Secondary Dou
There may be many reasons not to replace your current windows with double glazing windows. They may still be in excellent condition, or your house may be listed - in which case, making those changes must be approved. It may simply be that you like the look of your current windows and have no desire to trade them for generically produced and mass marketed sealed unit double glazed windows.
Even if your reason is the expense of replacing all your windows with new, bland energy efficient models, it's hard to deny the appeal of saving money on your energy bills, or living in a warmer, more comfortable house. Secondary glazing is an alternative to wholesale replacement of your existing windows with new sealed unit double glazing windows.
Rather than removing and replacing your existing windows, secondary glazing fits a second 'window' inside your old one. They can be as simple as a heavy sheet of polyplastic that's meant for one season's use, but in most cases, secondary glazing refers to a complete window, glass, frame, locks and all, that's built to fit inside your current windows. While the energy efficiency and heat conductivity aren't quite as effective as replacing the window entirely, the addition of secondary glazing can reduce your heating costs substantially - and make your house warmer and more comfortable.
The optimal air space between panes in standard double glazing is approximately 16mm. Obviously a secondary window fitted inside your house against your existing ones won't have a space so fine. While that actually reduces the heat conservation effect, it has a different effect on sound. Secondary glazing is an extremely efficient and effective way of reducing noise transference from outside. Some of the other advantages of secondary glazing are:
It won't affect the aesthetic of your home's exterior.
This is a major consideration for many, particularly those living in historic homes or who are attempting a period restoration. The interior windows will be invisible from the street, and if they are fitted properly, will not detract from the appearance inside. In fact, well-done secondary glazing with attractive window frames can be a distinct style addition in a room.
Superior sound insulation.
It's not just the double layer of glass that muffles the noise from outside - or for that matter, protects your privacy by keeping indoor noise in. The buffer of air between the windows also reduces the sound waves that get through to disturb your peace.
Secondary glazing is considerably less expensive than replacing the original windows.
Even if you choose high quality interior windows, you'll be saving the labour of removing the existing windows. You also reduce the chance of causing unexpected structural damage to the house when you remove old windows. While rare, it's not unheard of.
Secondary windows can be removed when they're not wanted.
Secondary glazing is fitted into frames that can be opened, slid aside or removed entirely. If you decide at a later date that you don't want the interior windows, they can be easily removed. If you replace your old windows with new ones, you can't change your mind. The only way to undo it is to have new windows made.
About the Author
Matthew Anthony is the author of several home improvement sites including conservatories and greenhouses.