
Many older properties take pride in their beautiful historic sash windows that give character and charm to the home. Preserving traditional architectural features is important for maintaining the integrity and appeal of old houses, but homeowners also want the benefits of modern windows.
Replacement is not always necessary; the sash window can be refurbished and a double glazing unit installed while keeping the original divided-light aesthetic using interior Georgian bars or exterior astragal bars.
These detailing options allow modern window technology to existing windows. Homeowners can decide which option best suits the architecture and style of their property. So while the windows may function like new, they retain the period features and detailed craftsmanship that make older windows special.
But now the question is – do you go with Astragal bars or Georgian bars? Let’s look at these options to narrow your selection margin.
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What is an Astragal Bar?

An astragal bar is a narrow strip of wood, metal or plastic placed between glass panes on a window. It is used to give windows the appearance of having multiple panes of glass, even though the window may have a single pane of double-glazed glass.
Astragal bars are applied to the inside and outside surfaces of the glazing bars. They stick out from the glass, dividing it into sections and imitating multiple panes of glass. This gives the window a more traditional, period look.
What is the purpose of Astragal Bars?
Overall, the primary purpose of astragal bars is to give windows the appearance of having multipaned glass, even when they use a single pane. This can help windows match the style of period properties while providing benefits like slightly improved security and privacy. Here are the several uses of astragal bars:
Aesthetics
The main purpose of astragal bars is to give windows an aesthetically pleasing traditional divided-light appearance. They imitate the look of multipaned windows from historical periods like Georgian or Victorian times. Astragal bars help match traditional styles that people find attractive and complement certain architectural designs.
They allow modern windows to match the aesthetic of older homes, resulting in a cohesive look. The window glazing remains a single pane of double-glazed glass, but the astragal bars dividing it make it appear like multiple panes from the outside. This can enhance the curb appeal and traditional charm of a property.
Security
While astragal bars primarily serve an aesthetic purpose, they offer some minimal security improvement. By dividing the window glazing into sections that appear like multiple panes of glass, astragal bars make it marginally harder for burglars to break through the glass in one go. They have to break through each seeming “pane” separately.
This slows intruders down slightly and makes it more difficult to force entry through the window. However, astragal bars do not provide the same level of security as true multipaned windows, where each pane is a separate piece of glass. But they provide a small boost in security that complements their aesthetic purpose.
Privacy
Another secondary benefit of astragal bars is that they slightly increase the privacy of windows. Since the glazing is divided into separate sections by the bars, it is harder for people outside to see clearly through multiple panes at once.
There are more potential obstructions to line of sight through a window with astragal bars versus a single pane of glass. While the improvement in privacy is minor, it does complement the aesthetic and slight security benefits of astragal bars.
Support
In some older historic windows, astragal bars served a structural purpose by helping support and hold the multiple individual window panes in place.
However, in modern windows with a single double-glazed glass pane, astragal bars serve an aesthetic purpose and provide no actual structural support. They imitate the look of traditional bars in older windows but fulfil no load-bearing function.
What is a Georgian Bar?

A Georgian bar is a thin vertical strip of wood or metal that divides a windowpane into smaller panes, giving the appearance of multiple panes of glass. They are not fixed to the exterior or interior of the glass like astragal bars. Instead, Georgian bars are sandwiched between the two panes of a sealed double-glazed unit. This means the bars are completely sealed within the window unit, not applied to the surface.
What is the Purpose of Georgian Bars?
The main purpose of Georgian bars is aesthetic, to give windows a more traditional appearance that is characteristic of Georgian architecture from the early 18th century. However, they also offer some additional benefits:
Aesthetics
The main purpose of Georgian bars is to replicate the traditional aesthetic of Georgian windows from the early 18th century. During this period, windows were made up of multiple panes of glass separated by thin wood mullions. Georgian bars mimic this divided-light design by dividing large panes of modern double glazing into smaller sections.
This creates the illusion of multiple panes of glass, which helps modern windows match the historic architectural style of Georgian properties. The bars give windows a more elegant, period appearance, enhancing the curb appeal and traditional charm of Georgian and Neoclassical homes.
Privacy
By splitting large panes of glass into smaller sections, Georgian bars provide slightly more privacy than single-pane windows. People outside have a harder time seeing fully through the various panes created by the bars. The divisions between panes break up their line of sight.
While the increase in privacy is minor, it enhances the aesthetic purpose of Georgian bars by making windows appear more separated and segmented like traditional ones.
Security
Though not as secure as true multipaned windows, Georgian bars offer marginally better security. Burglars have to break individual panes created by the bars to gain entry, which takes slightly longer and makes forced intrusion slightly more difficult.
However, their security benefits are limited since the bars are sealed within the double-glazed unit. They primarily serve an aesthetic purpose with just a small advantage for security.
Durability
Unlike astragal bars applied externally, Georgian bars are sandwiched between the two panes of a sealed double-glazed unit. This Internal position makes them more durable and easier to maintain. They are protected from the elements and require no external paint or finishing.
This helps Georgian bars have a longer lifespan with less wear and tear than astragal bars. Their sealed position also makes cleaning easier since no exposed external surfaces exist.
Which is Better: Astragal Bars or Georgian Bars?
Astragal and Georgian bars can add elegance and authenticity to period properties. However, some key differences make one option better suited for certain homes:
Authenticity
Astragal bars are applied directly to the exterior and interior glass surfaces. This provides a more true-to-life imitation of the original multipaned windows.
Astragal bars mounted on single double-glazing panes can come very close to replicating the look of genuine period casement windows. In contrast, the more hidden nature of internal Georgian bars means they provide a less authentic imitation of divided-light windows.
For properties where looking as close to the original as possible is essential, such as listed buildings, astragal bars typically offer a more historically accurate option.
Maintenance
Georgian bars have an advantage when it comes to maintenance. Sealing within the double-glazed unit requires no external paint, finishing or upkeep. Astragal bars applied to the external glass surface are exposed to the elements and require more frequent repainting, cleaning and maintenance.
Over time, astragal bars tend to show more wear and tear compared to internal Georgian bars. Georgian bars are generally better suited for homeowners who prefer lower maintenance options.
Cost
Astragal bars are often a more affordable option. Since they are mounted externally on the glass, they are simpler and cheaper to install than internal Georgian bars.
The increased complexity of sealing Georgian bars between two panes of glass during window manufacturing tends to make them a pricier choice. Astragal bars typically offer better value for money for budget-conscious homeowners due to their lower upfront cost.
Verdict
Astragal bars are generally the better option for properties that value historical authenticity and accuracy. Georgian bars work better for those prioritising lower maintenance requirements and durability over absolute authenticity. The lower cost of astragal bars is also an advantage for homeowners on a budget. Ultimately, you must weigh factors like authenticity, upkeep, and cost based on your home’s needs and priorities.