What Thermaseal does

Thermaseal Windows & Doors Ltd is a Nottingham-based, family-run installer of residential fenestration products and home improvement services, founded in 1993 and operating from a single headquarters at Unit 4 Brand Street, Nottingham NG2 3GW. The company serves homeowners and trade professionals across Nottinghamshire, Mansfield, Derby, and surrounding East Midlands areas, with a stated geographic limit to the East Midlands region.

The core product portfolio spans uPVC and aluminium windows (casement, sash, tilt and turn), uPVC and composite front doors, French, patio, and bi-fold doors, conservatories and orangeries (including full design and build), replacement conservatory roofs (warm roof systems), roofline products (soffits, fascias, guttering), and made-to-measure porches. Technical components include A-rated energy-efficient glazing using 28mm Planitherm Argon-filled units, multi-chambered uPVC profiles, low-emissivity glass with warm-edge spacer bars, Kubu bi-directional locking systems, and warm roof construction with plasterboard interiors. The company is Certass-accredited, Secured by Design accredited on composite doors, and meets British Standards across its product range.

Thermaseal operates a sales-led, direct-to-consumer go-to-market with no-obligation free surveys and quotes (typically 24–48 hour turnaround), home visits for design consultations, and a physical trade counter at the Nottingham location for walk-in trade and DIY customers. Revenue is generated through one-time product sales bundled with installation services, plus trade counter hardware sales. The company differentiates through local reputation (4.9/5 Google rating), 10-year insurance-backed guarantees, 24-hour aftercare response, and an end-to-end design-and-build service that includes electrical, plastering, and finishing work. The firm is privately held with no disclosed funding, no public listing, and 6 disclosed employees.

Name

Thermaseal

Legal name

Thermaseal Windows & Doors Ltd

Website

https://thermaseal.uk.com

Company type

Private

Founded year

1993

Operating status

Operating

Headcount range

1–10 employees

Short description

Thermaseal is a Nottingham-based family-run installer of windows, doors, conservatories, and roofline products serving homeowners and trade professionals across the Nottinghamshire/East Midlands region of the UK.

Ownership category

akta.pro rank

Product category

Window and Door Installation Services

NAICS

Building Material and Garden Equipment and Supplies Dealers (444)

SIC

Retail-Building Materials, Hardware, Garden Supply (5200), Retail-Home Furniture, Furnishings & Equipment Stores (5700)

akta.pro primary industry

Doors, Windows & Millwork Retail (Interior/Exterior Doors, Windows, Moulding) (CRAIAEAI)

Keywords

• Window installation services
• Door installation services
• Conservatory construction
• Home improvement services
• Fenestration products

Headquarters

HQ city

Nottingham

HQ country

United Kingdom

HQ region

Europe

Offices1 record

Markets served

GTM type

B2C

Offering type

Services

Cost components

Supply Chain, Personnel, Operations, Marketing or Sales, Others

Revenue model

1. Window Sales and Installation: Design, supply and installation of uPVC and aluminium windows in various styles (casement, sash, tilt and turn). Revenue generated through product sales plus professional installation services.
2. Door Sales and Installation: Supply and installation of uPVC and composite front doors, French doors, patio doors, and bi-fold doors. Includes multi-point locking systems and energy-efficient glazing.
3. Conservatory and Orangery Construction: Full design and build service for conservatories and orangeries. Includes tiled, glass or lantern roofs, electrical, plastering, and finishing work. 3D design visualization provided before installation.
4. Roofline Products and Installation: Supply and installation of uPVC fascias, soffits, and guttering. Full replacement services with no capping over existing boards.
5. Trade Counter Retail: Retail sales of window and door materials, glass cleaner, locks, bolts, and security fittings to trade professionals and homeowners from the trade counter location.
6. Porch Installation: Custom design, supply and installation of made-to-measure porches including groundwork, brickwork, roofing, doors, and windows.

Pricing tiers

Go-to-market motion2 records

Distribution channels3 records

Marketing channels5 records

Core offering

Thermaseal designs, supplies, and installs windows, doors, conservatories, orangeries, replacement conservatory roofs, porches, and roofline products for residential customers across Nottinghamshire. The business also operates a trade counter serving local trade buyers and provides aftercare and maintenance support across its installed product base.

Product overview

Thermaseal is a Nottingham-based family business offering a comprehensive range of home improvement products and installation services. The core portfolio includes uPVC and Aluminium windows (casement, sash, tilt & turn styles), uPVC and composite front doors, and French, patio, and bi-fold doors. The company also supplies and installs conservatories, orangeries, replacement conservatory roofs (solid tiled and hybrid warm roofs), soffits/fascias/guttering, and porches. These products are offered alongside full design and build services for complete project delivery and ongoing aftercare support. All installations are performed by Certass-registered professionals with insurance-backed guarantees.

Differentiator

Problem solved

Functional benefit

Products and services

• uPVC Windows
• Aluminium Windows
• uPVC and Composite Front Doors
• French, Patio, and Bi-Fold Doors
• Conservatories and Orangeries
• Replacement Conservatory Roofs
• Soffits, Fascias, and Guttering
• Porch Installations
• Trade Counter Supply Service
• Aftercare and Maintenance Support

Quantifiable outcome

• A-rated energy efficiency as standard on all windows
• +2 more outcomes

Named customers4 records

Segments2 records

Ideal customer profiles2 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature5 records

Partnerships

Four partnerships are on record, tiered core and minor.

• CertasscoreOthersCertass-accredited installation service. All installations meet strict quality and safety standards. Certification ensures guarantees are insurance-backed. Required for compliance and customer peace of mind.
• PlanithermcoreTechnology or IntegrationSupplier of Argon-filled glazing units used in Thermaseal windows. 28mm Planitherm Argon-filled glazing provides thermal efficiency and energy performance for A-rated window installations.
• KubucoreTechnology or IntegrationProvider of bi-directional locking systems used in Thermaseal windows. Kubu-ready systems provide enhanced security and smart home monitoring capability for window installations.
• Midland Improvements (MIDIMP)minorStrategic or Co-development PartnerRoofing solutions supplier/backer. Mentioned as a trusted supplier providing products for conservatory warm roof installations.

Scale indicators6 records

Recent moves5 records

Expansion highlights4 records

Others

• Eurocell: UK uPVC profile extruder and building plastics distributor whose window and roofline profiles Thermaseal uses. Acts both as a Thermaseal supplier and as a competing trade-counter outlet for trade professionals in the same geography.
• Pilkington (glass supplier): UK glass manufacturer that supplies double-glazing units used by Thermaseal installations. Enabler/ecosystem rather than competitor — adjacent in the fenestration supply chain, listed as a Thermaseal supplier partner.
• Planitherm (by Saint-Gobain): Saint-Gobain's energy-efficient glazing brand supplied to Thermaseal for A-rated window units. Ecosystem supplier rather than direct competitor, but its technology roadmap directly affects the differentiation Thermaseal can market.

Direct peers

• Lockwood Windows: Yorkshire-based regional installer of uPVC and aluminium windows, doors and conservatories with survey-led direct sales. Closely comparable scale and motion to Thermaseal, serving neighbouring northern UK regions.
• KJM Aluminium: UK installer specialising in aluminium windows, doors and roofline products with a direct-to-consumer survey-based motion. Comparable on aluminium product depth and homeowner target, though stronger on aluminium and weaker on uPVC versus Thermaseal.
• Zenith Staybrite: UK regional window, door and conservatory installer operating with a similar direct-to-consumer survey-led model. Comparable business size and service offering to Thermaseal, competing for the same homeowner improvement budgets in regional UK postcodes.

Regional players

• CR Smith: Long-standing Scottish-based window, door and conservatory manufacturer-installer. Highly comparable product mix (uPVC, aluminium, conservatories, roofline) but concentrated in Scotland rather than competing head-to-head with Thermaseal in the East Midlands.

Broad incumbents

• Everest: Long-established UK installer of windows, doors and conservatories with a national sales force and finance offering. Same product categories, same homeowner target, same survey-led direct-to-consumer motion as Thermaseal.
• Anglian Home Improvements: UK's largest home improvements company selling windows, doors, conservatories and orangeries nationwide with in-home selling and finance. Overlaps directly with Thermaseal's core windows/doors/conservatory offering but at vastly greater national scale and marketing budget.
• Safestyle UK: National value-positioned UK window and door installer selling uPVC products with a high-volume direct-sales model. Direct overlap with Thermaseal on uPVC windows and composite/uPVC doors at the budget-to-mid price tier.

Market position

Strengths4 records

Weaknesses4 records

Competitive moat4 records

Key risks5 records

Key highlights6 records

Customer concentration

• LinkedInlinkedin.com/company/thermaseal

Compliance5 records

Revenue estimate

Valuation estimate

Number of profiles

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 Thermaseal