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Guardian SunGuard™ Glass Replacement & Low-E IGU Service
WindowFixGuru™ provides independent glass replacement service for windows, doors, storefronts, and architectural glazing that use Guardian Glass products, including SunGuard™ low-E and solar-control coated glass. Guardian and SunGuard identify the glass and coating technology—not the complete window manufacturer.
If an insulated glass unit becomes foggy, cracked, broken, or loses its seal, the complete window or door does not automatically need replacement. When the frame and sash remain serviceable, the failed glass unit can often be measured, specified, fabricated, and replaced.
We service windows from leading manufacturers
Guardian Glass and SunGuard™: What the Name Means
Guardian Glass manufactures architectural and residential glass products. SunGuard™ is Guardian's architectural coated-glass family designed to provide different combinations of solar control, visible light transmission, thermal performance, reflectivity, and appearance.
A SunGuard marking does not identify the window brand. The surrounding window, door, curtain wall, or storefront may have been manufactured or fabricated by another company using Guardian coated glass.
Get an EstimateSunGuard™ Is Primarily a Glass & Coating Page
Guardian SunGuard is relevant when the repair problem is the glazing itself: failed insulated glass, cracked or broken glass, Low-E coating identification, solar-control performance, safety glass, or matching an existing architectural appearance.
Foggy SunGuard™ Insulated Glass Replacement
Fog, haze, moisture, or mineral deposits between panes usually indicate that the insulating glass seal has failed. Once moisture is inside the sealed cavity, cleaning the exposed surfaces does not restore the original sealed unit.
When the sash, frame, glazing pocket, and surrounding construction remain serviceable, WindowFixGuru™ can evaluate replacement of the insulated glass unit rather than replacement of the complete window.
Get an EstimateBroken & Cracked Guardian Glass
Cracked or broken coated glass can often be replaced at the glass-unit level. Correct replacement requires more than matching width and height. Glass thickness, coating, coating surface, tint or substrate, heat treatment, lamination, spacer, cavity, gas fill, safety requirements, and overall IGU thickness can affect compatibility.
WindowFixGuru™ measures the existing opening and evaluates the original glazing system before replacement glass is ordered.
Low-E Coating Identification
Low-E coatings are engineered to reduce radiant heat transfer. Guardian explains that solar-control coatings can reflect and absorb portions of incoming solar energy, while low-E coatings are designed to reduce longwave radiant heat transfer through the glazing assembly.
For replacement work, identifying that glass is Low-E is only the first step. Different SunGuard products have different visible-light transmission, solar heat gain, reflectivity, color, coating technology, and recommended fabrication configurations.
SunGuard™ SNX Triple-Silver Glass
Guardian's current SunGuard portfolio includes high-performance SNX triple-silver coatings. Examples include SNX 70+, SNX 60+, SNX 62/27, and SNX 51/23. These products are designed to combine natural light with strong solar control.
When replacing glass in an existing façade or window group, the exact product matters because a different coating can create a visible mismatch in color, reflectivity, and light transmission even if the dimensions are identical.
SunGuard™ SNX 62/27
Guardian identifies SNX 62/27 as a triple-silver solar-control low-E product. In Guardian's published clear double-glazed example, it provides high visible-light transmission with low solar heat gain.
For service work, published performance values should not be treated as the performance of every installed unit. Glass thickness, substrate, cavity, gas, coating position, heat treatment, and the rest of the glazing make-up can change final performance.
SunGuard™ SNX 51/23
SNX 51/23 is another current Guardian triple-silver product designed to balance visible light and solar-energy control. It can be relevant on commercial façades, large windows, and other projects where solar performance and appearance are both important.
If only one failed lite or IGU is being replaced within a larger elevation, visual matching should be considered before fabrication.
SunGuard™ SNX 60+ & SNX 70+
Guardian's current SunGuard family also includes SNX 60+ and SNX 70+. These are high-performance coated-glass products intended to provide strong solar control while maintaining substantial daylight.
SunGuard product names should be verified from project records, glass identification, fabricator information, or professional analysis where possible. Do not guess the coating from appearance alone.
SunGuard™ SN 68
Guardian describes SunGuard SN 68 as a double-silver low-E coating with a neutral appearance and balanced thermal performance. Guardian lists commercial and residential applications including large framed windows, storefronts, façades, curtain walls, and roof glazing.
For replacement, the objective is not simply to install 'Low-E glass' but to specify a glazing make-up that is appropriate for the existing application and, where important, visually compatible with adjacent glass.
SunGuard™ SNE, SNR & HP Products
The broader SunGuard portfolio includes SNE, SNR, and HP coated-glass products with different combinations of light transmission, reflectivity, solar control, color, and thermal performance.
This variety is why a generic Low-E replacement can be inappropriate on architectural glazing. The existing product or target performance should be identified as accurately as practical before ordering.
Discontinued SunGuard™ Products
Some older SunGuard products have been discontinued. Guardian's current website, for example, identifies SunGuard SN 54 as discontinued.
A discontinued coating does not automatically mean the complete window system must be replaced. A current or otherwise available glazing option may be evaluated for performance and appearance, but exact equivalence should not be promised without supporting technical data.
SunGuard® IS 20 Interior-Surface Coating
Guardian also offers SunGuard® IS 20, an interior-surface thermal-insulation coating designed for use on the inside surface of double- or triple-glazed units. It is a specialized coating and should not be treated as interchangeable with the solar-control coating on another glass surface.
Coating location matters. The glass make-up and surface numbering should be confirmed when specifying a replacement IGU.
Coating Surface & IGU Configuration
In a double- or triple-pane insulating glass unit, each glass surface has a numbered position. The performance and durability of a coated product can depend on which surface receives the coating and whether the coating is enclosed within the sealed cavity or used as an interior-surface coating.
WindowFixGuru™ does not assume coating position from the brand name alone. Replacement specifications should reflect the selected Guardian product, fabricator requirements, and the actual glazing assembly.
Argon, Spacers & Overall IGU Thickness
An insulated glass unit is a system, not just two pieces of glass. Guardian notes that radiation, conduction, and convection all affect heat transfer within an IGU, and that gas fill and spacer design can influence thermal performance.
Replacement work should consider pane thickness, cavity width, spacer, gas fill where specified, coating, overall unit thickness, and glazing-pocket clearance.
Tempered & Heat-Strengthened SunGuard™ Glass
Many architectural applications require heat-treated glass. Guardian lists heat-strengthening and tempering as fabrication options or requirements for various SunGuard products.
Safety and structural requirements depend on the opening and application. A replacement unit should not be downgraded from required tempered or other safety glazing merely to simplify fabrication.
Laminated Glass & Safety Applications
Certain SunGuard products can be incorporated into laminated glazing configurations. Laminated glass may be used for safety, security, acoustic, overhead, hurricane, or other project-specific requirements.
The existing assembly and project requirements should be reviewed before changing laminated glass to a standard monolithic or insulating configuration.
Storefront & Commercial SunGuard™ Glass
SunGuard is widely used in commercial architecture, including storefronts, curtain walls, façades, large framed windows, doors, and roof glazing. A failed commercial lite may be part of a larger elevation where appearance consistency is important.
WindowFixGuru™ can evaluate cracked, broken, or failed insulated commercial glass and coordinate measurement, safety requirements, glass type, and installation conditions.
Large Residential Windows & Doors
SunGuard products can also appear in residential applications, especially large glazed openings, contemporary homes, oversized windows, and doors where solar control and daylight are important.
If the surrounding frame and hardware remain serviceable, glass-only replacement may preserve an expensive window or door system while correcting the failed glazing.
Matching Existing Glass Appearance
Glass matching can be one of the most important issues on coated architectural glazing. Two Low-E products can differ noticeably in exterior reflectivity, interior reflectivity, transmitted color, reflected color, and visible-light transmission.
When a single lite is replaced next to older glass, age, orientation, lighting, substrate, heat treatment, coating batch, and the original product can all affect visual appearance. Exact invisible matching should not be promised.
Glass Identification & Project Records
Useful identification information can include corner etching, spacer markings, labels, original project specifications, invoices, architectural glass schedules, fabricator records, window-manufacturer documentation, and photos showing the glass next to adjacent units.
For commercial projects, the original glass schedule or glazing specification can be especially valuable because it may identify the precise SunGuard product, substrate, thickness, heat treatment, coating surface, and IGU make-up.
Do Not Diagnose the Coating by Color Alone
SunGuard products are offered in multiple appearances and can be combined with different substrates. Lighting conditions, sky reflection, viewing angle, interior darkness, heat treatment, and adjacent materials can change perceived color.
Color can be a clue, but it should not be the sole basis for ordering expensive replacement glass.
Glass Replacement vs. Complete Window Replacement
If the frame, sash, glazing pocket, and hardware remain structurally serviceable, foggy or broken Guardian SunGuard glass is often a glass problem rather than a complete-window problem.
Complete replacement becomes more appropriate when the surrounding window or door has structural failure, severe frame deterioration, failed glazing pockets, major water intrusion, or other conditions that make glass-only replacement impractical.
Explore Our Services to Repair, Maintain, and Improve Your Existing Windows and Doors
Window Maintenance
Professional window maintenance keeps windows operating smoothly, prevents costly problems, improves energy efficiency, and extends the lifespan of existing systems.
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Hardware Maintenance & Replacement
Professional maintenance and replacement for door handles, locks, hinges, closers, and hardware to improve security, performance, reliability, and everyday operation.
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Historical Window Repair & Maintenance
Specialized historical window repair preserves original character, restores proper operation, improves performance, and maintains the architectural integrity of older properties.
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Interior/Exterior Door Repair & Adjustments
Professional interior and exterior door repair and adjustments to correct sticking, sagging, misalignment, drafts, locking problems, and difficult everyday operation.
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Rotten Wood Repair & Replacement
Rotten wood repair restores damaged frames, sashes, sills, and trim while preserving usable components and preventing further serious structural deterioration.
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Storm Door Repair & Maintenance
Complete storm door repair and maintenance for hinges, closers, handles, screens, alignment, and seals to restore dependable operation and lasting results.
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Low-E Glass Upgrade
Low-E glass upgrades improve insulation, reduce heat transfer, block harmful UV rays, increase comfort, and enhance year-round window energy efficiency.
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Patio Door Repair & Maintenance
Reliable patio door repair and maintenance for rollers, tracks, locks, handles, alignment, and seals to improve smooth operation and overall reliability.
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Screen Repair & Replacement
Screen repair and replacement restores airflow, visibility, and protection from insects using durable materials fitted accurately to windows and doors.
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Commercial Window Service & Repair
Commercial window service keeps business properties secure, functional, and efficient through professional repairs, maintenance, and inspections.
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Window Installation
Professional window installation ensures proper fit, sealing, operation, and energy performance while improving comfort, durability, and overall property value.
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Interior/Exterior Door Installation
Professional interior and exterior door installation with precise fitting, proper alignment, secure hardware, effective sealing, smooth operation, and attractive results.
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Glass Replacement
Restore safety, clarity, comfort, and energy efficiency with professional service for damaged, cracked, foggy, or broken window and door glass.
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Glass Replacement
Whenever practical, we replace only the damaged or failed glass while preserving the components that are still performing properly.
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Screen Repair & Replacement
Our goal is to restore a secure fit, clean appearance, proper airflow, reliable insect protection, and smooth operation.
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Rotten Wood Repair & Replacement
Rotten or water-damaged wood does not always mean your entire window needs to be replaced.
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Complete repair solutions for residential and commercial windows and doors.
Window Services
- Window Adjustment
- Window Recaulking & Sealing
- Window Reglazing
- Sash Repair & Restoration
- Window Mechanism Repair
- Balance Replacement
- Operator Repair
- Lock & Handle Replacement
- Weatherstripping
- Draft Repair
- Foggy Glass Replacement
- IGU Replacement
- Custom Glass Replacement
- Sidelight Glass Replacement
- Sunroom Window Repair
- Greenhouse Glass Repair
- Bay & Bow Window Repair
Door Services
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What People Say
Frequently Asked Questions
Is Guardian SunGuard a window brand?
No. Guardian Glass manufactures glass, and SunGuard™ is a family of coated architectural glass products. The complete window or door may be made by another manufacturer.
Can you replace foggy SunGuard insulated glass?
Often, yes. If the surrounding sash, frame, and glazing system remain serviceable, the failed IGU can often be replaced without replacing the complete window.
Can you replace broken SunGuard glass?
Yes, when a suitable replacement make-up can be specified for the opening, coating, thickness, safety requirements, and glazing system.
Is all SunGuard glass the same?
No. Guardian offers multiple SunGuard coating families with different visible-light transmission, solar control, reflectivity, appearance, and fabrication requirements.
What is SunGuard SNX glass?
SNX products are high-performance triple-silver solar-control low-E coatings in Guardian's SunGuard portfolio.
Can you replace SunGuard SNX 62/27?
Yes, subject to product availability and the required glass make-up. The existing unit and surrounding glass should be identified before fabrication.
Can you replace SunGuard SNX 51/23?
Yes, subject to availability and correct specification. Visual matching can be important when replacing one lite in a larger elevation.
What is SunGuard SN 68?
Guardian describes SN 68 as a double-silver low-E coated glass designed to balance natural light, solar control, and a relatively neutral appearance.
What if my SunGuard coating is discontinued?
A discontinued coating does not automatically require replacement of the whole window. An appropriate current or available alternative can be evaluated, but exact equivalence should not be promised without technical support.
Is SunGuard SN 54 discontinued?
Guardian currently identifies SunGuard SN 54 as discontinued.
What is SunGuard IS 20?
IS 20 is a specialized thermal-insulation coating designed for an interior surface of double- or triple-glazed units.
Can Low-E glass be tempered?
Many coated architectural glass products can or must be heat-treated depending on the product and application. The specific SunGuard product and safety requirements must be checked.
Can SunGuard glass be laminated?
Certain SunGuard products can be used in laminated configurations. The exact product and glazing make-up must be verified.
Why does coating position matter?
Different glass surfaces within an IGU have different exposure and performance roles. The selected coating must be placed on an appropriate surface according to the product and glazing design.
Can you match the color of my existing SunGuard glass?
We can work toward an appropriate visual match, but exact invisible matching cannot always be guaranteed, especially with older or discontinued coatings.
Can I replace SunGuard with any Low-E glass?
Not necessarily. A generic Low-E product may differ significantly in solar heat gain, light transmission, reflectivity, color, coating type, and fabrication requirements.
Can you replace SunGuard glass in a storefront?
Yes. We can evaluate commercial storefront and architectural glass replacement, including safety, thickness, coating, appearance, and installation requirements.
Can you replace SunGuard glass in a residential window or door?
Yes. SunGuard products can be used in residential applications, particularly larger glazed openings. The existing unit must be identified and measured.
Do I need a whole new window if the IGU seal failed?
Not automatically. If the frame and sash remain sound, replacing the failed insulated glass unit is often worth evaluating first.
Are you affiliated with Guardian Glass?
No. WindowFixGuru™ is an independent repair company and is not affiliated with, sponsored by, or an authorized Guardian Glass or SunGuard dealer or service provider unless specifically stated otherwise.
Request Guardian SunGuard™ Glass Replacement
If your Guardian or SunGuard glass is foggy, cracked, broken, visually damaged, or part of an older glazing system that needs identification, contact WindowFixGuru™. Photos of the full opening, glass markings, spacer, labels, adjacent glass, and any original specifications can help determine the correct replacement path.
Call or text WindowFixGuru™: 516-841-5048
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