can the glass be resealed? or do i have to replace the double glazed unit

Alan, May 2008

how do i remove failed double glazed unit from an everest aluminium window

russ, November 2013

mist forms as fluctuations in air pressure and temperature cause damp air to enter the gap through
a break in the seal - you can use this bellows effect
to remove the moisture -
wait for a sunny day with low humidity and the sun
shining through the window

get some sheets of black plastic eg rubbish bags etc and spray
them with water to stick on the glass inside the room
covering the whole pane. after say a half hour or so
the air in the gap will heat up picking up moisture
(hot air holds more water) and expand with some escaping the way it got in. next remove the plastic
for half hour
the internal pressure will drop sucking in drier air.
repeat the heat/cool cycle maybe 10 time or more

will, August 2011

Hi, Have been reading this site, and others, with interest as we have several windows that are misted (dodgy fitter that was recommended by a reputable builder- since gone bust !!!). We had a ten year guarantee when all the original units were installed, when we went back after only 5 years we were told the glass was not covered. We then rang trading standards who confirmed that the 10 year gaurantee/warrantys that are provided are only for the Upvc surrounds, locks and hinges, glass is not covered and there is nothing anyone can do. My point being, after all this waffle, is that several people on several sites recommend to get replacement units as you get 5 or 10 year guarantees, I would question this to make sure..

jeff15, June 2011

Hi, thank you for your post Alex. I live in Tettenhall Wolverhampton so i took your advice and rang Wolverhampton Window Services, and i must say i was VERY impressed with the service i received. I rang their freephone number at 9pm after finishing work, to my surprise someone answered, and made an appointment to measure the misted window the next day.
At 8am the next morning a well mannered and polite gentleman arrives to measure the window. He takes the measurements and worked out the price to which i agreed, he sent an email from his mobile phone and to my astonishment said, "i'll be back in 40 minutes, just going to pick up your new unit..." i couldn't believe it, he returned and fitted the new glass ever in less than an hour and he cleaned up after himself too.
I was so amazed at how fast this window was made and fitted and to imagine i had left it for years thinking nothing could be done about it. I honestly would say this has to be the best service i've received ever and would recommend anyone with misted windows or any other type of double glazing problems to ring them on 0808 225 1500 or visit their website at www.wolverhamptonwindowservices.co.uk .

Jackie, May 2011

www.shepwayglass.co.uk, sealed units changed from £62

jordan, April 2011

where can you buy the vents/valves and how much do they cost?

DaveM, March 2011

Some double-glazed units are filled with Argon, but they're ones that have a very large gap between the panes (say 16mm or 20mm). If it's less, it will be filled with air (certainly not a vaccuum).

Alan, March 2011

misted units can be repaired but dont have the same guarantee as a new one ,you are best replacing the failed unit with a new one at least you get another 10 year guarantee

roy double glazing repairs, February 2011

get new units!!!!!!!!!!!!!!!!!!!

debbie, January 2011

new units carry a guarantee and is the only way to cure the problem as stated before drilling the glass will weaken the surrounding area and does anybody know the difference in price beetween fitting a valve and replacing a unit is it worth drilling if there is only a few pounds difference????

mark www.window-tec.co.uk, January 2011

A number of answers have said that the units are inert gas or vacuum filled. They certainly are not if they have condensation in them!

Engineer, January 2011

Only way to put an end to misted windows is to have the units replaced. This way you also get a 10 year peace of mind Guarantee the misting won't come back. Measure the height and width of the double glazed unit that has misted (don't worry if its not accurate, the engineer will come out and re-measure anyway) call Wolverhampton Window Services FREE on 0808 225 1500, (they cover the whole of West Midlands). The call is free and you will receive an instant quote over the phone in less than 2 minutes.

Alex, January 2011

Has anyone tried these people?

www.misty-windows.co.uk/solution.htm

Do you reckon it would work?

DaveJ, October 2010

It is well known that if you drill holes in annealed glass or wall tiles, the area around the hole is weakened.
also a friend of mine had four units fitted with two vents in each panel. what an eyesore!
ps. she had them changed for new ones.

frank, September 2010

Most of the answers are nonsense. A double glazed unit is either a vacuum or filled with an inert gas. Drilling holes into it will not give you your required U value of the Unit.

You will waste heat as the unit is no longer as efficient as it was when new. There is only ONE answer to a misted unit REPLACE it.

MovieMakerNow, September 2010

I have been a Glazier for 40 years. The problem with drilling holes in glass is that it weakens the glass around the hole and when it is exposed to extreme weather conditions ( cold /hot ) the glass will crack.
My advice is to have a new double glazed unit it is cheaper in the long run.

andy, June 2010

"sadly you cant repair a misted double glazed unit and will need to replace with a new 1"
LOL at the last comment, which has been proved WRONG by all the previous ones! Where do I sign up Shaun? You wouldn't happen to be completely biased by any chance, would you?

John Rodford, April 2010

1. Dead easy !!! Drill 2 holes at each diagonal corner, in the spacer seal via the window frame from the side of window and allow to dry, then plug it and forget it for 2-3 yrs, then repeat.
2. Very Easy !! You can remove the unit and cut one of the glass out using a sharp blade, then re fit it as a single unit.
3. Easy ! You can do above, drill a hole at a corner and remove the dry crystalls from the seal spacer, heat them on a pan to dry them, refill the seal, plug using silicone filler, clean insides of glass panes, seal glass with silicone to the spacer, allow to set for hour, gently fit to the frame, making sure u sit it on plastic packing.
4. Do nothing or get ripped off by the installer.

Kam, March 2010

once a double glazed unit faileds the water leaves a water mark. so best to buy new

Emmett, March 2010

This may help clear the condensation but if you let air circulate in a sealed unit it will no longer be a sealed unit and will no longer be serving the purpose it was put there for. If you replace your old inefficient sealed unit it will cost abit more first off, but with new low emission sealed units they are proven to be much more efficient and will help keep your fuel bills down and help save the environment.

kevin, January 2010

I can change misted units, Just £40 per sqm

pvc-u-fix, January 2010

Opening windows only:

1] Open window.

2] bore small hole in side near bottom at centre of plastic/wooden window frame [to get into gap between the 2 panels through aluminium joint.

3] Heat window in situ with hair drier on outside of glass until all moisture evaporates.

4] Make a funnel with thin card and push into hole through frame and glass joint with the aid of a small round file or similar roughened knitting needle, Remove file or needle.

5] Quickly pour in ground-up silica gel crystalls and push silicone grease into hole in frame until you can see a dollop of it in sealant joint.

6] Seal bore hole in plastic/wooden frame with any suitable waterproof sealant.

7] Go to pub or go shopping....

plughole, December 2009

My double glazing window handle is very stiff. Please how do i release it.

chuks, November 2009

I have a misted sash window which opens. So I open it and then drill a hole in the plastic between the panes, right? And the hole should be near the top of the unit at the side, is that right?

Bryan, March 2009

Misted double glazed units can be repaired by fitting 3.5 mm vents. This process is much cheaper than replacing units and is a permanent repair. A local company to us, carry out the work and offer a 20 year guarantee. The valves could be fitted during manufacture, but that would kill off the replacement business.

Mr Save Some Money, March 2009

I had the common problem of misting between the panes of double-glazing, and a local firm solved the problem. They drilled a small hole in the top and in the bottom of the external panes and fitted small valves to allow the moisture to evaporate away. After a few days the moisture had gone.

Caravan windows are made of some sort of plastic and are double glazed. Each unit is fitted with a similar valve (internally) and misting never occurs.

If a DIY-er could obtain such valves and inert them in the inside pane of the failing unit, it would be a "permanent" repair, preferable probably to the silicon blob. The glass can be drilled using a diamond tipped bit, say 1/8", 3mm.

If the fault lies in an opening light, it is of course much easier to drill a small hole through the woodwork.

GJK, August 2008

Take the sealed unit out of the frame.
Drill a small hole in the seal between the 2 sheets of glass.
Stick the unit on a radiator on at full blast with the small hole at the bottom, allowing any moisture to escape.
Once the moisture is gone, seal the hole with a blob of silicon sealant (not just any sealant - must be silicon).
Et voila - it won't last for ever, but it should more than do for a couple of years...

Windy Licker, June 2008

I also have several double glazed units that are misted. It is a common failure especially on units exposed on the sunny side of a property. There are companies that provide a repair service. They nearly all seem to work on the principle of providing a small valve or vent which opens when the unit heats due to action of the temp. changes, the warm moist air from inside the unit expands and some of the moisture is expelled, this process quickly dries out the interior. The main difficulty for us DIYers is getting hold of the valves/vents and secondly drilling the small holes in glass which is often toughend on larger panes. I propose to make a special bit with grinding paste to 'wear' a hole through the glass, a technique I have used succesfully on glass/ceramic before. I would suggest that it may not be in the interest of some people to to agree with my solution as it might interfere with their commercial interest ;-) Pete.

Pete Stamp, June 2008

sadly you cant repair a misted double glazed unit and will need to replace with a new 1

shaun www.sdwupvcrepair.co.uk, May 2008