The investment marks the latest step in the transformation of the historic brand, founded in 1913, since it was rescued by Sandy and James Easdale in 2011.
Its wooden frame window business has since won contracts for Victorian buildings in the Olympic Park in London, the Black Watch museum at Balhousie Castle in Perth, the Anchor Line building in Glasgow’s St Vincent Street, Dunlop House in East Ayrshire and the legislative building in Ontario, Canada.
In the coming months, the Greenock factory will be transformed to make way for the introduction of automated machinery and systems for PVCu frames.
Managing director Alex Gray said: “This investment demonstrates that we are highly committed to making Blairs Windows Limited the most competitive, sustainable and innovative window and door manufacturer in Scotland.
“It is a historic brand whose name is renowned for quality and it’s important that we keep evolving to ensure we are providing the very best service to our customers. This is a real sign of confidence in our product, our suppliers and most importantly, our employees.”
The move into plastic follows the formation of the Saveheat Group in 2017, which includes Blairs Windows, Blairs Aluminium, Merlin Network and Saveheat Glass.
Co-owner Sandy Easdale said: “We’ve been delighted with the progress Blairs has made over these past seven years. We have real faith in the Blairs workforce and this investment will allow further development in the company and the markets we can cultivate.”