Replacing double-glazed sealed units in a large picture window

Thanks to some helpful advice on the uk.d-i-y newsgroup and the double-glazing-web.info forums, I realised that my "steamed up" picture window in my bedroom didn't need to be completely replaced. Instead, I could apparently get just the sealed units replaced. I looked up "Double Glazing Repairs" in the Yellow Pages and rang about five places. Three got back to me and two came and measured up for a quote. One incorrectly stated that I didn't need toughened glass, so I went with the other quote.

Here is a picture of the window taken the evening before it was replaced:
You can see that the window had actually gone beyond "steamed up" - there was enough moisture inside the unit that it had started to dribble down the inside panes. When it had just been condensation, the unit would occasionally clear again if the weather conditions were right. At this stage the view from the window was permanently obscured.

Here is a picture of the window during the replacement, after the sealed unit had been removed:
The window is externally beaded, and the rubber strips you can see on the window sill are the internal beads. These needed to be removed so that the window could be shifted away from the external bead (rubber attached to UPVC), which could then be unclipped from the frame. Once the unit was out, the drainage was checked and the spacers replaced. The spacers are like little plastic bridges which sit in the channel under the sealed unit. They allow any water which gets past the bead to flow along the channel and out through drainage holes.

Here is the window with the new sealed unit fitted and cleaned:
The installation procedure was basically the reverse of the removal procedure, as the Haynes manual would say. If you look closely in the top-right hand corner of the window you can see the Pilkington logo, but it doesn't spoil my view! The whole procedure took about an hour.

Could I DIY?
I certainly wouldn't have done this job myself on this occasion, for three main reasons:
    1. I hadn't seen it done before
    2. It was at height with a very large sealed unit
    3. I had no experience of sourcing double-glazed units
I would consider "doing it myself" on smaller windows in the future.

I should say, however, that I thought the service supplied by the "window surgeon" was very good value - I paid Ł145 which included having the old unit taken away. The sealed unit was about 1.7m wide by 1m tall and I am based in the south-west.

I hope the information on this page is useful to people who have "steamed-up" windows, or who are just considering replacing their sealed units for other reasons. If you want to email me, you can use the form here.

Al Reynolds