Between the 1600 – 1800’s glass was very expensive and windows were made by blowing glass and then spinning into a large circular flat plate. Once the glass was cooled it was cut into small panes. The central piece which had been attached to the blowing iron called the bulls eye was the cheapest part of the glass.


Hence windows in older buildings had to have many glazing bars due to lack of availability of larger glass panes. The metal was also there to give strength to the structure of the window.

Single glazing however is not ideal for keeping in the warmth and condensation forms on the window when the warm area from inside meets the cold pane of glass.

Condensation on glass panes in a single glazed window


It wasn’t until Float glass was invented in the 1950’s, where glass is poured onto a molten tin layer where it floated and gave a smooth and flat finish, that large pains of glass became more readily affordable.

When installing new aluminium windows, it is important to ensure that your property retains it’s character. Large panes of glass may not be in keeping with a period property or may not be permitted in a conservation area.  If you house is a listed building, you will need to seek advice before removing or replacing windows.

Both Astragal bars and Georgian bars are bars that are fitted to modern double glazed windows or doors to give a Georgian bar feature like Georgian sash windows. The bars are cleverly fitted inside the glazing and also on the outside of the window to give a similar appearance of smaller panes.  The glazing is usually one large pane to fit the whole of the window.

Georgian or Astragal bar


In some houses it is necessary to match existing window styles or in some cases to conform to planning restrictions, to be in keeping with the area. With the use of either a Georgian Bar or Astraal you can have all the benefits of modern double glazing and  ensure your house fits with its period surroundings. Cottage windows or older properties often have either small windows or many small panes of glass. To remove the windows and replace with large panes would spoil the overall look of the property. If you do live in a cottage or older property it is worth checking with the local planning department before having replacement windows.

If you want new windows that match to existing windows  then give us a call or visit our showroom on Callywhite Lane, Dronfield.

and you can find out more about our aluminium windows here

What is the difference between an Astragal bar and a Georgian bar?

By using either Astragal bars or Georgian bars it negates the use of individual smaller pains of glass.

Georgian Bars

The Georgian bars are fitted inside the double glazed panel to give the appearance of smaller panes of glass. From a distance it is difficult to see that they are an internal bar, however on close inspection it is easy to make out that they are fitted internally. The bars are installed during the making of the double glazed panel and sit between the 2 panels of glass within the sealed double glazed unit. These are called Georgian bars.

Astragal Bars

These bars are fitted to the outside of the double glazed unit. An astragal bar stands proud of the glass. If astragal bars are to be fitted to a window or door, the sealed glass unit will contain a back to back or duplex bar. When viewed close to the window, it gives the appearance that a number of smaller double glazed units have been used, whilst the astragal bar sits on the outside of the glass, replicating the old glazed bar.

If you are having aluminium frames, the astragal bar can be powder coated to match the colour of your frames. Over 200 RAL colours are available for powder coating. The bars can be placed so that they match existing windows in your property.

Crittall Style Replacement Windows

The astragal bars can be fitted to windows and doors to emulate Crittall Style windows.

Cost of Crittall Style Replacement Windows

The cost of Crittall style windows and doors is dependant on lots of factors – the size of the opening, the type of glass that you wish to install, and the number of bars. If you are looking for a quote, don’t hesitate to contact us.

Here is a property we have recently completed in the Peak District.  The windows being in keeping with the area. ( the protection tape is still on the windows as the building works were not completed when the pictures were taken, so were left with the tape to afford some protection until the works had been finished.)

Crittal style windows Derbyshire

Crittal style windows Derbyshire