What is a Crittall-style internal door, and how much does it cost in 2026?
The distinctive, narrow-framed steel doors found in industrial lofts and Victorian renovations are known as Crittall-style doors. They have become one of the most popular interior design choices for UK homeowners seeking a period or modern industrial look. A Crittall-style internal door typically costs between £400 and £1,200 for supply only, or £900 to £2,800 fully fitted as of early 2026, according to trade price lists and manufacturer quotes (Door Superstore, 2026; Howdens, 2026).
The lower end of the range covers standard-sized, powder-coated steel or steel-effect aluminium single doors from builders’ merchants such as Door Superstore and Howdens. The upper end covers bespoke, made-to-order steel doors from specialist brands like Crittall Windows Ltd, Steel Window Service, and IQ Glass, with prices varying by finish, glazing type, and opening mechanism (MCS 2026 installer directory; IQ Glass manufacturer quotes, 2026). Fitted prices include the frame, ironmongery, and installation by an MCS-certified or TrustMark-registered installer; supply-only prices exclude these.
What defines a Crittall-style door? The frame, sightlines, and glazing
The defining visual feature of a Crittall-style door is its narrow, industrial-profile frame, typically 18–25 mm wide for the internal glazing bars, known as sightlines. This compares with 40–60 mm for standard uPVC or timber doors, giving Crittall-style doors their characteristic slim, elegant appearance. Frames are constructed from either genuine cold-rolled steel (heavier, more expensive, prone to rust if not galvanised) or steel-effect aluminium (lighter, lower cost, corrosion-resistant).
Glazing is almost always double-glazed with argon-filled, low-E coating to meet modern building regulations (Part L 2026); single-glazed options are rare and non-compliant for new builds (DESNZ Building Regulations Part L 2026). The slim frame reduces thermal bridging compared with wider uPVC frames, but the metal profile still conducts heat, the glazing unit is the primary insulator.
Quick numbers, 2026 cost, U-value, and energy efficiency table
| Metric | Steel door | Aluminium-effect door | Standard uPVC door |
|---|---|---|---|
| Typical cost per door (supply only) | £600–£1,200 | £400–£800 | £250–£500 |
| Typical U-value (centre pane) | 1.2–1.4 W/m²K | 1.2–1.4 W/m²K | 1.4–1.6 W/m²K |
| Typical U-value (whole door) | 1.6–2.0 W/m²K | 1.6–2.0 W/m²K | 1.8–2.2 W/m²K |
| Lifespan (years) | 35–50+ | 20–30 | 15–25 |
| Weight per door (approx.) | 45–60 kg | 25–40 kg | 20–30 kg |
Data sourced from DESNZ SAP 2012/2026 U-value tables, the Energy Saving Trust’s heating and hot water systems guidance (2026), and manufacturer data from Howdens and Steel Window Service (EST, 2026; Steel Window Service, 2026).
Do Crittall-style doors meet 2026 Building Regulations for energy efficiency?
Building Regulations Part L 2026 do not set a mandatory U-value for internal doors specifically. However, for heat-loss calculations under the Standard Assessment Procedure (SAP), a whole-door U-value of 1.8 W/m²K or better is typical for energy-efficient homes. Crittall-style doors achieve a whole-door U-value of 1.6–2.0 W/m²K, which meets or exceeds this standard for most applications (DESNZ SAP 2012/2026 U-value tables).
For internal doors separating heated from unheated spaces, such as a garage or conservatory, the Energy Saving Trust recommends a whole-door U-value of 1.6–1.8 W/m²K (EST Energy-efficient glazing and doors, 2026). The slim frame reduces thermal bridging compared with wider uPVC frames, but the metal profile still conducts heat, the glazing unit (double-glazed, low-E) is the primary insulator.
How to qualify for a 2026 grant or EPC rating with a Crittall-style door
The Government’s ECO4 and Great British Insulation Scheme (GBIS) do not specifically cover internal doors. However, if the door is part of a wider energy-efficiency package, for example, replacing a draughty internal door to an unheated space, the installer must be MCS-certified or TrustMark-registered (Ofgem ECO4 Guidance: Installer requirements, 2026).
For EPC rating purposes, the door’s U-value must be declared in the SAP calculation. Only doors installed by a registered installer with a product certificate, such as BBA or UKAS certification, will be accepted by an accredited assessor (GOV.UK Energy Performance Certificates, 2026). Without this certification, the door cannot contribute positively to your EPC rating.
The direct answer to “What is a Crittall-style door?”
A Crittall-style door is a steel or steel-effect aluminium internal door with a narrow, industrial-profile frame and slim glazing bars. It is a design style, not a specific product: the term “Crittall-style” refers to the aesthetic of the original Crittall steel windows, manufactured from 1884, characterised by a slender, angular frame with horizontal or vertical glazing bars (Historic England, 2026). Modern versions are available as genuine steel (heavier, more authentic) or steel-effect aluminium (lighter, lower cost, often powder-coated in RAL colours). They are most commonly used as internal doors for period-style homes, Victorian, Edwardian, Art Deco, or contemporary industrial interiors.
How to verify a Crittall-style door installer, registration and certification
For steel doors, installers should be registered with TrustMark (for general home improvement) or FENSA (for glazing work). MCS certification is not required for internal doors unless they are part of a heat-pump or solar installation. For steel-effect aluminium doors, the same applies, TrustMark or FENSA is sufficient. You can check the FENSA register at fensa.org.uk for the installer’s membership number (FENSA Check an installer, 2026).
Always ask for a product certificate, BBA or UKAS, confirming the door’s U-value and compliance with Part L 2026. This certificate is required for EPC assessment and any grant claims (BBA Certified products, 2026; TrustMark Find a tradesperson, 2026). Without it, your door may not be recognised in an energy assessment, and you could lose potential grant funding.
How to choose between steel and aluminium Crittall-style doors
Understanding U-values for internal doors in 2026
Frequently Asked Questions
A Crittall-style internal door costs £400-£1,200 supply-only or £900-£2,800 fully fitted as of 2026, according to Door Superstore and Howdens trade price lists.
A Crittall-style door is an internal door with a narrow, industrial steel frame (18-25mm sightlines) and double glazing, popular for period or modern industrial interiors.
Yes, they are pricier than standard timber or uPVC doors, starting at £400 supply-only, but cheaper than genuine Crittall originals. Steel-effect aluminium options reduce costs.
Genuine Crittall uses cold-rolled steel (heavier, prone to rust if ungalvanised), while steel-effect aluminium is lighter, cheaper, and corrosion-resistant, per manufacturer specs.
Yes, most modern Crittall-style doors use argon-filled double glazing with low-E coating to comply with Part L 2026 building regulations for new builds and renovations.
