History and Teams

About us

GDL is a privately owned manufacturer and supplier of a large range of louvre systems, air diffusers, grilles, natural ventilation systems, brise soleil and dampers. From our head office in Glossop, Derbyshire and manufacturing facility in Sheffield,

GDL has serviced the built environment industry for over 30 years working with designers, architects and contractors across the UK and overseas.

GDL offers a vast wealth of experience in technical, manufacturing and product development fields, ensuring our customers are supplied with the choice of products most suited to their requirements. Our comprehensive regional sales representation across the UK and Ireland offers a wealth of expertise and knowledge across our entire product range.

We are committed to maintaining both the best quality products in the industry whilst maintaining the highest levels of customer satisfaction. GDL continue to uphold quality and environmental management systems that are certified to ISO 9001 –  Quality Management, ISO 14001 – Environmental Management & ISO 45001 – Health & Safety.


Our Mission

To successfully develop, manufacture, supply and install high quality products to the construction industry in a socially responsible way and for the benefit of all stakeholders.

Experts in Air Systems

Meet the Team

Tom Callaghan

Tom remains ever present within the business today, predominantly looking at innovation and product development.

Tom Callaghan


Tom founded the company as it is known today back in 2004 having worked in the HVAC industry for over 50 years.

Phill Callaghan

Phil enjoys the day to day challenges and rewards the role presents whilst continually looking to help develop the business.


Phil Callaghan


Phil has been involved with GDL Air Systems Ltd since its formation in 2004 and over the past 20 years has helped the company grow and expand on all fronts.

He oversees all areas of GDL’s policies from health and safety through to commercial sales and project installations.

Debbiw Kuczaj

Debbie always monitors the supply and demand of the industry therefore ensuring GDL will always offer the most competitive of prices.


Debbie Kuczaj


Debbie joined GDL in 2009 where she formed part of the Internal Sales Team before progressing onto leading the external sales team for the following 2 years.

Appointed as Sales Director in 2011 she now leads and motivates the Sales Team whilst developing customer relationships, increasing GDL’s market share and managing their sales revenue.

Daniel Leatherbarrow

Daniel thrives on building customer & client relationships alongside helping GDL with their business development.


Daniel Leatherbarrow


Daniel joined GDL in 2011 and is an active member of the projects team. He can deal with initial enquiries and orders through to their subsequent management and completion.

He has successfully been involved with several high profile projects whilst at GDL including the illustrious Battersea Power Station regeneration and the construction of the New U.S. Embassy in London.

Ross Dunlop

Ross has over 23 years’ experience working for GDL and currently heads up our projects team.


Ross Dunlop


Ross has gained vast experience in many areas of the business such as Estimation, Project Management, Product Development, CAD, Controls Design & Commissioning.

He is technically astute and can help with all enquiries that relate to GDL products.

John Jozefczyk

John is an integral part of the sales team with exceptional knowledge and customer service skills.


John Jozefczyk


John progressed from the shop floor bringing his knowledge into the estimating office where he showed his true talent in returning quotations efficiently whilst converting them into sales.

Additionally John offers IT support within the office and helps address any subsequent issues.

Paul Callaghan

Paul is excited to be a part of all things GDL.


Paul Callaghan


Paul has been with the company since 2008 and initially headed up the operations in the South East of England.

Paul progressed onto the commercial side of the business over the following years and has recently returned back to the business following a long period off due to ill health.

He is now looking forward to getting back involved with all things GDL.

Daniel Leatherbarrow

Sarah started working at GDL in 2005, managing all the functions of the accounts department.

Sarah McKenzie


Sarah’s work routine covers the management of the GDL accounts, credit control and communication with HMRC.

Sarah primarily grew up and gained her accounting qualifications in South Africa before returning back to England in 2001.

UK Coverage


We manufacturer quality ventilation, air conditioning and architectural products for our clients throughout the country.


To supply the highest quality products.

Fair Prices

A fair and consistent price on our full product range.


Dedicated technical support and industry expertise.


100% commitment to customer satisfaction.