Some of you might be wondering can I double glaze my original sash windows? The answer is yes as long as they are thicker than 37mm. This is the standard bare minimum that we can insert a standard double glazed unit. It ‘s important to note that we do not use slim lite as it is not very good for sash window sound proofing. While they do help considerably with heat retention and they are good for noise. The small air gap means that they are far inferior to a quality sealed unit with a larger spacer bar. An example is that an air gap maybe only 3mm on a slim lite unit. This is simply not enough to make a considerable difference when we consider sound about heat insulation. The normal unit we will install is 8mm and this is some 250% wider than the slim lite unit. Although it’s not 250% more efficient it is noticeable at a practical level and of course a standard unit is actually cheaper than a slim lite unit. The installation of a slim lite unit is slightly easier into an original sash window than traditional quality double glazed unit however the extra effort is well worth while. The amount of work isn’t that considerable when you think about it. After all we still need to remove the old original glazing in both cases and this means hacking the putty away to make room for the new unit. The only difference is that a standard unit then required a large rebate cut which can actually improve the aesthetics because fresh timber is removed and this leaves a nice clean edge.
This presents a separate issue that the sash could be structurally weakened, and in which case your only option will be slim lite but as long as your sash is larger than 37mm there is every chance that this process will be viable for you. Normally the double glazing of original sash windows in done in conjunction with a quality sash window draught proofing system. The draught proofing system creates the tight seals around the edges of the frames whilst the double glazed unit handles the noise transfer. Combined they workout to be a super efficient an inexpensive way of protecting the home against sound pollution. The two services combined on an original sash window may cost as little as £600 per window .This is an incredible saving over the entire replacement which may be in the region of four times this cost. A staggering saving for the same level of sound proofing then. Most homes in London are having their windows double glazed as it also increases security as well as promotes home valuations, not only that, it makes the home more sellable when it is eco friendly. I would highly recommend double glazing of original sash windows in London and I am sure that no better value for money can be found elsewhere. If you think we’ve missed any information or would like us to take a look at your windows then feel free to get in touch as we welcome all enquiries from one window to a whole house.