Double glazing uses two panes of glass separated by an insulating chamber, typically filled with argon gas. If that sounds familiar, it's because double glazing has been the UK standard for decades. But if your windows were installed more than 15 to 20 years ago, the technology inside them bears little resemblance to what's available today.
Early double glazed units used basic air-filled gaps and standard glass. Modern sealed units are a different product entirely. Low-emissivity (Low-E) coated glass reflects heat back into the room, warm edge spacer bars virtually eliminate condensation around the frame, and argon gas filling slows heat transfer far more effectively than air alone. The best double glazed windows now achieve U-values as low as 1.2 W/m²K, with energy ratings from A to A++, a level of performance that older double glazing simply cannot match.
If you're noticing draughts, misting between the panes, rising energy bills, or condensation on the inside of your windows, these are signs that your current double glazing has reached the end of its effective lifespan. Replacing it with modern sealed units delivers an immediate improvement in warmth, comfort, and energy efficiency, and can also increase the value of your property. For homes in exposed or high-traffic locations, you may also want to consider our triple glazed windows for even greater performance.
Cristal Windows has been installing high-performance double glazed windows across the region for over 40 years. Our experienced installation teams are directly employed (never subcontracted), FENSA registered, and backed by comprehensive guarantees you can trust.
Double glazing is available throughout our complete window range. Choose from casement, sliding sash, bay and bow, tilt and turn, or flush casement styles in uPVC, aluminium, or timber frames. All styles come with extensive colour and finish options to perfectly match your property.
The cost of double glazed windows depends on the style, frame material, size, and number of windows you need. Our detailed guides break down pricing so you know what to expect before requesting a quote.
Find out what affects your double glazing price and how to budget for your project.
Double glazing is available across every window style we offer, from traditional sliding sash and heritage flush casement to modern tilt and turn and architectural bay and bow designs.
Our double glazed flush casement windows sit perfectly flat within the frame, creating a clean, streamlined appearance that suits both modern homes and conservation areas across Hampshire, Berkshire, and Surrey. With multi-point locking and energy efficient sealed units as standard, flush casements combine heritage charm with contemporary performance.
Double glazed tilt and turn windows offer two opening positions for maximum versatility. Tilt inward from the top for secure ventilation, or turn fully for easy cleaning and wide airflow. Ideal for upper floors and hard to reach areas, they are available in uPVC and aluminium frames with a wide choice of colours and finishes.
Our double glazed aluminium windows feature slim, strong frames that maximise the glass area and flood your rooms with natural light. Thermally broken profiles deliver excellent energy performance while the inherent strength of aluminium provides enhanced security. A premium, contemporary option built to last.
If your home still has single glazed windows or older double glazing from the 1980s and 1990s, security is likely one of your biggest concerns. Older windows often feature basic cockspur handles, single-point locks, and externally beaded glass that can be removed from outside, all of which fall well below modern security standards.
Replacing them with today's double glazed windows is one of the most effective security upgrades you can make to your property. Every Cristal Windows installation includes multi-point locking systems, internally beaded sealed units (the glass can only be removed from inside your home), reinforced frames, and toughened or laminated glass options. All our installations meet current Building Regulations for security and can achieve Secured by Design specifications when required.
One of the first things homeowners notice after upgrading to new double glazing is how much quieter their home becomes. The sealed air gap between two panes of glass acts as an acoustic barrier, noticeably reducing traffic noise, neighbourhood disturbance, and general outdoor sounds. If your current windows have misted units or broken seals, their noise reduction ability will have deteriorated significantly.
This makes double glazing a practical upgrade for homes near busy roads like the A331 and M3, railway lines, or under flight paths such as Farnborough. For properties in particularly high-noise locations, we also offer [triple glazed windows] for even greater sound insulation.
Interested in enhanced security, noise reduction, and energy efficiency? Use our online quotation tool or call 01252 810 777 for personalized advice. We offer free surveys throughout Hampshire, Berkshire, and Surrey.
Double glazing is available in uPVC, timber, and aluminium frames, each offering distinct advantages. The right choice depends on your property style, budget, maintenance preferences, and performance priorities. All three materials deliver excellent energy efficiency with double glazed sealed units, but they differ in appearance, durability, and cost.
uPVC is the most popular frame material for double glazed windows in the UK, and for good reason. It delivers the best balance of energy efficiency, security, and value, making it the natural choice for homeowners across Hampshire, Berkshire, and Surrey looking to upgrade older windows.
If your home still has the original uPVC windows from the 1990s or early 2000s, you may notice draughts, condensation between the panes, or difficulty opening and closing. Today's uPVC frames are a significant step forward. Multi-chambered profiles, reinforced steel cores, and advanced sealed units mean modern double glazed uPVC windows outperform older versions in every measurable way, from thermal efficiency and acoustic insulation to security and longevity.
Available in white, woodgrain finishes, and contemporary colours including anthracite grey, chartwell green, and black, modern uPVC suits everything from Victorian terraces to new builds. With a lifespan of 25 to 35 years and virtually no maintenance beyond an occasional wipe down, uPVC remains the smart, cost-effective option for most properties.
Best for: Homeowners replacing older windows who want proven performance, low maintenance, and excellent value.
For period homes, listed buildings, and conservation areas across Hampshire, Berkshire, and Surrey, timber windows are often the only approved option. If your property falls within a conservation area in places like Farnham, Odiham, or Hartley Wintney, planning regulations may require like-for-like timber replacements that preserve the original character of your home.
Modern timber double glazed windows are engineered very differently from the originals they replace. Factory-applied micro-porous coatings, engineered hardwoods and softwoods, and precision-sealed double glazed units mean today's timber frames last significantly longer and perform far better than the single glazed windows they typically replace. You get the authentic appearance that planning authorities require, combined with the energy efficiency, security, and noise reduction of modern double glazing.
Timber does require more care than uPVC or aluminium. Expect to repaint or restain every 5 to 8 years to maintain protection against moisture and weathering. For homeowners who love the timber look but want a lower maintenance alternative, our flush casement uPVC windows replicate traditional timber aesthetics with modern woodgrain finishes that are virtually indistinguishable from real wood.
Best for: Conservation areas, listed buildings, and period properties where planning requirements or personal preference demand authentic timber craftsmanship.
Aluminium double glazed windows have become increasingly popular across Hampshire, Berkshire, and Surrey, particularly for extensions, new builds, and homeowners updating the look of their property. The slim frame profiles create a contemporary aesthetic that uPVC simply cannot match, with more glass area and cleaner sightlines that let the maximum amount of natural light into your home.
A common misconception is that aluminium frames are poor insulators. While that was true of older aluminium windows, modern frames incorporate thermally broken profiles with insulating barriers built into the frame itself. This means today's aluminium double glazed windows achieve energy ratings comparable to uPVC, while offering superior strength, durability, and a lifespan of 40 years or more. The powder-coated finish is available in virtually any RAL colour, won't peel or fade, and needs nothing more than an occasional wipe to stay looking new.
Aluminium is also the go-to choice when you need larger window openings. Its inherent strength means frames can span wider areas without the bulkier profiles required by uPVC, making it ideal for feature windows, full-height glazing, and seamless connections between indoor and outdoor living spaces. If you're considering aluminium for doors as well, take a look at our aluminium bifold doors and aluminium patio doors for a consistent finish throughout your home.
Best for: Modern properties, extensions, large format glazing, and homeowners who want the slimmest frames with maximum glass area.
High-quality double glazing and triple glazing, expert craftsmanship, and a stress-free experience - trusted by homeowners for over 40 years.
Cristal Windows holds accreditations from FENSA and other industry leaders, ensuring top-tier quality, safety, and reliability.
With 40+ years of experience, we use high-quality uPVC, timber, and aluminium to create durable and stylish windows & doors.
As a family-run business, we focus on guiding you to the best solution—no pushy sales, just expert support.
Find quick answers to common questions about our double glazed windows, including costs, energy savings, replacement signs, and choosing the right options for your home.
Look for condensation between the panes (a failed seal), draughts around the frames, difficulty opening or closing, visible damage, or increased outside noise. If your windows were installed before 2002, they likely fall below current energy efficiency standards and could benefit from upgrading.
Costs vary depending on window style, frame material, size, and the number of windows. For a detailed breakdown, read our guide on how double glazing prices are calculated.
Most homes can be fully fitted within one to three days depending on the number of windows. Each window typically takes between one and two hours to remove and replace. Read our full guide on how long it takes to install new double glazed windows and doors.
Yes. Modern A-rated double glazed windows can significantly reduce heat loss compared to single glazing or older double glazed units. Our guide explains how much double glazing really saves on energy bills in the UK.
In most cases, no. Replacing windows on a like-for-like basis is permitted development. However, if your property is in a conservation area or is a listed building, you may need approval from your local planning authority. Our team can advise on requirements in your area.
These ratings indicate how well a window retains heat. A++ is the highest rating, meaning the least heat loss. The rating is determined by the combination of glass, gas fill, spacer bars, and frame material. All Cristal Windows products are available with A-rated sealed units as standard, with A+ and A++ upgrades available.
Absolutely. Many homeowners replace windows in stages, starting with the most exposed or worst-performing rooms first. We can survey your property and recommend a priority order based on condition and potential energy savings.
All Cristal Windows installations come with a comprehensive guarantee covering both the product and installation. As a FENSA registered company, every installation is also automatically certified for Building Regulations compliance and backed by an insurance-backed warranty.
Double glazing suits most homes and offers excellent energy efficiency, security, and noise reduction at a lower price point than triple glazing. For homes in high-noise or exposed locations, triple glazing provides additional performance. Read our full triple glazing vs double glazing comparison.
Yes. We manufacture all windows to measure and offer a wide range of styles, colours, woodgrain finishes, and hardware options. Whether you need Georgian bars, leaded lights, or a specific RAL colour, we can replicate or complement your existing windows.
Cristal Windows is accredited by FENSA, Which? Trusted Trader, GGF (Glass and Glazing Federation) and other leading industry bodies, ensuring top-tier quality, safety, and reliability for every installation.
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We offer expert installation of high-quality triple and double glazed windows, doors, bi-fold doors, patio doors, composite doors, conservatories, and roof lanterns. If your home is located outside of the areas we typically cover, feel free to give us a call—we’re happy to discuss availability and may still be able to arrange an installation in your area.
When you choose Cristal Windows for your local double glazing and triple glazing installations, you are not only choosing an ethical, professional and family run business, but also a window company that provides high-quality products. We take the utmost care when installing our range of windows, doors, and conservatories and are accredited by trustworthy schemes such as FENSA.
We offer installations to homeowners in Berkshire, Hampshire, or Surrey.