You may have noticed condensation on your windows and/or doors, maybe that have been newly installed, and wondered what causes it and how it can be stopped. To answer these queries, we have put together this short blog, with clear advice on how to identify which type of condensation is on your windows, and how to effectively treat it.

Is condensation on the outside of windows normal?

If there is condensation on the outer pane of your double-glazed windows, then you have nothing to worry about. As strange as it may sound, condensation on the outside of your windows is proof that your windows are thermally efficient and working properly.

External condensation often occurs in warmer months, usually in the morning, as the cool glass meets the humid air. The outer pane of the double glazing is cool as little/no heat from inside your home has escaped through to warm it (proof that your windows are doing their job). As the day goes on, the glass will be warmed up by the sun, and the condensation will evaporate.

A hand pointing at condensation on the inside of a window.

Is condensation on the inside of windows normal?

Condensation on the inside of windows can occur on single glazed windows, as well as on new windows, with double or triple glazed units. If you have windows with double or triple glazing and are experiencing internal condensation, particularly in the winter months, this will most likely be because the room isn’t adequately ventilated.

The air in our homes always contains water vapour, (produced by washing, cooking, bathing etc), the warmer the air, the more water vapour it can hold. Passed a certain temperature, the air becomes saturated, which when in contact with a surface at a lower temperature than itself (in this case, the glass), the excess water vapour is shed on the surface.

Modern windows are manufactured and installed to minimise air loss, because of this the moisture cannot escape when it hits the glass, so condensation is formed.

As internal condensation is caused by the water vapour content of the air, and the inside room temperature, which can both be controlled, there are many simple things you can do to reduce the condensation.


 How to reduce condensation on the inside of windows

Making very minor changes around the house can make a big difference to the amount of condensation that occurs.

Excess moisture must be removed by ventilating the room. The easiest way to do this is through natural ventilation, which can be provided through open trickle vents on windows, and in the absence of trickle vents, by opening the window slightly, even for a few minutes every day. You should open a window in the bathroom whilst the shower/bath is in use for example, to let the humid air escape outside fast.

You can also improve ventilation in your home by:

  • Installing a positive input ventilation (PIV) unit. It works by extracting the humid air from the inside the house and draws in the dry air from the outside, which helps to maintain the humidity balance.
  • Installing an extractor fan. These are used mostly in bathrooms and kitchens to reduce the excess moisture produced when showering and cooking.
  • Using a dehumidifier. The excess moisture from the air is extracted and collected in a tank, which is then disposed.

Double glazed casement windows

Is condensation in between windows normal?

If there is condensation within the sealed double-glazed unit, it means that the unit has failed, and can only be fixed by replacement. If your windows have been recently installed and are still under guarantee, the replacement should be covered with the installer, however if the windows are old, you will need to contact a professional to replace the glass unit.

If your window has a failed unit and is more than 10-15 years old, it will be more cost effective for you to replace the whole window as opposed to the glass unit only.


Quality Window and Door Installers in Swindon

Need a reliable double-glazing installer in the Wiltshire area? Look no further than Emerald Windows and Doors, a family run business, which have been transforming homes to the highest standards for the last two decades!

Get in contact  for a free quote by sending us an email or fill out our online contact form. Whether you’re looking for a new front door, a beautiful conservatory or a houseful of replacement windows we offer a plethora of high standard home improvement products. We can offer you a free quotation which covers our supply, fit and aftercare service.

You can also visit our showroom in Swindon where you can explore our vast variety of products including; Flush sash windows, tilt & turn windows, uPVC windows, Patio door, Composite doors, Stable doors, French doors and Conservatories– just to name a few!

For your next double glazing home improvement project you can rely on our team that have years of experience working in Swindon and the local area including: Bristol, Oxfordshire, Chippenham, Cirencester, Marlborough, Reading and Melksham.

serving homes across wiltshire

Related blogs:

Can you fit trickle vents to existing windows?

The benefits of triple glazed windows.

Do new windows help sell a house?




Areas we serve

Swindon-based family run double glazing installers

With a head office in Swindon, a short trip from the motorway, we are ideally located to offer our services across Wiltshire, Reading, Bath, Bristol, Marlborough, Berkshire, Gloucestershire, Oxfordshire, and other surrounding locations.

Emerald provide and install home improvements in all materials – uPVC, aluminium and traditional timber. No matter what material you choose, you can be sure we’ll provide you consistent quality – our work is always finished to the highest standards, whether you’re installing 2 windows or 20!

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