DOUBLE GLAZED UPVC WINDOW - COMPLETE INSULATED GLASS PRODUCT GUIDE SECTION 1: PRODUCT INTRODUCTION This comprehensive product guide presents our premium double glazed UPVC windows, with a special focus on the insulated glass unit (IGU) technology that lies at the heart of their outstanding performance. Our factory specializes in the production of high-performance double glazed UPVC windows, combining advanced glazing technology with precision-engineered multi-chamber frames to deliver windows that excel in thermal insulation, acoustic performance, condensation control and overall energy efficiency. Double glazing, also known as insulated glazing or dual-pane glazing, is a technology in which two panes of glass are separated by a sealed spacer bar, creating an insulating air gap between them. This construction dramatically reduces heat transfer compared to single glazing, improves sound insulation, and helps prevent condensation. When combined with a high-quality UPVC frame, the result is a window system that significantly improves the comfort, energy efficiency and value of any building. This guide provides an exhaustive examination of our double glazed UPVC windows, covering the construction of insulated glass units, the various glass types and coatings available, the science behind Low-E coatings and gas filling, performance specifications, quality control, selection guidance and frequently asked questions. Whether you are a homeowner seeking to upgrade your windows, a contractor specifying windows for a project, or a developer building energy-efficient properties, this guide is designed to give you complete confidence in our double glazed UPVC windows. The demand for energy-efficient windows has never been higher, driven by rising energy costs, stricter building regulations and growing environmental awareness. Double glazing is now the standard for high-quality windows in most markets, and advanced technologies such as Low-E coatings and inert gas filling have made modern double glazed windows more efficient than ever. Our windows are engineered to deliver these benefits with precision, reliability and long-term performance. SECTION 2: INSULATED GLASS UNIT (IGU) CONSTRUCTION The insulated glass unit is the component that provides the thermal and acoustic performance of a double glazed window. Understanding its construction is key to appreciating the quality and performance of our windows. Two Panes of Glass: A double glazed IGU consists of two panes of glass. Each pane can be selected from a range of glass types depending on the performance requirements and application. The panes are typically 4mm to 6mm thick, although other thicknesses are available for special applications. Spacer Bar: The two panes are separated by a spacer bar that runs around the entire perimeter of the unit. The spacer bar maintains a consistent gap between the panes and creates the sealed insulating cavity. The width of the spacer bar determines the size of the air gap, which typically ranges from 6mm to 20mm. Primary Seal: The spacer bar is bonded to the glass panes with a primary seal, which provides the initial airtight and watertight connection. High-quality primary sealing is essential for the long-term integrity of the unit. Secondary Seal: An additional secondary seal is applied around the edge of the unit to provide structural bonding and further protection against moisture and gas leakage. The secondary seal also contributes to the structural strength of the unit. Desiccant: The spacer bar contains a desiccant material that absorbs moisture from the sealed cavity. This prevents condensation and fogging from forming between the panes, which would otherwise obscure the glass and indicate a failed seal. Sealed Cavity: The sealed cavity between the panes is filled with dry air or, for enhanced performance, an inert gas such as argon or krypton. The cavity provides the insulating layer that reduces heat transfer between the interior and exterior. Edge Sealing: The quality of the edge seal is critical to the long-term performance of the IGU. A properly sealed unit prevents moisture ingress and gas leakage, ensuring that the insulating performance is maintained for many years. SECTION 3: GLASS TYPES EXPLAINED The choice of glass is one of the most important decisions in configuring a double glazed window. We offer a comprehensive range of glass types to meet different performance, safety and aesthetic requirements. Clear Float Glass: This is the standard glass type, offering excellent transparency and light transmission. It is suitable for applications where maximum clarity is desired and provides good basic insulation when used in a double glazed unit. Low-E Coated Glass: Low-E (low emissivity) glass has a microscopic metallic coating that reflects heat. In winter, it reflects heat back into the room, reducing heat loss. In summer, it reflects solar heat, reducing heat gain and keeping the interior cooler. Low-E glass significantly improves the thermal performance of a double glazed unit and is available in different performance grades. Tempered (Toughened) Safety Glass: Tempered glass is heat-treated to increase its strength, making it approximately four to five times stronger than annealed glass of the same thickness. When it breaks, it shatters into small, relatively harmless pieces. Tempered glass is required for safety glass applications and is recommended for ground-floor windows, doors and areas where impact is a risk. Laminated Glass: Laminated glass consists of two or more glass panes bonded together with a tough interlayer, typically polyvinyl butyral (PVB). If the glass breaks, the interlayer holds the fragments in place, preventing shards from scattering and maintaining the structural integrity of the window. Laminated glass provides enhanced safety and security and also offers improved sound insulation and UV protection. Tinted Glass: Tinted glass has a colored tint that reduces solar heat gain and glare. It is available in various colors such as bronze, gray, green and blue. Tinted glass is useful in hot climates to reduce cooling loads and in applications where glare reduction is desired. Acoustic Glass: Acoustic glass is a laminated glass designed specifically to improve sound insulation. It uses a special acoustic PVB interlayer that effectively dampens sound transmission, making it ideal for buildings in noisy environments. Reflective Glass: Reflective glass has a metallic coating that reflects solar radiation, reducing heat gain and glare. It provides a distinctive mirrored appearance and is often used in commercial buildings. SECTION 4: WARM-EDGE SPACER TECHNOLOGY The spacer bar is not just a structural component; it also affects the thermal performance of the IGU, particularly at the edges of the unit where heat loss is greatest. Standard Spacer: Traditional spacers are made from aluminum, which is a good conductor of heat. This creates a "cold edge" at the perimeter of the IGU, where heat can escape more readily, leading to reduced insulation performance and potentially increased condensation. Warm-Edge Spacer: Our premium double glazed windows use warm-edge spacer technology, in which the spacer bar is made from a low-conductivity material or features a thermal break design. This reduces heat transfer at the edge of the unit, improving the overall U-value and reducing the risk of condensation at the edge. Benefits of Warm-Edge Spacers: Warm-edge spacers improve the thermal performance of the window, reduce condensation at the edges, and enhance the overall comfort and energy efficiency of the building. They also contribute to a cleaner, more consistent appearance. Thin-Glass Spacers: Some warm-edge spacer systems are designed for use with thinner glass, allowing for a slimmer overall unit profile while maintaining performance. Selection: Warm-edge spacer technology is standard in our premium double glazed windows and is recommended for applications where maximum thermal performance and minimal condensation are desired. SECTION 5: GAS FILLING FOR ENHANCED INSULATION The insulating cavity of a double glazed unit can be filled with dry air or an inert gas to improve thermal performance. Inert gases are heavier and less conductive than air, providing better insulation. Argon Gas: Argon is the most commonly used gas for filling insulated glass units. It is an inert, non-toxic, colorless and odorless gas that is approximately one-third less thermally conductive than air. Filling the cavity with argon reduces heat transfer through the unit, improving the U-value by approximately 5 to 10 percent compared to air-filled units. Krypton Gas: Krypton is a more expensive inert gas with even lower thermal conductivity than argon. It provides better insulation performance, particularly in units with narrower cavities where argon is less effective. Krypton filling is used in premium and passive house windows. Gas Concentration: For the gas to be effective, the cavity must be sealed with a high concentration of the gas. Our production uses automated gas filling systems that achieve and maintain high gas concentrations, ensuring optimal insulation performance. Gas Retention: The quality of the edge seal is critical to retaining the gas over the life of the unit. A well-sealed unit retains a high percentage of its initial gas charge for many years, maintaining its insulating performance. Gas Fill Indication: Some premium units include a marking or label indicating the gas fill and its specifications. This helps ensure that the correct gas filling is provided. Selection Guidance: We provide guidance on whether argon or krypton filling is appropriate for your application, considering factors such as climate, cavity width and performance requirements. SECTION 6: U-VALUE AND CONDENSATION CONTROL The U-value is the key metric for measuring the thermal performance of a window. Understanding U-value and condensation is essential to selecting the right double glazed window. U-Value Defined: The U-value measures the rate of heat transfer through a building element, in this case the window. A lower U-value indicates better insulation and less heat transfer. U-values are measured in W/m2K (watts per square meter per Kelvin). Window U-Value: The overall U-value of a window system depends on the combined performance of the frame and the glazing. Our double glazed UPVC windows achieve overall U-values ranging from approximately 1.1 W/m2K for standard configurations to below 0.9 W/m2K for premium configurations with Low-E coatings, argon filling and warm-edge spacers. How U-Value is Improved: The U-value is improved through the use of Low-E coatings, gas filling, warm-edge spacers and high-quality multi-chamber frames. Each element reduces heat transfer through the window. Condensation Defined: Condensation occurs when warm, moist indoor air comes into contact with a cold surface, such as a window pane, and the moisture in the air condenses into water droplets. Condensation can lead to mold, dampness and damage to window frames and surrounding areas. How Double Glazing Reduces Condensation: Because the inner pane of a double glazed unit is kept warmer by the insulating cavity, the surface temperature of the inner glass is higher than that of a single pane. This reduces the likelihood of condensation forming on the interior surface of the window. How Low-E and Warm-Edge Help: Low-E coatings and warm-edge spacers further reduce heat loss at the glass and edges, keeping the inner surface warmer and further reducing condensation risk. SECTION 7: LOW-E COATING MECHANISM Low-E (low emissivity) coating is one of the most important technologies in modern energy-efficient windows. Understanding how it works helps you appreciate the value it provides. What Low-E Coating Is: A Low-E coating is a microscopically thin, virtually invisible metallic layer applied to the surface of the glass. It is designed to control the transmission of heat and light through the glass. How It Reflects Heat: The Low-E coating reflects long-wave infrared radiation (heat). In winter, the heat from inside the room is reflected back into the room, reducing heat loss. In summer, the solar heat from outside is reflected away, reducing heat gain. Solar Control: Different grades of Low-E coating provide different balances of heat reflection and light transmission. Some coatings are designed to maximize heat reflection in cold climates, while others are optimized to reduce solar heat gain in warm climates. Low-E Glass in Double Glazing: In a double glazed unit, the Low-E coating is typically applied to the interior surface of one of the panes, where it can most effectively reflect heat back into the room while remaining protected within the sealed unit. UV Protection: Low-E coatings also help reduce the transmission of ultraviolet (UV) radiation, which can fade furniture, flooring and fabrics. This provides additional protection for your interior. Energy Efficiency: By reducing heat loss in winter and heat gain in summer, Low-E glass significantly improves the energy efficiency of the window, reducing heating and cooling costs. SECTION 8: SAFETY AND LAMINATED GLASS OPTIONS Beyond thermal and acoustic performance, the glass in a double glazed window plays an important role in safety and security. We offer safety glass options to meet the requirements of different applications. Tempered Safety Glass: Tempered glass is required by building regulations in many applications, including ground-floor windows, doors and areas where people could come into contact with the glass. It is much stronger than annealed glass and breaks into small, relatively harmless pieces, reducing the risk of injury. Laminated Safety Glass: Laminated glass provides an even higher level of safety and security. The PVB interlayer holds the glass together if it breaks, preventing shards from scattering and reducing the risk of injury. Laminated glass is also more difficult to break through, enhancing security against intruders. Burglary Resistance: For enhanced security, laminated glass can be used in the inner pane of a double glazed unit, making the window more resistant to forced entry. This is recommended for ground-floor windows and other vulnerable areas. Impact Resistance: Laminated glass provides good impact resistance, protecting against accidental impacts and flying debris during storms. Acoustic Benefits: Laminated glass also provides excellent sound insulation, making it a good choice for buildings in noisy environments. SECTION 9: IGU QUALITY CONTROL The long-term performance of a double glazed window depends on the quality of the insulated glass unit. We maintain rigorous quality control to ensure that every unit meets high standards. Clean Production Environment: Our IGU production is carried out in a controlled environment to prevent contamination of the glass and seals, which could compromise the quality of the unit. Automated Processing: We use automated glass cutting, washing, spacer application and sealing equipment to ensure precision and consistency. Desiccant Filling: The spacer bar is filled with the correct amount of desiccant to absorb moisture and maintain a dry cavity. Gas Filling Verification: For gas-filled units, we verify the gas concentration to ensure it meets the specified performance. Visual Inspection: Each unit is inspected for visual quality, including the alignment of the panes, the uniformity of the spacer and the quality of the seals. Dew Point Testing: We perform dew point testing on units to verify that the seal is effective and that condensation will not form between the panes. Dimensional Checks: The overall dimensions of each unit are checked to ensure a correct fit in the frame. Traceability: Each production batch is documented for traceability, supporting quality assurance and after-sales service. SECTION 10: SELECTION GUIDE Selecting the right double glazed window configuration is important to achieve the performance you need. This guide helps you make an informed choice. Determine Performance Requirements: Consider the climate, the orientation of the window, the level of noise in the area, and your energy efficiency goals. These factors will guide your choice of glass and configuration. Choose the Frame System: Select a profile depth and chamber configuration that provides the thermal and structural performance your project requires. Deeper profiles with more chambers generally offer better insulation. Select the Glass Type: Choose the glass type based on your priorities. For energy efficiency, choose Low-E glass. For safety, choose tempered or laminated glass. For sound insulation, choose acoustic laminated glass. Configure the IGU: Specify the glass thickness, air gap width, gas filling and spacer type. A wider air gap and argon or krypton filling improve insulation. Warm-edge spacers reduce edge condensation. Consider the Overall U-Value: Aim for a window U-value that meets your project's energy performance requirements. Lower U-values indicate better insulation. Seek Professional Advice: Our technical team can help you configure the optimal window system for your specific project, considering all relevant factors and balancing performance with cost. SECTION 11: FREQUENTLY ASKED QUESTIONS Q1: What is the difference between argon-filled and air-filled double glazing? A: Argon gas is approximately one-third less thermally conductive than air, so argon-filled units provide better insulation and a lower U-value. Argon is recommended for colder climates and for applications where maximum energy efficiency is desired. Q2: Will condensation form between the panes? A: No. Our sealed units use desiccants in the spacer bar to absorb moisture and prevent condensation from forming between the panes. If condensation does appear between the panes, it indicates a failed seal, which is covered by our warranty. Q3: Which direction does Low-E coating face? A: In a double glazed unit, the Low-E coating is typically applied to the interior surface of the outer pane or the interior surface of the inner pane, depending on the climate and design. Our team configures the coating position correctly for your application to maximize performance. Q4: Is triple glazing worth the extra cost? A: Triple glazing provides even better thermal and acoustic insulation than double glazing and is recommended for very cold climates and passive house projects. Whether it is worth the extra cost depends on your climate, energy costs and performance requirements. Q5: What is the difference between laminated and tempered glass? A: Tempered glass is heat-treated to increase strength and breaks into small, harmless pieces. Laminated glass consists of panes bonded with a tough interlayer that holds the glass together when broken. Laminated glass provides better security and sound insulation, while tempered glass is stronger against direct impact. Q6: What is the dew point of your insulated glass units? A: Our insulated glass units are tested to meet a dew point of -40 degrees Celsius or lower, indicating a high-quality, well-sealed unit that will not fog between the panes. Q7: How long is the IGU warranty? A: We provide a warranty on our insulated glass units covering manufacturing defects and seal integrity. The specific warranty terms depend on the product and are detailed in our warranty documentation. Q8: How can I tell if my IGU seal has failed? A: Signs of a failed seal include condensation or fogging between the panes, which cannot be cleaned from the outside. If this occurs, the unit should be replaced. Our warranty covers premature seal failure. CONCLUSION Our double glazed UPVC windows represent the combination of advanced insulated glass technology and precision-engineered frames, delivering outstanding thermal insulation, acoustic performance, condensation control and energy efficiency. With a wide range of glass options, warm-edge spacers, gas filling and rigorous quality control, our windows are engineered to provide comfort, savings and long-term value. We invite you to contact us to discuss your requirements, request samples or obtain a quotation.