Glass in architecture is increasingly performing more than a single function. Twenty years ago, a good IGU meant three panes and argon fill. Today, that is just the starting point, not the final answer. Facade glass in 2026 can self-clean in the rain, kill bacteria on contact, change transparency on command from a smart home system, generate electricity, provide thermal resistance equivalent to a concrete wall at just 10 millimeters thick, or transmit visible light while completely blocking infrared heat.
For aluminum facade systems — curtain walls, rainscreen facades, structural glazing — this means a fundamental increase in design complexity. An IGU is no longer selected from a catalog; it requires precise coordination of optical properties, thermal performance, acoustics, sealant compatibility with specific coatings, weight loads on the load-bearing aluminum profiles, and maintenance protocols throughout the entire service life.
This article provides a systematic review of key technologies: what they are, how they work, where they are applied, and what limitations must be considered.
Vacuum Insulated Glazing
VIG Construction
Vacuum Insulated Glazing (VIG) is one of the most radical technologies in the modern glazing industry. The principle is simple to describe but complex to execute: a vacuum with residual pressure on the order of 0.1 Pa (approximately one millionth of atmospheric pressure) is created between two glass panes. At such pressure, gas conduction and convection through the gap are practically zero.
The problem is that atmospheric pressure wants to collapse this structure. To prevent the two glass panes from touching, microscale support pillars with a diameter of 0.3–0.5 mm and a height of about 0.15–0.2 mm are placed between them. These pillars determine two key characteristics of the system: mechanical stability and residual thermal conductivity — because even such a tiny element creates a «thermal bridge» through the vacuum.
Studies have shown that the contact area of the pillar with the glass surface affects thermal conductivity more strongly than its volume. Optimal geometry is not cylindrical but rectangular or specially shaped to minimize contact area while maintaining strength. Switching from metal pillars to glass pillars reduces the U-value by 10–20% — because glass conducts heat less well than metal.
Perimeter sealing is another critical zone. Traditionally, glass frit with a high melting point is used. New technologies — laser sealing — allow creating a thinner, more uniform joint without thermal stress in the adjacent glass.
Technical Characteristics and Applications
A finished VIG unit, at a total thickness of just 6–12 mm, achieves a U-value in the range of 0.3–0.7 W/(m²·K). For comparison, a good triple-glazed IGU with argon and double Low-E coating gives 0.6–0.8 W/(m²·K) at a thickness of 36–44 mm. VIG provides comparable or better performance at one-third the thickness.
This opens applications where VIG has no alternative.
Historic building restoration. Wooden frames of historic buildings have a fixed glazing rebate depth — often only 10–12 mm. Installing a modern triple-glazed IGU is physically impossible. VIG fits into the existing frame and dramatically improves thermal performance.
Thin aluminum facade systems. Where architectural design demands minimal visible profile width and minimal overall IGU thickness, VIG enables high energy efficiency in an ultra-slim construction.
Passive houses and zero-energy buildings. A U-value of 0.3–0.5 W/(m²·K) brings glazing’s thermal insulation close to that of an opaque wall — necessary for certification under the most stringent standards.
Limitations
Mass production of VIG remains technologically challenging. The key manufacturing problem is pillar-induced cracks. A study using neural networks for automated quality control of VIG showed that the typical defect is cone-shaped cracks around pillars, occurring during production, transport, and installation. This is a nontrivial quality control problem — manual inspection of every pillar on each unit is practically impossible.
The cost of VIG is currently 3–5 times higher than a standard IGU. The longevity of properly executed VIG is up to 30 years. Pilot batches that have undergone real-world exposure in various climatic zones show expected characteristics without vacuum degradation. If the hermetic seal fails, the vacuum degrades, and the unit reverts to a conventional air-filled IGU — this is a one-time failure, not gradual degradation.
Hybrid VIG. A promising direction is combining a VIG unit with an additional conventional gas-filled cavity. Such a construction gives an overall Uw of about 0.5–0.8 W/(m²·K) while simultaneously providing high sound insulation (up to 38 dB). This is a compromise between the extreme thermal insulation of pure VIG and a more manufacturable construction.
Aerogel
What Is Aerogel
Aerogel is one of the most remarkable man-made materials. In essence, it is a solid that is 99% air: its porous nanostructure traps air in pores sized 10–20 nm.
The problem with traditional aerogels for glazing applications is optical scattering. Randomly distributed pores scatter light, making the material translucent. This is why aerogel earned the nickname «frozen smoke» — it looks like a semi-transparent haze. This made it suitable for skylights, sports facilities, and canopies where transparency is not critical, but unsuitable for ordinary windows.
Transparent Aerogel: MOCHI
In December 2025, a research group from the University of Colorado Boulder published in the journal Science a description of a new material — MOCHI (Mesoporous Optically Clear Heat Insulator). The key difference from traditional aerogel: the pores are ordered, not randomly arranged, and their size is below the threshold for visible light scattering.
Fabrication process: surfactant molecules are added to a liquid solution, which spontaneously self-assemble into thread-like structures (analogous to oil and water separation in salad dressing). Silica molecules attach to the surface of these threads. After chemical removal of the threads, silica tubes remain, filled with air. The ordered porous structure traps heat without scattering visible light.
Characteristics: transparency greater than 99%, thermal insulating capacity 10 times better than ordinary glass, the material is 90% air. According to the researchers’ calculations, a coating of MOCHI on a standard single-pane window could significantly reduce heat loss.
MOCHI is not yet a commercial product. The manufacturing process has not been scaled up. The researchers note that the base raw materials are relatively inexpensive and the process is potentially optimizable — but that is a task for the coming years.
Aerogel Films
A parallel line of development is aerogel-based films for retrofitting existing windows. A 2025–2026 study describes a transparent film based on aerogel with ITO nanoparticles (indium tin oxide) that blocks the near-infrared portion of the spectrum (the part of solar radiation that heats a room) while transmitting visible light. Compared to single-pane glass, such a film reduces the U-value by 61% and the solar heat gain coefficient by 30%. This solution is for hot climates — convenient because it can be applied to existing windows without replacing the IGU.
Applications in construction today:
- Skylights and light ceilings — where diffuse light (not transparency) is needed; aerogel is already used in semi-transparent panels
- Insulating inserts between facade elements
- Sports facilities with polycarbonate roofs — aerogel granules as filler
Self-Cleaning Glass
Working Mechanism
Self-cleaning glass is based on a coating of ultra-thin titanium dioxide (TiO₂) layer 10–30 nm thick. This coating produces two complementary effects.
Photocatalytic effect. Under UV radiation, TiO₂ absorbs photons and generates highly reactive hydroxyl radicals. These radicals break down organic contaminants — pollen, oils, soot, biofilms — into CO₂ and water. The efficiency of photocatalytic decomposition of organics reaches 85%.
Hydrophilicity. The same UV activation changes the surface energy of TiO₂ so that water does not form droplets but spreads into a thin, uniform film. When it rains (or when a facade irrigation system is activated), water does not run off in drops leaving streaks, but washes away the already decomposed contaminants in an even sheet.
Limitations
The first limitation is dependence on UV. In shaded areas of a building, in regions with cloudy climates, or when UV-blocking IGUs are used, the photocatalytic effect is significantly reduced. The coating does not work in the dark and requires regular natural UV exposure to maintain activity.
The second is water. Washing away decomposed dirt requires water. In dry climates, photocatalysis works, but no rinsing occurs — artificial irrigation is needed.
In 2025, large-format self-cleaning glass panels measuring 3.2 × 6 meters became available — specifically for facade installations on high-rise buildings.
Where It Is Applied
Self-cleaning glass is most in demand where facade cleaning is difficult and expensive: high-rise buildings, glass roofs, atriums, solar panels. For commercial projects, reduced facade maintenance costs are a measurable economic argument. In sunny regions, self-cleaning coatings are also important for photovoltaic panels: a dust layer can reduce energy output by 15–25%.
Antibacterial Glass
Principle of Operation
Antibacterial glass contains a coating with active ions (most often silver or copper) that, upon contact, destroy bacterial cell membranes and inactivate viruses. The active ions are released into the thin surface moisture layer that is always present on any surface.
An additional technology — based on TiO₂ with UV activation — partially overlaps with self-cleaning glass. Under UV exposure, active radicals are generated that break down not only organic dirt but also the cell walls of microorganisms.
Effectiveness: laboratory tests show elimination of up to 99.9% of bacteria (such as Staphylococcus aureus and E. coli) within 2–4 hours. Studies of nanocomposite copper-based coatings confirm that antibacterial properties are maintained after two years of regular wiping.
Applications
Medical facilities are the primary application area. Glass partitions, doors, windows for examination rooms, isolation wards, operating theaters. Antibacterial glass here provides an additional protective layer on top of standard disinfection protocols.
High-traffic public spaces: transport terminals, shopping centers, schools.
It is important to remember that an antibacterial coating reduces the concentration of microorganisms but does not replace disinfection — especially in environments with high microbiological load. It is a supplementary tool, not an alternative to mandated procedures.
Smart Glass: Controllable Transparency
Instant Switching (PDLC)
PDLC (Polymer-Dispersed Liquid Crystal) is a technology where liquid crystals are dispersed in a polymer matrix. In the absence of an electric field, the crystal molecules are randomly oriented — the glass is frosted. When voltage is applied, they align with the field — the glass becomes clear. Switching is instantaneous (fractions of a second). It consumes energy only in the clear state; when power is cut, it returns to frosted.
PDLC is used primarily in interior partitions, conference rooms, medical offices, bathrooms. In the clear state, it provides 70–85% light transmittance. The frosted mode offers full visual privacy. This technology does not control the amount of heat transmitted — only visibility.
Continuous Tinting Control (Electrochromic)
Electrochromic glass changes its optical state when a small DC voltage is applied. Unlike PDLC, it controls not only visibility but also the transmission of solar heat (infrared radiation). Mechanism: ions (usually lithium) are intercalated into an electrochromic layer (most often tungsten oxide WO₃) and alter its optical properties. Switching is slow — from several minutes to half an hour for large areas. Power consumption is minimal and required only during state changes.
In the fully darkened state, modern electrochromic glass blocks over 99% of solar radiation — eliminating overheating and minimizing cooling loads in hot climates. Adaptive control (via light and temperature sensors) can reduce HVAC energy consumption by up to 20%.
However, durability remains the key barrier to widespread adoption. A 2026 patent landscape analysis shows that about 30% of new patents in electrochromic glass are devoted to improving stability — not switching speed or contrast. Cycle life data reveal a «death valley» between 10,000 and 100,000 operating cycles: this is where many systems degrade sooner than expected.
The latest research (2025–2026) demonstrates electrochromic glass with dual-band control — independent regulation of visible light and infrared radiation. This allows maintaining high visible transparency while blocking heat-generating IR — impossible with standard electrochromic systems.
Fire-Resistant Glazing
Fire-resistant glass is mandatory for high-rise buildings, evacuation routes, atriums, and facade fire-break sections. Several fundamentally different technologies exist.
Intumescent interlayer. A transparent gel (silicic acid hydrate or a special composition) is placed between two glass panes. When heated, the gel foams and turns into an opaque, thermally insulating barrier. The glass on the fire side may shatter, but the foamed gel keeps the structure intact and prevents through-heating. Provides fire resistance ratings from EI 30 to EI 120 and higher.
Tempered fire-resistant glass (type E — integrity only, no thermal insulation). It withstands flame exposure without breaking and blocks combustion products — but does not provide thermal insulation.
Conclusion
Most of the described technologies have already left the laboratory stage and are available as commercial products. Glass is no longer a passive transparent wall but an active element of the building management system.
For aluminum systems, this means the need to think of the facade as an integrated system — from thermal calculations to electrical wiring, from sealant compatibility to maintenance logic. The earlier these issues are addressed in the design, the less painful the solutions become during installation.
