Replacing your windows and doors is one of the most valuable improvements you can make to your property. Whether you’re renovating a Victorian terrace, upgrading a family home, or improving a commercial property, choosing the right double glazing company in London is just as important as selecting the right products. Even the highest-quality windows will fail to perform if they aren’t installed correctly.
With hundreds of double glazing installers in London, finding a reliable company can feel overwhelming. Every business promises competitive prices and exceptional service, but not every installer delivers the same level of craftsmanship, product quality, or aftercare. The right company should provide more than just new windows—they should offer expert advice, premium glazing systems, professional installation, and long-term support.
If you’re investing in replacement double-glazed windows, aluminium bifold doors, sliding patio doors, or uPVC windows, this guide explains what to look for before making your decision and why choosing premium systems such as Cortizo aluminium and REHAU uPVC can provide better value for years to come.
One of the biggest mistakes homeowners make is comparing installers based only on price. The quality of the window system itself has a significant impact on energy efficiency, security, durability, and appearance.
A reputable double glazing company in London should work with recognised European manufacturers that have built a reputation for quality and innovation. Two of the most respected names in the industry are Cortizo and REHAU.
Cortizo is one of Europe’s leading aluminium system manufacturers, known for producing slim, modern glazing solutions that combine outstanding aesthetics with exceptional performance.
Cortizo aluminium windows and doors offer:
Whether you’re installing aluminium sliding doors, bifold doors, or casement windows, Cortizo systems deliver premium performance while maximising natural light.
For homeowners looking for outstanding thermal efficiency and excellent value, REHAU remains one of the UK’s most trusted uPVC profile manufacturers.
REHAU windows provide:
Their versatility makes them suitable for everything from traditional London terraces to contemporary developments.
Choosing a company that installs recognised systems such as Cortizo and REHAU gives you confidence that you’re investing in products designed to perform for decades.
It’s natural to compare quotations, but choosing the cheapest installer can often become the most expensive decision in the long run.
Low-cost quotes sometimes exclude important elements such as premium hardware, professional finishing, waste removal, insurance-backed guarantees, or energy-efficient glazing. Some installers also use lower-grade window profiles that may warp, discolour, or lose performance over time.
Any reputable double glazing installer in London should comply with current UK Building Regulations and hold recognised industry certifications.
FENSA registration demonstrates that installations meet required standards for energy efficiency, ventilation, and safety. It also provides homeowners with certification that may be required when selling their property in the future.
In addition to certification, ask whether the company provides insurance-backed guarantees and whether its installation teams receive ongoing product training.
Professional accreditation is a strong indication that the installer values quality, compliance, and customer confidence.
No two London properties are the same. A Victorian terrace, Georgian townhouse, warehouse conversion, and new-build apartment all require different glazing solutions.
A professional glazing company should offer bespoke products rather than relying solely on standard sizes.
Whether you need:
your installer should manufacture or supply products tailored to your property’s design, measurements, and performance requirements.
Premium bespoke glazing not only improves appearance but also maximises thermal efficiency, security, and natural light.
Replacing worn or damaged uPVC window handles may seem like a simple task, but selecting the correct replacement is essential for ensuring security, smooth operation, and a perfect fit. With several styles of double glazed window handles, varying spindle lengths, and different locking mechanisms available, choosing the wrong handle can lead to installation issues and reduced window performance.
At NexGlazing, we specialise in high-quality windows and doors, helping homeowners across the UK find the right replacement handles for uPVC, aluminium, and double glazed windows. This guide explains the different handle types, how to measure them correctly, and what to consider before purchasing a replacement.
Espag handles are the most widely used option on modern uPVC double glazed windows. They operate a multi-point locking system through a square spindle that fits into the window lock.
Key features include:
Cockspur handles are commonly found on older uPVC and aluminium windows. Instead of using a spindle, they lock by hooking onto a wedge block fitted to the frame.
Their main characteristics include:
Tilt and turn windows require specially designed handles that allow the sash to tilt inward for ventilation or open fully for cleaning and emergency access.
These handles typically feature:
Cockspag handles combine the design of traditional Cockspur handles with the spindle operation of Espag handles.
They:
Whether you’re looking for replacement uPVC window handles, aluminium window handles, or stylish chrome double glazed window handles, selecting the correct type is the first step.
The spindle is the square metal bar extending from the back of the handle into the locking mechanism.
For Cockspur handles, measure the distance between the handle base and the underside of the spur.
Using the wrong step height can prevent the window from locking correctly.
Measure the distance between the fixing screws.
Some window handles are handed depending on their opening direction.
Replacement window handles are available in several finishes, including:
Choose a finish that complements your existing windows and interior décor.
Replacing your window handles can improve both security and usability. Consider upgrading if:
Many homeowners assume all uPVC window handles are identical, but differences in spindle length, locking mechanisms, fixing centres, and compatibility make choosing the correct replacement essential.
Modern locking handles offer improved security, smoother operation, and better durability, making them an excellent investment for family homes.
At NexGlazing, we help homeowners identify the correct replacement handle and ensure it matches their existing window system for a hassle-free installation.
Espag handles use a spindle to operate a multi-point locking system, offering greater security and weather resistance. Cockspur handles lock using a hooked spur that clamps onto a wedge block and are commonly found on older windows.
Remove the existing handle and measure from the base of the handle to the tip of the spindle. Most uPVC window handles use spindle lengths ranging from 15mm to 40mm, although longer versions are also available.
No. Cockspur and Espag handles use completely different locking systems. To change from one style to another, the internal window locking mechanism would also need to be replaced. For the easiest installation, always choose a direct replacement.
Whether you’re replacing a damaged handle or upgrading your windows with modern locking hardware, choosing the correct uPVC window handle ensures reliable performance, enhanced security, and long-lasting durability.
At NexGlazing, we supply premium uPVC windows, aluminium windows, replacement hardware, and expert glazing solutions tailored to your home. If you’re unsure which handle is right for your windows, our experienced team is here to help you find the perfect fit.
