
Designed to suit contemporary and traditional homes

Police approved, Secured by Design, and PAS 24 2016 tested for security

Take advantage of our in-house colour match service

Made in Britain to the highest standards. Customer satisfaction always a priority.

we take care of everything

for over 50 years

all our tradespeople are fully qualified and expertly trained

complete with emergency call-out service
“one of the most cost-effective ways to improve thermal performance.” – Historic Scotland, May 2022
Homeowners choose secondary glazed windows because they’re quiet, warm and secure. These three features are the bedrock of our unique secondary glazing system and are the reason why so many homeowners are adopting secondary glazing.
Our entire suite of bespoke secondary glazing products is backed by a comprehensive 5-year guarantee.
Secondary glazing offers the most effective method of noise reduction, significantly outperforming other glass solutions by up to 80%*.
Secondary glazing acts as an additional deterrent to any would-be intruders and creates a further layer of defence against forced entry.
The sleek, modern design of our secondary glazing systems ensures that you’re able to enjoy all the acoustic, thermal and security benefits, without having to compromise on style.
Fitting secondary glazing inside, next to your existing windows, provides a small gap between the two. This effectively acts as an insulator, creating a separate layer of air which can reduce heat loss by up to 65%*.
Our bespoke secondary glazing range is an ideal solution for listed properties and homes within conservation areas. Where replacement windows are not a viable option, secondary glazing provides all the thermal and acoustic benefits you’d expect from from a modern window, without damaging the unique aesthetics of the primary window.
Improving the thermal and acoustic performance of your listed property shouldn’t negatively impact the character of your home. Our entire range of bespoke secondary glazing products come equipped with durable, slimline aluminium frames that accentuate the styling of the existing window.
Installing secondary glazing is the most effective method of keeping external noise out and keeping the heat in. Our ultra high performance frames can reduce external noise levels by up to 80% and reduce heat loss by up to 65%. All this whilst retaining your property’s authentic aesthetics*.
Each of our six unique product types are available as part of our Classic or Enhanced range. With each range offering slim sight lines, easy installation and exceptional thermal and acoustic performance, you’ll be truly spoilt for choice.
Classic. Classic products can accommodate 4mm glazing and come fully equipped with slimline, durable frames. Providing exceptional style, functionality and performance, they keep homes quiet, warm and secure.
Enhanced. Everything you’d expect from secondary glazing but with ultra-strong aluminium frames that support up to 10.8mm glass for enhanced noise reduction and thermal insulation. Our enhanced frames are super-sleek for superior, unobtrusive aesthetics.
Opening from top to bottom, our vertical sliding units are also available with a special slide pass or tilt in function, which enables both panels to individually pivot inwards for easy access and cleaning.
Our fixed units are an independent window that is permanently fitted on the inside of the existing window.
Suitable for a range of windows, including both casement and fixed, our horizontal sliding units open from side to side and are slim, versatile and easily accessed for both cleaning and ventilation.
Our guarantee is our commitment to look after our customers, and their products, for a period of five years from the date of installation. This guarantee covers both the product and workmanship, and we will never hesitate to honour our obligations under its terms.
Secondary glazing is a discreet second window fitted to the inside of an existing window that is designed to help reduce noise and provide added insulation.
Secondary glazing is ideal for listed buildings or conservation areas where there might be restrictions on new double glazing or more contemporary styles. Indeed, Historic Scotland and many local planning departments advise that secondary glazing is the most cost-effective method of improving energy efficiency in those cases.
Yes, we believe fitting secondary glazing is the best solution to achieve a reduction in noise. We can advise you on the optimum specification for your home and circumstances.
Our Discreet FitTM frames are extra narrow and carefully designed so they align with the frames of your existing windows to cover as little as possible, so the overall appearance is maintained.
We offer the very best, market-leading finance rates for all NJW Smith windows and doors. You can choose to pay nothing for 12 months other than a small deposit at an APR of only 2.9% representative or get up to four years interest-free credit with a 50% deposit. Sign up to our newsletter below for the latest seasonal offers.
Our secondary glazing is purpose-built to allow easy cleaning, both inside and out, no matter which style you select.