What Is Secondary Glazing?

Secondary glazing involves installing a pane of glass and frame to existing windows. Unlike double glazing, which would remove a single glazed window and replace it, secondary glazing is added to the existing window.

The purpose of installing secondary glazing is to offer energy insulation and soundproofing to your windows. It is a cheaper solution to double glazing and is a good option if you cannot replace existing windows due to living in period or listed properties.

The exact cost of secondary glazing will depend on several factors like the number of windows you need to install and the type of window you have. It will also depend on whether your motivation is mainly for noise or draft proofing. Noise reduction proofing requires a particular type of glass which is slightly more expensive.

The following prices are examples costs for secondary glazing for two window types:

Type of glazing	Cost of noise reduction secondary glazing	Cost of draft reduction secondary glazing
Sash windows	£1057 + VAT	£870 + VAT
Horizontal sliding windows	£894 + VAT	£685 + VAT

Secondary Glazing Costs vs Double Glazing Costs

As you would expect, double glazing costs more than secondary glazing, as it requires refitting existing windows. If you are bent on saving and have some room to play with, secondary glazing may be your best bet.

How do double and secondary glazing costs compare? If you’re on a budget, secondary glazing can cost up to half the price of double glazing. Of course, prices will vary, depending on whether you’d like sash or horizontal sliding windows, which are cheaper.

Type of glazing	Cost of noise reduction secondary glazing	Cost of draft reduction secondary glazing
Sash windows	£1057 + VAT	£870 + VAT
Horizontal sliding windows	£894 + VAT	£685 + VAT

Cheap Secondary Glazing

How can I save on my secondary glazing? You won’t be able to control the style of your windows. But you can pick cheaper frame materials: the lowest cost option is uPVC, with aluminium and wood at the upper end of the scale. You may also want to look at different types of glass – generally speaking, the thicker, the pricier.

The cheapest type of secondary glazing is draft reducing glass, with prices between £685 and £870. Secondary glazing which reduces noise needs more substance, and costs between £895 and £1,057 per pane.

Should You Install Secondary Glazing?

There are 5 factors to consider when choosing whether to install secondary glazing:

1. You live in a period or grade I or II listed building where you are not permitted to install double glazing.
2. You cannot get planning permission for double glazing installation. Secondary glazing installation does not require planning permission, and can easily be installed by homeowners themselves.
3. You want to retain your original windows, and do not want to alter the external look of your building with modern-looking double glazing. Secondary glazing solutions are fit on the interior of the existing window and can come in discreet styles and means of opening for easy access.
4. You are on a budget. Secondary glazing is considerably less expensive to install than double glazing. This would suit homeowners on a smaller budget who want to conserve energy but require a cheaper solution. You can also reduce costs by fitting the secondary glazing yourself and eliminating installation costs.
5. You live on a busy road or in a built-up area. Secondary glazing is more effective at reducing noise pollution than double glazing. This is because there is a larger space between the existing window and the secondary glazing which is better at lowering sound levels than the two sealed panes within double glazing which are closer together.