


If you want elegant, flush windows with exceptional thermal insulation, there’s no better option than slimline triple glazed windows.
To explore your design options, download a brochure or request your free quotation.
Slimline triple glazed windows offer plenty of benefits, including enhanced thermal performance, which in turn can reduce your heating bills.
Energy bills are higher than ever. Triple glazing is much more efficient than double glazing, allowing it to keep more heat in and, in turn, save you money on your heating bill.
If you want a compelling stat, triple glazing offers up to 50% better thermal insulation than double glazing. With not one but two layers of inert gas, triple glazing makes it much more difficult for cold or warm air to pass through from the outside and into your home. This means you’re less likely to experience condensation, draughts or overeating in summer.
The extra layers of glass and air also contributes to slightly better sound insulation. This helps you keep the noise of the outside world where they belong – outside!
With three glass panels, your windows offer even more resistance against potential break ins or accidents playing cricket or football in the garden.
They also offer better UV protection – the main culprit for fading furniture!
All these benefits combined make your property more comfortable, resilient and even more attractive to potential buyers. So, if you’re thinking of putting a property on the market, slimline triple glazed windows could help you sell at a favourable asking price.

We offer a 10 year guarantee on all aluminium profiles and 25 years for the powder coating element
Stay warm in the winter and cool in the summer whilst cutting down on energy bills
Our team are flexible throughout the entire process, including the design and installation of windows
Klosen have over 25 years experience working with designers, architects and homeowners


A respected Spanish window manufacturer, Cortizo has designed slimline triple glazed windows since 1972.
With a choice of glazing finishes and stainless steel frames to reinforce the glass, the aesthetics of Cortizo are second to none.
Designed with a maximum window surface area to create light and space, these bespoke slimline aluminium windows are also designed with enhanced noise insulation as well as offering improved levels of energy efficiency and thermal insulation.


Origin supplies high-quality windows, backed by up to a 20-year parts warranty.
These premium aluminium frames are expertly engineered and undergo rigorous quality checks at Origin’s facility in Buckinghamshire before dispatch.
The frames are designed with a polyamide thermal break, significantly enhancing thermal performance to provide superior, future-proofed insulation for your home.
With a selection of 150 frame colours available, you can truly customise your aluminium windows with the perfect finishing touches to complement your property.
Based in Market Deeping, Lincolnshire, we cover towns and cities within a 60-mile radius.
Popular locations include Peterborough, Rutland, Bourne, Stamford, Huntingdon, Lincoln, Melton Mowbray and London, but we cover the entirety of Cambridgeshire and Lincolnshire.
We’ve installed stunning bespoke windows for homes and businesses for over 25 years. Our ethos is to take the hassle out of getting made-to-measure windows while ensuring the design fits the brief and fulfils future requirements for buildings.
Below are just some of the reasons customers appreciate working with us:
How much slimline triple glazed windows cost will depend on a range of factors, including which manufacturer you opt for, additional features and whether your installation has more specialist requirements. It is true that these windows have a higher price tag than double glazing, but this encompasses the improvements in thermal performance (which helps you save on energy bills).
U-values for triple glazed windows are lower than double glazed windows thanks to their enhanced thermal performance. Triple glazed windows made with a thermal break frame offer U-values as low as 0.71 W/m2K. This varies slightly between manufacturers, but all can achieve values below 1 for triple glazed windows.
Sound insulation is not a primary benefit of triple glazed windows, but due to the three panes of glass and two cavities of inert gas, this offers reduced noise.
SoundWe get that security is important for windows, especially if you’re installing for a family home or a property that contains high-value items. All our windows comply with PAS24 standards and with the three panes of glass, offer higher resilience against breakages than double glazed windows.