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Alternatives to double glazing





Note: payback is 20+ years

If you can’t afford double glazing here are a few other ideas to help prevent warm air escaping from your home through windows.

​Secondary glazing

Money saving tips

If you can’t install double glazing – for example, if you live in a conservation area, period property, or listed building – you can install secondary glazing which can reduce heat loss from a window.

Secondary glazing is a secondary pane of glass and frame which can be fitted inside the existing window reveal. This won’t be as well sealed as a double-glazing unit, but will be much cheaper to fit, and will still save energy. Low emissivity glass will also improve the performance of your secondary glazing.

Styles and types of secondary glazing

Vertical sliding windows:

Vertical sliders are the most popular type of secondary glazing as they are easy to use and provide a good level of insulation.

Horizontal sliding windows:

When it comes to secondary glazing style, horizontal sliding secondary glazing is often a popular choice as it can be fitted to a wide range of window styles, including sash and casement windows.

Fixed windows:

Fixed windows are a good option if you are looking for a low-maintenance secondary glazing solution. Fixed windows can be fitted to a variety of window styles, including casement and bay windows.

The cost to install secondary glazing to 7 windows in an average semi-detached house is around £2,600 but savings are only around £110 (= 202kg CO₂) a year. This means the payback period is about 24 years, additionally, it’s important to know that the environmental benefit of a reduced 202kg CO₂e footprint due to insulation only starts once the embedded CO₂ in the windows as well as the CO₂ generated during its transport and installation is removed from the equation. Note: we will supply CO₂e pay back periods at a later date.

Example of secondary glazing in front of picture window.

Curtains, sealed blinds and shutters

Curtains lined with a layer of heavy material or special thermal lining can reduce heat loss by 16% from a room through the window and cut draughts, however do not let your curtains hang over a radiator as this will stop the heat from radiating into the room.

Thermal lined curtains.

Hollow blinds, fitted into place with a sealed frame, and sealed shutters will help cut draughts and keep your heat in for longer.

Make sure you close curtains and blinds before it becomes dark and cold outside. Conversely make sure they are open in rooms which face the morning sun so that rooms can be heated by solar power.

Environmental tips

We recommend you avoid insulating window film – also known as secondary glazing film. You tape this transparent film onto the window to create a double-glazing effect however it stretches and tears easily and you have to replace it regularly.