What can I do about condensation between different panes on double glazing

Experts will tell you that fogging or condensation in your double-glazed windows isn’t actually a problem which can be fixed. At least, your window won’t be able to ever be restored back to its original performance level. That doesn’t mean that there aren’t ways of dealing with the problem. You can either replace the glass unit of your window or you can hire a professional who can drill some holes into the outer window pane, clean the window from inside then install a one-way air vent to guard against the problem occurring again in the future.


A thermal or insulated window is also known as a double pane window. It will be made from two glass panels which are sandwiched together over a sealant and spacer to create a gap between each pane which is then filled with a gas such as krypton, argon or regular air. This sealed gap gives the windows their thermal performance. Sometimes, the spacer also contains desiccant materials which help to absorb moisture in the air inside this sealed space. If condensation begins to build up inside an insulated window this usually indicates that the seal has failed between the panels of glass or that the desiccant has become saturated.

If the seal is breached, this allows water vapour and fresh air to get into the window space, resulting in condensation. If condensation appears inside a gas-filled window, this also indicates that the gas has escaped. A thermal window can’t be resealed so, again, there is only one option which is to replace the gas in order to restore optimal thermal performance and to resolve the condensation problem. Most insulated window glazing is able to be replaced as a single unit. This will help you to save the cost of replacing a whole window including its frame.

If you have windows which remain under warranty you should contact the manufacturer or supplier to see if you can get a replacement free of charge. However, if your warranty is no longer valid, you should still discuss the matter with the window manufacturer to talk about the possible replacement options.


If you have thermal windows, the only solution for removing condensation is to remove the moist air which is in between the panes before replacing it with air that is dry. An insulated window repair or restoration company can come out to drill a hole measuring around 3/8” at a bottom and top corner of the window which is affected by the condensation problem. They will then spray liquid solutions on the inner face of the panel via the top hole, sucking them back out via the bottom drilled hole. Once your window is dry and clean, they will seal the holes using small vent plugs to enable water vapour and air to get out of the window cavity without allowing them to get in again.


If you’re experiencing a condensation problem with your windows, you’ll need to decide what kind of remedial action you’re going to take. If you have tempered glass windows, you’ll need to replace them completely, but if restoration is an option for the type of windows you have, you may want to consider this first, especially if you’re keen to save money.

Unfortunately, restoration won’t always work in every case, and it isn’t possible to fully restore any window with a condensation problem to its original level of performance. This means that if you put thermal performance as a top priority you should certainly consider replacement as your best option. This will guarantee that your windows keep your home warm and comfortable all year round.