Georgian vs Victorian Windows: Period Style Identification & Replacement Guide

The quickest way is to count the panes. Georgian windows typically have 6, 8 or 12 panes per sash with slender glazing bars. Victorian windows usually have 1, 2 or 4 panes per sash with thicker bars or no bars at all. Look for sash horns (small projections at the bottom of the upper sash) — their presence indicates Victorian or later. Also check the build date of your property through land registry or local history records.

If your property is listed, almost certainly not — Listed Building Consent would be refused. In a conservation area, it depends on the local authority; some accept high-quality uPVC replicas, others insist on timber. Outside conservation areas, there is no restriction on material choice, and uPVC Georgian-style sash windows offer a cost-effective alternative at £500-£1,200 per window.

Sash horns are small timber projections at the bottom corners of the upper sash in a vertical sliding window. They were introduced in the Victorian era to provide additional structural support when glazing bars were removed and pane sizes increased. The presence or absence of horns is a key dating feature: Georgian windows never have horns, while Victorian and later windows almost always do.

Yes. Slim-profile double glazed units (12-16mm thickness) are now available that fit within the traditional sash rebate depth. These achieve a centre-pane U-value of around 1.2-1.4 W/m²K while maintaining the slender sightlines of period windows. Many conservation officers now accept slim-profile double glazing in listed buildings provided the overall appearance is not materially altered.

A full sash window overhaul — including new sash cords, draught-proofing, putty renewal, partial timber splicing where rotten, easing and adjustment, and full redecoration — costs £400-£900 per window. This is significantly less than replacement (£800-£3,000) and preserves the original historic fabric, which is important for listed buildings.

Crown glass was the standard window glass used in the Georgian era, made by spinning molten glass into a flat disc. It has a characteristic slight waviness and occasional tiny imperfections that give it a distinctive visual quality. When replacing glass in listed Georgian windows, conservation officers may require the use of reproduction crown glass or cylinder glass to match the original appearance. This adds £30-£60 per pane to the cost.

Like-for-like repairs (replacing rotten timber with matching timber, renewing putty, replacing sash cords) generally do not require Listed Building Consent as they count as maintenance. However, any alteration that changes the character or appearance of the window — including changing the glazing pattern, adding double glazing or replacing timber with uPVC — does require consent.

Through glazing bars (also called true or structural bars) run through the full depth of the sash and hold individual panes of glass on either side. Applied bars (also called plant-on or stick-on bars) are decorative strips attached to the surface of a single large pane to simulate the appearance of multiple panes. Applied bars are cheaper but look less authentic and are usually rejected for listed buildings.

Grants may be available from Historic England, local authority heritage funds, or the National Lottery Heritage Fund for listed building window restoration. Eligibility varies by location and building grade. Some local authorities also offer discretionary grants for properties in conservation areas. Contact your local conservation officer for details of available funding.

The Regency period (approximately 1811-1837) represents a transition between Georgian and Victorian styles. Regency windows often feature larger panes than Georgian (typically two-over-two or three-over-six) but retain the elegance and slender proportions of Georgian design. They may or may not have sash horns depending on the exact date and regional traditions.