Harlequin Glass Ltd have built up an excellent reputation supplying and fitting quality double glazing in Stevenage, Hitchin, Letchworth, St. Albans and across Hertfordshire.

As a proud member of the Double Glazing Network, we offer exceptionally high quality uPVC windows and doors in Hertfordshire, as well as aluminium double glazing and uPVC conservatories.

With over 30 years of experience in the double glazing industry, you can trust us to deliver exceptional double glazing every time.

We pride ourselves on our impeccable customer service, preferring to liaise directly with our customers rather than use pushy, commission based sales-people. We also have our own building team, meaning that we never have to subcontract. Our team are incredibly polite, tidy and experts in their trade, and have an excellent reputation for installing beautiful double glazing in Hertfordshire.

Why Choose Harlequin Glass Ltd?

Harlequin Glass Ltd are the most recommended double glazing installer in Stevenage and across Hertfordshire, with a large majority of our work coming off references from previous customers.

Choosing your replacement windows or a new front door is a big decision – so why are we the correct double glazing installer for you?

  • You’ll receive a 10 year guarantee with every uPVC installation – our double glazing is made to last!
  • We are a local, Stevenage company, and we specialise exceptional customer service.
  • We have our own building team, making us more reliable than other installers as we never need to subcontract – plus we can do a range of work!
  • Our uPVC windows and doors use incredibly high quality uPVC from Liniar.
  • As a member of the Double Glazing Network, we’ve been accredited with producing high quality installations in Hertfordshire.
  • We care about the environment – all of our uPVC products are 100% lead-free and completely recyclable.
  • We have 30 years of experience in double glazing installations, and are craftsmen of our work.


We are proudly accredited by a range of institutions, meaning that you can trust us to deliver quality double glazing, every time.


As a proud expert installers of the Liniar uPVC multi-chambered profile, you can trust us to make your Hertfordshire home more energy efficient.

Liniar offers the most robust, energy efficient uPVC profile on the market, and we are proud to use it for our uPVC windows and doors.


Our windows and doors are fitted with Britain’s favourite locking system – Yale. Installed with a 10 year mechanical guarantee as standard, our Yale hardware is designed to last, plus you’ll receive up to £1000 towards your contents insurance in the unlikely event of a break-in.

Choose Harlequin Glass Ltd for incredibly safe windows and doors in Stevenage, secured by high quality Shootbolt locking systems.

Secured by Design

As an installer of Yale locking systems, our products are officially Secured by Design accredited, a police-preferred security scheme which ensures windows and doors are safe from attempted forced entry.

You can’t put a price on the safety of your loved ones, which is why we’ve chosen only the most highly regarded security measures on the market for our double glazed windows and doors.

Double Glazing Network

We are proud members of the Double Glazing Network, a thoroughly vetted group of installers who are regarded as the most reliable in the industry, and consistently deliver high quality results.

By choosing a member of the Double Glazing Network, you are guaranteed very high standards of workmanship, and exceptional customer service every time.


Online Double Glazing Prices

Start your online quote today for competitive double glazing prices in Hertfordshire!