Georgian Bars vs Astragal Bars: What’s The Difference?

If you’re researching heritage-style windows for your home, you’ve likely come across two terms that sound similar but mean very different things: Georgian bars and astragal bars. Both create that classic look of divided glass panes associated with period properties, but they sit on the glass differently, have distinct proportions, and lend themselves to different architectural styles.

This guide explains the key differences between Georgian bars vs astragal bars, how each affects sightlines and authenticity, and which option is the right fit for your home.

At a glance:

• Timberlook designs heritage-style uPVC windows and doors that replicate the look of original timber windows from the Georgian period and beyond.
• Manufactured using the patented Timberweld process (no tell-tale diagonal welds at the corners), our flush casement windows are a popular choice for both heritage homes and modern properties across the UK.
• Customisation options include Georgian bars, astragal bars, dual-colour finishes, and woodgrain effects – giving you the traditional appearance of timber windows with the energy efficiency and low maintenance of modern uPVC windows.

What are Georgian bars?

Georgian bars are the grid-style glazing bars that divide a window into smaller panes of glass. The name comes from the Georgian period (roughly 1714–1830), when glass-making technology limited the size of a single pane of glass. Windows of the era had to be made from multiple small panes held together by timber bars – creating the distinctive grid effect we still associate with Georgian sash windows today.

In modern windows, Georgian bars are usually decorative rather than structural. They’re most commonly fitted inside the sealed glass unit, sandwiched between the two panes of double glazing.

Key features of Georgian bars:

• Sit between the internal surfaces of the glass within the sealed unit
• Protected from external wear and weathering
• Create the illusion of smaller individual panes
• Easy to clean – no bars on the surface of the glass

What are astragal bars?

Astragal bars are the more authentic option for period properties. Rather than sitting hidden inside the glazing unit, astragal bars are applied to both external and internal surfaces of the glass, often with a matching spacer bar inside the sealed unit. This three-part construction is known as a duplex bar.

The result is a window that genuinely looks divided – with shadow lines, depth, and the same proportions you’d find on original timber windows.

Key features of astragal bars:

• Applied to the external and internal faces of the glass
• Typically paired with an internal spacer bar (duplex configuration)
• Creates authentic shadow lines and depth
• Closely replicates the look of traditional timber windows
• Approved for most conservation area applications

Astragal bars come at a higher cost than plain Georgian bars, but for period windows or properties in conservation areas, they often result in a much more authentic appearance.

Georgian bars vs astragal bars: the key differences

The most noticeable impact comes from where the bars sit. Georgian bars are positioned inside the sealed unit, giving a flat appearance with no shadow lines and an easier-to-clean glass surface. They’re a popular choice for modern homes wanting a hint of traditional character at a lower cost.

Astragal bars, by contrast, are applied to both external and internal surfaces of the glass – usually with a matching spacer bar inside the sealed unit too. This creates real depth and authentic shadow lines that closely match original timber windows. The trade-off is a higher cost and slightly more involved cleaning, but the aesthetic appeal on period homes is significant.

In short: Georgian bars work well from a distance and on modern homes; astragal bars deliver close-up authenticity for period properties.

Applied vs internal bars: which should you choose?

The choice often comes down to three factors:

Property age and style

Genuine Georgian or Victorian homes nearly always benefit from astragal bars. Modern homes can carry off either bar style, depending on personal preference.

Conservation requirements

If you live in a conservation area, check with your local planning officer before ordering. Many require duplex or astragal bars to preserve the heritage aesthetic.

Budget

Georgian bars (internal only) are the most affordable way to achieve a traditional look on larger windows. Duplex astragal bars cost more but deliver noticeable impact on kerb appeal.

What about energy efficiency and performance?

Whichever bar design you choose, it sits within a modern double glazing system with an insulating layer of gas between the panes.

Timberlook windows deliver exceptional thermal performance, with A rated glazing options available, plus noise reduction benefits – particularly useful in noisy urban areas. Multi-point locking and robust materials give homeowners peace of mind on security too.

About Timberlook: heritage for the modern age

At Timberlook, we believe your home deserves the best of both worlds. Our wood-effect uPVC windows and doors let homeowners enjoy the warmth and character of natural timber, paired with all the practical benefits of modern uPVC — it’s truly heritage for the modern age.

From beautiful flush casement windows to classic single and French flush doors, our range brings together heritage aesthetics, lasting warmth, exceptional thermal performance and reassuring security – making Timberlook a much-loved choice for period properties, conservation areas and modern homes alike.

Customising your Timberlook windows

Every Timberlook window is built to high industry standards and can be tailored to suit your home’s style. Options include:

• A wide range of colours including heritage colours like Painswick and Chartwell Green and woodgrain effects like Irish Oak and Rosewood
• Hardware options ranging from contemporary handles to heritage designs like Monkeytail and Peardrop handles
• A range of cills ranging from shallower contemporary cills to thicker heritage-style Radlington cills
• Trickle vents can be concealed with a large head drip for ventilation without disrupting the heritage look

Whether you’re matching period windows on a Georgian townhouse or adding character to a newbuild, our trusted Timberlook installers can help you find the ideal design.

Frequently asked questions

Are astragal bars worth the higher cost?

For period properties and conservation areas, yes. Astragal bars create authentic shadow lines that internal Georgian bars can’t replicate, making them a popular choice for homeowners who want a genuinely traditional appearance.

Do glazing bars affect natural light?

Only slightly. Bars create the illusion of smaller individual panes, which can reduce the open glass area marginally. However, the impact on natural light is minimal and most homeowners feel the aesthetic appeal outweighs it.

Will Georgian bars be accepted in a conservation area?

It varies. Some conservation officers accept internal Georgian bars; others require duplex astragal bars for full authenticity. Always check with your local planning authority before ordering.

Ready to find your perfect window? Contact Timberlook today

If you’d like to learn more about Georgian bars vs astragal bars, or you’d like to find your nearest Timberlook installer, fill in our online contact form, call us on b01253 888 222 or email sales@timberlook.com.

Our team will help you choose the right bar style, glazing unit and finish to suit your home.