Smart walls
Active and adaptive materials in architecture
Smart walls redefine the role of the architectural envelope, going beyond the simple function of boundary, infill or finishing support.
The wall can become a technical interface capable of regulating light, heat, ventilation, privacy and durability through materials that modify their performance in response to environmental conditions. Variable-transmittance glass, latent heat storage layers, and moisture-sensitive coatings demonstrate how material, geometry, and performance can be integrated without always relying on invasive plant systems.
The main experiments on smart walls mainly concern facades and external envelopes, but the same principles can also be transferred to interior space projects.
From passive wall to reactive surface
A traditional wall is designed to provide separation, insulation, protection, and construction continuity. Smart walls add an additional feature: the ability to modify their behavior over time.
An “active” system responds through power, sensors, or controls, while an “adaptive” system can react directly to environmental stimuli such as temperature, solar radiation or humidity, using physical properties of the material.
This is an essential distinction, which has a significant impact on design. electrochromic glass, for example, requires an electrical signal to vary the degree of coloration. hygromorphic material It can instead deform by absorbing or releasing humidity, without conventional actuators.
In the first case, the project must coordinate power supply, control logic, and maintenance; in the second, it must govern response thresholds, stability, environmental cycles, and long-term behavior.
The smart wall is therefore not a single product, but a complex design system, in which the construction detail becomes decisive.
It's called FlectoLine and it's a dynamic façade capable of changing its shape thanks to a system based on AI and compressed air. Photographs by ITKE/ITFT, University of Stuttgart
Chromogenic materials: light, transparency and visual comfort
Among the most advanced solutions today are chromogenic materials, used mainly in transparent or semi-transparent surfaces to modulate the passage of light and solar radiation.
Electrochromic glass modify the optical properties through an electrical impulse: they can darken to reduce glare and solar load, or become lighter to promote natural lighting and solar gain in cold periods.
Their usefulness does not only concern energy saving, but also the quality of the space. dynamic glass facade It allows you to reduce your dependence on opaque internal screens, lowered curtains and solutions that interrupt the visual relationship with the outside.
SageGlass It is an electrochromic glass of Saint-GobainBy varying the pressure applied to the glass pane, its color can be controlled, thus varying the light intensity and the ultraviolet and infrared radiation transmitted through the material. In other words, this dynamic glass allows building users to actively control natural light and solar heat gain, improving comfort and significantly reducing energy consumption. Dynamic glass tinting is managed by an intelligent control system that uses sensors to automatically tint the glass based on light conditions. Its appearance can also be controlled via smartphone. Importantly, the main advantage is the ability to maintain a view of the outside through the glass.
Alongside the electrochromics there are thermochromic and photochromic materialsThe former vary their behavior as a function of temperature, the latter in relation to the incident light.
These are undoubtedly very promising technologies, but they must be carefully evaluated: the activation threshold, the response speed, the color rendering and the durability of the variation cycle are key design aspects.
The most recent research on spectrally controlled electrochromic glass They demonstrate the potential of solutions capable of managing visible light and solar radiation separately, as they allow for the reduction of incoming heat without automatically transforming the environment into a dark space.
Phase change materials: how the wall accumulates
Phase change materials, known as PCM (Phase Change Materials), instead, introduce a different logic: they do not only shield, but accumulate and release thermal energy.
During the phase change, they absorb heat, while when the temperature drops, they release it. Inserted into panels, plaster, drywall slabs or lightweight stratigraphy, they can increase thermal inertia of elements that would normally be almost devoid of them.
This makes them very interesting in buildings with lightweight structures, in redevelopment projects and in interiors where it is not possible to significantly increase the wall mass.
From a design point of view, however, the PCM should not be interpreted as a universal solution.
It works when the transition temperature it is consistent with the climate profile, the use of the rooms and the ventilation strategy.
However, if the wall accumulates heat but is unable to release it during the night or during favorable periods, the benefit is reduced.
The choice therefore requires reasoning on the daily sequence of heat exchanges: solar exposure, internal loads, ventilation, shading and occupancy times.
The most recent scientific reviews confirm the potential of PCMs in improving comfort and thermal stability, but also indicate the need to evaluate material compatibility, durability, costs and real behavior over time.
Kinetic walls and deforming materials
A particularly relevant development front concerns materials capable of transforming an environmental stimulus into movement.
Le shape memory alloys, such as those based on nickel-titanium, can function simultaneously as a sensor and actuator: when a certain temperature is exceeded, they change configuration and can open slats, panels or micro-openings.
Applied to ventilated facades o solar shading, allow us to imagine self-regulating devices with less dependence on motors, control units and complex mechanical components.
The following are inserted in the same direction: hygromorphic systems, often derived from the behavior of wood and biobased materials, which exploit variations in humidity to generate controlled deformations, producing curvature, torsion or opening of thin elements.
It's not just curiosity biomimetics: the possibility of designing components that react without power opens up interesting scenarios for passive shading, ventilated facades and low-maintenance envelopes.
The difficulty lies in the transition from experimentation to construction detail: a module must be repeatable, replaceable, protected from agents that would compromise its response, and compatible with fixings, tolerances, and safety of use.
Also read: "Equipped walls and functional spaces: when the wall organizes the space"
The smart wall as a complex layered system
Thinking of smart walls as additional external elements to be integrated into an already defined building is a big mistake. The effectiveness of these elements, in fact, arises and develops from coherence between orientation, climate, geometry, stratigraphy and management of internal spaces.
Dynamic glass may be of little use if the building fails to control thermal bridges and side glare. Likewise, PCM may not function properly without ventilation or adequate charging and discharging, while adaptive shading may become illogical if its maintenance is more complex than the problem it is designed to solve.
For this reason the project should start from some technical questionsWhat phenomenon needs to be regulated? Light, heat, humidity, privacy, ventilation, or degradation? Should the response be continuous or seasonal? Is spot control required or an autonomous response? Does the material work best as an exposed, intermediate, or protected layer?
The smart wall takes on design value only when the performance becomes readable in the construction drawing: joints, accessibility, component replacement, compatibility between substrate and cladding, condensation management, fire behaviour and surface ageing cannot be considered secondary aspects.
The role of the designer: between performance, form and maintenance
Today, smart walls are no longer just a matter of experimental research, but equally, they are not yet a standard, fully established solution in building practice.
Some technologies, such as electrochromic glass, are already available on the market; others, such as many hygromorphic solutions or some facades with shape-memory alloys, remain more closely linked to prototypes, case studies, and controlled applications.
This intermediate condition requires a well-researched design approach: understanding the physical principle, verifying its maturity, modeling performance, and predicting maintenance scenarios. Architectural quality arises when the technical response doesn't erase the composition, but rather makes it more precise.
Smart walls therefore require a conscious project, capable of making active and adaptive materials, environmental performance, construction details and quality of space interact within a single perfectly integrated architectural system.
