Often a question asked by a waiter when ordering water in a foreign restaurant but some customers are asking the same question here in the UK, concerning double glazed sealed units.
When sealed units were simple (air filled) the only issue was the amount of water vapour trapped between the two sheets of glass, when the sealed unit was manufactured. Silica gel crystals provided a simple solution, as they would suck out any moisture so trapped for the life of the sealed units.
The only reason sealed units get misty between the sheets of glass is because the perimeter seal has failed, allowing more air and moisture to enter the sealed unit (more than the silica gel crystals can cope with) so moisture forms on the inside face of the glass. Sometimes (like the above pictures shows) the crystals fall out of the spacer bar!
With modern sealed units gas is often used but how do you tell if your new windows have got the argon or krypton gas that you have bought?
Well it is virtually impossible for retail customers to establish, however there are spark guns that can fire electrodes that measure the resistance of the gas, however these are expensive and not entirely accurate. frankly the best solution is to go to a reputable company. Any decent company just doesn’t cheat its customers, its part of the process, it get done, and if accredited by a third party, BSI, BBA etc then they check the records to show the purchases of gas.
I guess however that if you choose to pay the cheapest price for double glazing, then it is an obvious place for a company to cut back on, sell it a gas filled and dont bother doing it!
Moral of the story, be happy that the specification you get shown (and agree to), gets written into the contract you sign for. Make sure you know the company has the third party accreditations it claims, so that you have confidence you should get what you expect, or just buy the cheapest of cheap but don’t be surprised that its not quiet what you thought you had ordered!
Beware, triple glazing has many benefits but one significant drawback is that e