrence actually demonstrates the effectiveness of the glazing. Previously, where condensation occurred internally the “cold spot” of the sealed unit is now external and proves that the heat is being retained rather than lost through the double glazed sealed unit. The condensation will naturally evaporate once the atmosphere warms up.

The phenomenon is a natural and predictable event caused by the outer pane of the glazing being colder than the glass that it replaced. With single glazing and older style double glazing a larger proportion of heat was lost to the outside through the glass. With modern low E Glass products more of the heat is kept inside and the outer pane is not heated as much.

Moisture condenses out of the air onto a cold surface that is said to be below the dew point. The dew point varies with the air temperature and the amount of moisture it contains. In spring and autumn in particular the glass temperature can fall to a low level during the night and the dew point can be comparatively high in these seasons. The glass is more often likely to be below the dew point in these conditions and the moisture condenses onto the surface.

So there is nothing to worry about if you see external condensation on your double glazed windows.  External condensation forms on the exterior surface of the outer pane of glass when its surface temperature drops below the outdoor dew point temperature – increasingly likely on an Autumn or Winter morning, hence why it is only in these current climatic conditions that it occurs.

Internal condensation on windows.

Did you know four people living in a 3 bedroom property would create 112 pints of moisture a week from just breathing, cooking, showering and boiling the kettle?

If you constantly have to wipe condensation off your windows and have a dehumidifier running for lengthy periods of time then you may want to think about whole house ventilation as a permanent solution to condensation and to improve the air quality indoors for your tenants or family.

If you are looking for a short term fix rather than a permanent solution then here are our suggestions to reduce the condensation levels in your property:

Tip 1:

If you have a washing machine or tumble dryer in your property, ensure that it is vented correctly. From just one load of washing two litres of water is emitted into the air.

Tip 2:

Where possible, try to dry your clothes outdoors to prevent excess moisture from building up in your property. If you are unable to dry your clothes outdoor then keep them in a bathroom with the door closed and windows open until the clothes are fully dry.

Tip 3:

When cooking food, boiling the kettle or taking a shower, ensure that your kitchen or bathroom door is kept closed to prevent the moisture in the air from going into colder rooms which will cause condensation to form if it touches a cold surface.

Tip 4:

When cooking ensure that you cover your pans with a lid to reduce moisture being created from the water boiling. Also, ensure you are using an extractor hood if you have one above the cooker or an extract fan if you have one installed, these are designed to help reduce moisture created when cooking. Remember, don’t turn off your extractor fan as soon as you finish cooking as the moisture can still be in the air even when you have finished, instead leave it on afterwards for 10-15 minutes to help to clear the humid air. Another option is to purchase an extractor fan with intelligent humidity sensors which speed up when you start boiling water and slow down once humidity levels have returned to normal.

Tip 5:

Similar to when cooking in the kitchen, when you are taking a shower or having a bath ensure that you turn on your extractor fan to remove the steam and moisture that is created when running warm water in a cold environment. This will help reduce the amount of condensation that appears on your bathroom windows and walls.

Tip 6:

Portable gas bottles and paraffin heaters produce a lot of moisture, along with a lot of toxic fumes. Not only is this form of heat causing excess condensation in your property, it is also a health and safety hazard which is stated in most tenancy agreements as not allowed in rented flats.

Tip 7:

Many families have house pets and plants which produce a lot of moisture. Make sure you cover up your aquarium or fish tanks to prevent excess moisture. If damp patches start to appear on your walls or you start to notice more surface condensation on your windows and walls near to your house plants then look to move them outdoors.

Tip 8:

If you don’t have an extractor fan in your bathroom or kitchen then make sure that you wipe down any cold surfaces when you have been cooking or taking a shower to remove any moisture that may have settled on the surface. This excess moisture in the air sits on the surface and will quickly turn to mould if left untreated.

Tip 9:

Do not overfill your wardrobes or kitchen cupboards. A lack of ventilation and air moisture trapped in warm overfilled cupboards can become a breeding ground for mould as the air is not able to circulate freely inside. You might notice a musty smell or clothes might have a damp feeling to them which is a sure sign that the cupboard is overfilled.

Tip 10:

For the same reason as above, make sure that your furniture is at least 50mm away from the surrounding walls so that air can circulate around the property. Try to ensure that your wardrobes are placed against internal walls in your bedroom which will be less cold than external walls and less likely to cause damp and mould problems.

Tip 11:

Ensuring an adequate amount of heating in your property will improve the internal temperature of surfaces in the house and reduce the likelihood of condensation. Also, make sure your home is energy efficient by ensuring you have insulated walls and double glazed windows installed so the heat doesn't escape from the property.

Tip 12:

If you use a room on a regular basis, such as a living room and the weather is not cold outside, open a window slightly to improve the ventilation in the room. Breathing is a major cause of condensation so this will help to improve the ventilation in your property.

Tip 13:

Double glazing, loft insulation and draft proofing will help to reduce the amount of heat that is lost from a property. Installing insulation will help to keep the temperature of the surfaces inside your property at a higher level.

Tip 14:

Adequate ventilation is essential to allow the moisture to escape from a property before it turns into condensation. Installing an energy-efficient extractor fan in the kitchen and bathroom can improve the humidity levels and prevent condensation.

If you are not sure if the problem is condensation or whether it could be rising damp or due to a leak from the roof or guttering or from failed cavity wall insulation then get in touch to request a free home survey and our surveyor will visit your property at a time to suit you and check whether the problem in your home is due to condensation.

Something like our Drimaster PIV Unit could be exactly what you require.  https://www.carbon-catch.com/drimaster-positive-input-ventilation

If you require some help in eradicating damp problems and condensation in your home then contact Carbon Catch today and we can arrange for a free survey to see what can be done to help.