Windows for Hertfordshire Homes: A Guide by House Type

The right windows for your home depend more on when and how it was built than on anything else. Hertfordshire packs a lot into a small county: medieval streets in St Albans and Hertford, Victorian railway suburbs in Watford and Harpenden, the first garden city at Letchworth, Metro-land semis around Rickmansworth, and the first of the post-war new towns at Stevenage.

This guide sets out the main types of home across Hertfordshire, where each is most common, and the windows and doors that suit it best. It also covers the planning rules in each district, and the separate consent schemes in Letchworth and Welwyn Garden City.

Aliluxe designs, supplies and installs aluminium, uPVC and timber windows and doors across Hertfordshire, including Watford, Hemel Hempstead, Stevenage, St Albans, Welwyn Garden City and Harpenden. Every recommendation here comes from what we see on surveys.

Medieval and Georgian market towns

Many of Hertfordshire's old towns have timber-framed houses that were given brick Georgian fronts in the 18th century.

Where you'll find them

• St Albans: one of the first conservation areas in the country, designated in 1969. Fishpool Street is mostly medieval, with jettied houses such as The Crow and older buildings refronted in local red brick from the 18th century.

• Hertford and Ware: Hertford grew up around its castle, probably 12th-century, and has late Georgian fronts on Fore Street, such as No. 42. Ware kept its medieval street pattern and had 33 maltings by 1788.

• Sawbridgeworth: a planned 13th-century town with many 15th- and 16th-century timber-framed buildings, often behind Georgian fronts.

• Tring and Rickmansworth: late 18th- and early 19th-century workers' cottages and Georgian town houses in Tring, and 15th-century buildings in Rickmansworth's old centre.

What the windows are usually like

• Painted timber sliding sashes on Georgian fronts, including recessed 12-pane sashes.

• Timber casements, sometimes pegged, with leaded lights on the oldest buildings.

• A lot of older glass still in place on streets like Fishpool Street.

What we recommend

• Listed buildings need listed building consent for almost any window replacement or alteration. Timber is usually expected, and secondary glazing is often the most practical upgrade.

• Sliding sash windows suit Georgian fronts: REHAU uPVC sliding sash windows outside the most sensitive areas, and timber where the council requires it.

• On older cottages, timber or flush casement windows are the closest match. Every opening is measured individually, so frames fit walls that are out of square.

• Front doors: a panelled REHAU front door in a heritage colour suits most market-town fronts.

Victorian and Edwardian railway suburbs

The railway reached Watford in 1837, and the Midland main line reached Harpenden and Radlett in 1868. Streets of terraces and villas grew up around the stations.

Where you'll find them

• Watford: the Nascot area, with terraces on Bedford Street by 1849 and Victorian villas, was largely complete by the 1890s.

• St Albans: St Peter's Park is a planned late Victorian and Edwardian suburb, begun in the early 1880s, on roads such as Avenue Road, Hillside Road and Beaconsfield Road.

• Harpenden: the avenues west of the parish church were laid out in the 1890s, and Park Avenue in the early 1900s with detached houses on wide plots.

• Berkhamsted and Radlett: Victorian streets such as Kitsbury Road, Charles Street and Cowper Road in Berkhamsted, and Edwardian terraces on Watling Street in Radlett.

What the windows are usually like

• Timber sliding sashes, with bay windows on many houses (Upper Lattimore Road in St Albans has many).

• Arts and Crafts touches on some later houses, such as 78–84 High Street in Harpenden and Marlborough Gate (1923) in St Albans.

• Panelled front doors with stained or etched glass.

What we recommend

• Sliding sash windows keep the original look: REHAU uPVC sliding sash windows, or timber where the council requires it.

• For bays, keep the sash style across all faces, or use REHAU bay windows where the bay already has casements.

• At the back, a kitchen extension with aluminium bi-fold or sliding doors is the most common upgrade we fit on these houses.

• Check Article 4 first in Berkhamsted, where Article 4 directions cover houses on many of these streets and can mean you need planning permission for new windows (see below).

Letchworth and Welwyn Garden City

Hertfordshire is the home of the garden city. Building began at Letchworth, the first, in 1903. Welwyn Garden City followed: Ebenezer Howard bought the land in 1919, and the first homes were lived in from December 1920. Both still have estate schemes that control changes to windows, separately from planning permission.

Where you'll find them

• Letchworth Garden City: the original cottages and houses of the Heritage Character Area, built from 1903 onwards.

• Welwyn Garden City: the garden city planned by Louis de Soissons, with a neo-Georgian town centre, and the Estate Management Scheme covering most homes in Sherrards and Handside and parts of Haldens, Peartree, Hollybush and Howlands.

What the windows are usually like

• In Letchworth, hinged casements in wooden or mild steel frames, often with lead cames or timber glazing bars.

• In Welwyn Garden City, large white-painted timber sash windows on the neo-Georgian houses, and small-paned Crittall steel casements in some streets.

• Some homes in both towns now have later uPVC replacements.

What we recommend

• Get estate consent before you order. In Letchworth, the Heritage Foundation's consent is needed for any external change, even like for like. In Welwyn Garden City, the Estate Management Scheme's consent is needed for replacement windows, even in the same material.

• Copy the original design: opening pattern, glazing bars or leading, and colour. In Welwyn Garden City, uPVC is only considered where it matches the original style, design, proportions and colour.

• Where the originals were steel, the Letchworth Heritage Foundation normally expects mild steel, and considers other metals case by case. Heritage steel-look windows give the thin frames where they're accepted, and timber casements suit the cottage designs.

• We prepare the details the estate needs to see, including drawings of the glazing bar layout.

Metro-land, interwar homes and the new towns

The Metropolitan line reached Rickmansworth in 1887, and by the late 1920s Metro-land estates were spreading around it. After the war, Stevenage became the first new town in 1946, followed by Hemel Hempstead in 1947 and Hatfield in 1948.

Where you'll find them

• Rickmansworth: Metro-land commuter houses, built from the 1920s.

• Radlett and Harpenden: interwar mock-Tudor houses in Radlett's Rose Walk, and Harpenden's West Common area built from the 1930s.

• Stevenage, Hemel Hempstead and Hatfield: planned neighbourhoods of post-war houses. Hemel's plan was influenced by Geoffrey Jellicoe's idea of a town in a park.

What the windows are usually like

• Timber casements with leaded lights or small upper panes on interwar houses, and some steel Crittall windows.

• A two-storey bay at the front and a recessed porch on many interwar semis.

• On new-town houses, simple casements, many already replaced with uPVC.

What we recommend

• Casement windows suit these houses best. REHAU uPVC casement windows are good value, and Origin OW-80 aluminium gives a slimmer, flush finish.

• Where the originals were steel, heritage steel-look windows recreate the Crittall look with modern performance.

• For the bay, REHAU bay and bow windows keep the original shape. Ask about a structural check, as many 1930s bays have no proper lintel.

• Flats and upper floors: tilt and turn windows clean easily from inside, and Origin OW-70 slimline gives a modern look with more glass.

Conservation areas, Article 4 and estate consent in Hertfordshire

Before you choose windows, check whether your home is listed, whether it is in a conservation area, whether an Article 4 direction applies, and, in Letchworth or Welwyn Garden City, whether you need estate consent.

• Most houses, including houses in conservation areas without an Article 4 direction, can usually replace windows without planning permission, as long as the new ones are similar in appearance to the old (Planning Portal).

• Flats and maisonettes don't have the same permitted development rights as houses. Identical, like-for-like windows usually don't need permission, but windows that look different may, and if you're a leaseholder you may also need consent from your landlord, freeholder or management company (Planning Portal).

• Listed buildings need listed building consent for any significant works, inside or out, including windows (Planning Portal).

• An Article 4 direction removes particular permitted development rights, so if it covers windows, even a like-for-like replacement can need an application. The Hertfordshire directions we found are listed below. Not all of them are confirmed to cover windows.

• The Chilterns National Landscape (formerly an AONB) covers parts of west Hertfordshire, so check whether your address is inside it. It doesn't on its own stop you replacing windows like for like, but some other permitted development rights are tighter there (Planning Portal).

• Letchworth Garden City: the Heritage Foundation's Scheme of Management covers all freehold homes on the estate, and leaseholders may also need to apply under the terms of their lease. You need its consent for replacement windows and doors, and all external alterations need an application, even if like for like (Letchworth Garden City Heritage Foundation).

• Welwyn Garden City: the Estate Management Scheme, set up in 1973, covers most of the town. You need its consent for replacement windows, even in the same material, and uPVC is only considered where it matches the original style, design, proportions and colour (WGC Estate Management Scheme).

• East Hertfordshire: Article 4 directions confirmed in November 2017 cover the Bishop's Stortford Conservation Area. Houses there need planning permission for replacement doors and windows on any elevation visible from a road, waterway or public open space, and a second direction covers flats and commercial premises (East Herts Council).

• Dacorum: Article 4 directions cover houses on many streets in Berkhamsted, including parts of Kitsbury Road, Charles Street, Cowper Road, Shrublands Avenue and Station Road, and some properties in Tring. Each direction lists specific house numbers. The council says Article 4 directions remove permitted development rights for works such as replacement windows and doors, but its table doesn't say which works each direction covers (Dacorum Borough Council).

• St Albans: Article 4 directions cover Verulam and Fishpool Street, and Sopwell Lane and Albert Street, in the St Albans conservation area, and also the Cunningham Avenue and Childwickbury conservation areas. They remove some permitted development rights for houses, which is likely to include windows, so check the one for your street. The council warns against unsuitably designed replacement windows in its conservation areas (St Albans City and District Council).

• Hertsmere: Article 4 directions in parts of Bushey, Radlett, Elstree, Letchmore Heath, Potters Bar and Shenley can cover changes to windows and doors, and each one is different, so check the one for your street (Hertsmere Borough Council).

• Watford: Article 4 directions made in April 2013 in the Nascot and Oxhey conservation areas remove permitted development rights for alterations to houses, which can include windows, and the council lists residential directions in several other conservation areas too (Watford Borough Council).

• Three Rivers, Stevenage and Welwyn Hatfield: we found no Article 4 directions covering windows. North Herts has Article 4 directions in the Hitchin and Stockens Green conservation areas, made in October 2012, which remove permitted development rights for alterations to houses, and these can include windows. Broxbourne has six conservation areas, so check with the council. Rickmansworth's 2025 draft appraisal says further loss of timber windows should be resisted, and suggests extending controls to its residential streets.

Work done without the right consent can lead to enforcement and the windows being replaced at your cost. We check these rules for every survey, and can help with the application if one is needed.

Hertfordshire districts at a glance

District	Typical housing	Conservation areas	Windows that often suit
Broxbourne	Cheshunt, Hoddesdon, Victorian and Edwardian Broxbourne	6	–
Dacorum	Victorian Berkhamsted, Georgian Tring, Hemel new town	25	Sash, check Article 4 in Berkhamsted
East Hertfordshire	Medieval and Georgian Hertford, Ware, Sawbridgeworth, Bishop's Stortford	42	Sash, casements, check Article 4 in Bishop's Stortford Conservation Area
Hertsmere	Borehamwood, Bushey, Edwardian and interwar Radlett	15	Sash, casements
North Hertfordshire	Letchworth Garden City, Hitchin, Royston	44	Casements, estate consent in Letchworth
St Albans	Medieval St Albans, Victorian and Edwardian suburbs, Harpenden	19	Sash, casements in older streets
Stevenage	Old Town, first post-war new town	7	Sash and casements in the Old Town; new-town types vary
Three Rivers	Old Rickmansworth, Metro-land	22	Sash in the old town, casements on later houses
Watford	Victorian Nascot and Oxhey	10	Sash, casements
Welwyn Hatfield	Welwyn Garden City, Old Hatfield, Hatfield new town	10	Casements and sash, estate consent in WGC

Frequently asked questions

Do I need permission to replace windows in Letchworth or Welwyn Garden City?

Usually yes, from the estate, and sometimes from the council as well. In Letchworth, the Heritage Foundation's consent is needed for replacement windows, even like for like. In the parts of Welwyn Garden City covered by the Estate Management Scheme, its consent is needed for replacement windows, even in the same material. Estate consent is separate from planning permission or listed building consent, so you may need both. We prepare the details they ask for.

Can I fit uPVC windows in a Hertfordshire conservation area?

It depends on the house and the council. Outside Article 4 areas, a house that isn't listed can usually replace windows like for like without planning permission. In Letchworth and most of Welwyn Garden City you still need estate consent. Most councils prefer timber on historic fronts, and Rickmansworth's appraisal, for example, says further loss of timber windows should be resisted. We check the rules for your street at survey.

Which Hertfordshire towns have Article 4 directions covering windows?

Bishop's Stortford's conservation area has a direction that covers replacement windows and doors. Berkhamsted (parts of Kitsbury Road, Charles Street, Cowper Road and other streets), Tring, St Albans, Hitchin, Bushey, Radlett and Watford also have Article 4 directions, and many of these are likely to cover windows. We check whether the direction for your address covers windows at survey.

Do I need permission to replace windows in a flat?

Often. Identical, like-for-like replacements usually don't need planning permission, but windows that look different may, and rules vary by council. If you're a leaseholder, check your lease, as you may also need the freeholder's or management company's consent.

Do you cover my part of Hertfordshire?

Yes. We work across Hertfordshire, including Watford, Hemel Hempstead, Stevenage, St Albans, Welwyn Garden City, Cheshunt, Hatfield, Bishop's Stortford, Hoddesdon, Borehamwood, Hitchin, Letchworth and Harpenden.

More window guides

We have guides like this for Surrey, Kent, Hampshire, Sussex, Buckinghamshire and Berkshire, and for Central, North, South, East and West London.

Get a free survey

Tell us about your home and we'll recommend the windows that suit it, check whether it is listed, in a conservation area or covered by an Article 4 direction, and give you a fixed quote. Call 020 4581 8351, email sales@aliluxe.co.uk or request a quote online. You can also browse our uPVC windows and doors and aluminium windows.

Please note: This guide is for general information only and is not planning, legal or professional advice. Planning rules, Article 4 directions and council guidance change over time, and how they apply depends on your property, so always check with your local planning authority before you start work (and with your landlord, freeholder or management company if you're a leaseholder). Replacement windows and doors must also meet Building Regulations. Historical and local details come from council, Historic England and other published sources and were believed to be correct when this guide was written in October 2026. Aliluxe cannot accept responsibility for decisions made solely on the basis of this guide, and we'll confirm the rules that apply to your home at survey.