Clearview customers weigh up the pros and cons of double glazing versus secondary glazing. Here’s a brief comparison:
Most double glazing consists of a sealed glazing unit of 2 glass panes usually separated by an air gap of 10-20mm. The air gap helps with thermal insulation, particularly with coated glass and when the air gap is filled with an inert gas. In new buildings, where Building Regulations make double glazing virtually compulsory, double glazing gives energy savings. However, in period property, replacing original windows with double glazed units can create a dramatic, unattractive change in a property’s appearance, because of the need for thicker timber sections and glazing bars, and the flatness of new glass. Double glazing is not normally permitted in listed buildings,
To maintain a period property’s authenticity, fitting secondary glazing and repairing and renovating the original windows rather than replacing them, is the better option. Simply put, double glazing means a loss of historic fabric.
Disposing the original primary window and introducing a bulkier, new double glazing uses more than 3 times the materials compared to a secondary system. Factor in that secondary glazing requires no re-decoration and it’s easy to see why choosing secondary glazing is less damaging to the environment.
Double glazing’s benefits can be overstated compared to other glazing methods. Enhanced energy efficiency and comfort is not just the preserve of double glazing! Significant draught reduction is also a major benefit of secondary glazing. Technical advances and modern production methods make it possible for secondary glazed windows to exceed the performance of double glazed windows.
For noise reduction, double glazing is often no more effective than single glazed units, in fact for traffic noise reduction, they can perform less effectively. The overriding factor in noise reduction is well fitted, draught-proofed windows. Secondary glazing’s larger gap between glass panes is a better noise insulator.
If you are weighing up the benefits of secondary glazing, these pages and downloads may help: