What Calibre Systems does

Calibre Systems International Ltd is a Glasgow-based specialist windows and doors company (Company Number SC767071, registered in Scotland) operating a single showroom at Calibre House, 87 Middlesex Street. It supplies bespoke glazing and door systems across four material families — PVC (DPQ series), Aluminium (DA series), Wood (DDF series), Steel (Presto, Unico, OTIF lines) and hybrid combinations (Wood-Aluminium, PVC-Aluminium) — to both domestic customers (homeowners, period-property and conservation-area projects) and commercial clients (shopfronts, commercial entrances, fire-rated partitions, public facilities). The technical core rests on partnerships with seven manufacturers including ALUPROF (sliding and fire-rated aluminium systems), FAKRO (roof windows), OTIF (steel and glass), DAKRO (wood), Victorian Sliders (sash hardware), Pilkington (glass) and Eko-Okna (PVC), enabling product specifications such as U-values down to 0.75 W/m²K, EI30/EI60 fire resistance on MB-78EI, A+ BFRC ratings on EcoSlide, and acoustic insulation up to 40 dB.

The commercial model is project-based and quote-driven — no public pricing is disclosed — combining direct showroom sales with online booking and a dedicated Calibre Direct sub-brand channel. Go-to-market blends direct-to-consumer showroom engagement with enterprise-style project consultation, positioning every engagement as a 'partnership' from design through installation. Distribution is wholly UK-domestic and concentrated at the Glasgow showroom, with no third-party reseller network, no app, no public API and no disclosed software product layer.

Revenue mechanics are anchored in two streams: hardware sales of manufactured window and door systems, and professional design-plus-installation services carried out in-house. Customer acquisition is principally referral-driven, with the company stating that most business comes from word of mouth. The company is privately held with no disclosed funding rounds, no parent entity, no institutional investors, and no public ticker; ownership is consistent with a founder- or management-led specialist trade contractor. There is no headcount, revenue or financial disclosure in the source material.

Name

Calibre Systems

Legal name

Calibre Systems International Ltd

Website

https://calibresystems.co.uk

Company type

Private

Founded year

2023

Operating status

Operating

Headcount range

1–10 employees

Short description

Calibre Systems is a Glasgow-based specialist glazing company that designs, supplies and installs bespoke windows and doors in PVC, aluminium, wood and steel for UK homeowners, trade contractors and commercial clients via its Glasgow showroom.

Ownership category

akta.pro rank

Product category

Windows and Doors

NAICS

Glass and Glazing Contractors (238150)

akta.pro primary industry

Egress Window Installation/Replacement (HSAPAJAH)

Keywords

• Bespoke windows and doors
• Commercial glazing systems
• Fire-rated door systems
• Aluminium and PVC windows
• Roof and sliding doors

Headquarters

HQ city

Glasgow

HQ country

United Kingdom

HQ region

Europe

Offices1 record

Markets served

GTM type

B2B and B2C

Offering type

Hardware or Manufacturing

Cost components

Supply Chain, Personnel, Operations, Marketing or Sales, Technology or R&D

Revenue model

1. Window and Door Product Sales: Sale of bespoke glazing systems including windows and doors in various materials (PVC, Aluminium, Wood, Steel). Products are manufactured using high quality profiles alongside advanced double and triple glazing technology.
2. Installation Services: Full service offering including design consultation and professional installation throughout the design and installation process as a partnership approach with clients.

Go-to-market motion2 records

Distribution channels2 records

Marketing channels3 records

Core offering

Calibre Systems is a Glasgow-based specialist that supplies and installs bespoke windows and doors in PVC, Aluminium, Wood and Steel for domestic and commercial clients. Its range covers residential windows and doors, commercial doorsets, fire-rated door systems, sliding door systems (Skyline), sliding sash windows (EcoSlide) and roof/flat-roof windows from partner brands such as ALUPROF, DAKO, OTIF, FAKRO, Pilkington, Victorian Sliders and Eko-Okna. Projects are delivered through a design, supply and install service backed by a physical Glasgow showroom.

Product overview

Calibre Systems is a Glasgow-based specialist windows and doors company offering a comprehensive portfolio of bespoke glazing solutions. Their product range spans multiple material categories including PVC (DPQ series), Aluminium (DA series), Wood (DDF series), Steel (Presto, Unico), and hybrid combinations like Wood-Aluminium and PVC-Aluminium. They distribute products from partnered manufacturers including FAKRO for roof windows and OTIF for steel doors. The portfolio encompasses windows (residential and commercial), doors (entrance, sliding, bifolding, fire-rated), roof windows (pitched and flat), and accessories (blinds, flashings). Products target both domestic and commercial scale clients with a focus on energy efficiency through advanced double and triple glazing systems.

Differentiator

Problem solved

Functional benefit

Brands

• EcoSlide: Sliding sash windows - PVC sash windows as replacement for original timber sash windows, rated A+ for thermal performance.
• OTIF Steel Doors
• Skyline
• Calibre Direct

Products and services

• PVC Windows (DPQ Series)

Quantifiable outcome

• BFRC Energy Rating of 'A+' as standard on ECOSlide windows
• +2 more outcomes

Segments3 records

Ideal customer profiles2 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature4 records

Partnerships

Seven partnerships are on record, tiered core and supporting.

• ALUPROFcoreTechnology or IntegrationALUPROF is a key manufacturing partner providing the Skyline Type R sliding door system and MB-78EI fire-rated aluminium systems. Their products feature advanced thermal insulation, narrow profile designs, and high-performance specifications including hidden frame technology and automated drive units.
• FAKROcoreTechnology or IntegrationFAKRO is the fastest growing roof window manufacturer globally, providing pitched roof windows, flat roof windows, flashings, and blinds. Products are recognized for combining security, quality, and efficiency with modern aesthetics including Red Dot Design Award 2016.
• PilkingtonsupportingTechnology or IntegrationPilkington (glassworks) provides glass products integrated into Calibre Systems' window and door solutions, contributing to the thermal performance and quality of their glazing systems.
• DAKOsupportingTechnology or IntegrationDAKO provides premium wooden windows combining natural materials with manufacturing precision and craftsmanship. Their wood windows feature manual precision sanding and varnishing with quality control at every production stage.
• Victorian SliderssupportingTechnology or IntegrationVictorian Sliders manufactures ECOSlide sash window hardware to the highest quality standards, including pole eyes, tilt knobs, sash lifts, sash locks, and travel restrictors in various finishes.
• OTIFcoreTechnology or IntegrationOTIF is a leading manufacturer of steel and glass systems including doors, windows, and fixed elements. They offer three distinct product lines: Prestige (elegant, slender profiles), Industrial (strong, raw designs), and Pure (referencing English and American architecture).
• Eko-OknasupportingTechnology or IntegrationEko-Okna provides window and door products integrated into Calibre Systems' PVC and composite window offerings, contributing to their diverse product portfolio.

Scale indicators1 record

Recent moves6 records

Expansion highlights5 records

Direct peers

• Zenith Staybrite: UK home improvements company offering windows, doors and conservatories to homeowners. Directly comparable on product category, installation service model, and domestic customer base, though operating at greater scale.
• Anglian Home Improvements: UK national glazing and home improvement specialist offering windows, doors and conservatories across domestic and commercial segments. Directly comparable on product category and customer base, though much larger and more volume-oriented.
• Safestyle UK: UK-focused PVC and composite windows and doors installer competing directly in the domestic replacement glazing market. Comparable customer segment but positioned primarily in value-driven PVC rather than bespoke multi-material work.
• Origin Global: UK premium aluminium windows and doors specialist focused on the higher-end residential and commercial segment. Closely comparable to Calibre's aluminium and bespoke positioning, with stronger brand recognition in bifold doors.
• CR Smith: Scottish-based specialist windows and doors manufacturer and installer with a comparable multi-material product range (PVC, aluminium, timber) and similar domestic/commercial focus. Closest geographic and operational peer to Calibre Systems.
• Clearview Home Improvements: UK home improvement specialist installing windows, doors and conservatories. Comparable go-to-market (regional showroom-led, domestic focus) and overlapping product portfolio, particularly in PVC and aluminium systems.
• Everest: Established UK double-glazing and home improvements installer with a comparable window and door product set. Competes with Calibre in the domestic replacement segment, with broader geographic coverage but less bespoke specialisation.

Emerging players

• Masterframe Windows: UK specialist in PVC-U sash windows replicating traditional timber designs. Directly comparable to Calibre's EcoSlide product line and the period-property, conservation-area customer segment.
• Quickslide: UK PVC and aluminium windows specialist serving the trade and retail fabricator market. Comparable in product category but operates upstream in fabrication rather than end-customer installation.

Others

• ALUPROF UK: European aluminium systems manufacturer supplying the Skyline and MB-78EI product ranges that Calibre installs. Comparable as the upstream technology provider whose systems Calibre configures for end customers.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks5 records

Key highlights6 records

Customer concentration

• Facebookfacebook.com/Calibre-Systems-Glasgow-105138017939829
• LinkedInlinkedin.com/company/calibresystems

Revenue estimate

Valuation estimate

Number of profiles

Profiles1 record

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Calibre Systems