Sweden Adds Biometric HVAC Adjustment in High-Speed Trains

Post by : Amit

Sweden Pioneers Biometric Climate Control in High-Speed Rail

In a major leap for passenger comfort and intelligent transport systems, Sweden has become the first country in Europe to deploy biometric HVAC adjustment in its high-speed train fleet. Using facial temperature mapping and occupancy analytics, the system adapts the cabin environment in real-time—without requiring passengers to touch a button or speak a word.

The innovation was launched this week on select routes of the SJ X3000 series, operated by Sweden's national rail company SJ AB, linking Stockholm, Gothenburg, and Malmö at speeds of up to 200 km/h. The project is the result of a three-year collaboration between Ericsson Mobility Systems, KTH Royal Institute of Technology, and ClimateIQ, a Stockholm-based AI startup focused on thermal automation.

A Non-Invasive Climate Control Experience

The core feature is a contactless biometric scanner discreetly integrated above doorways and along window panels in first- and second-class cars. These devices read micro-thermal changes in passengers’ faces and hands, using long-wave infrared sensors that map surface temperatures at over 10 frames per second. Combined with environmental sensors and travel data, the system determines whether a cabin needs more cooling, less airflow, or localized adjustments to prevent cold spots.

As soon as a passenger boards, their thermal profile is anonymously captured, encrypted, and processed through an onboard AI module. Without storing personal data or images, the system reacts dynamically—lowering ventilation when cabins are sparsely occupied or boosting airflow when it senses thermal discomfort during peak loads.

The experience is seamless. Riders feel no air bursts or sudden temperature changes. Instead, there's a gradual thermal drift, keeping the ambient experience consistently within 22–24°C. Importantly, the system adapts to Scandinavian seasonal swings, where morning trains can start at -10°C and reach 22°C inside within an hour due to solar gain and crowding.

Rethinking HVAC with Passenger Biometrics

According to SJ AB’s technology chief Lars Nyström, the biometric HVAC project is not just about luxury—it’s a necessary evolution in energy optimization.

“Traditional HVAC systems treat the cabin like a box with knobs,” Nyström said during the launch in Stockholm Central Station. “But humans aren’t boxes. We radiate heat differently. Our train cars now recognize those differences and adjust faster than any manual system ever could.”

Each X3000 train fitted with the new system is expected to save up to 18% in HVAC-related energy consumption annually, amounting to more than 11 MWh per train. That energy reduction not only lowers emissions for Sweden’s renewable-heavy grid but also frees up battery reserves used in onboard Wi-Fi, infotainment, and braking recovery.

The hardware includes solid-state fans, dynamic airflow ducts, and phase-change filtration units that reduce allergens and humidity. Filters are automatically cleaned at terminal stations, and airflow is modulated to reduce spread of pathogens—crucial in the post-pandemic travel landscape.

Privacy-First Design Meets Nordic Standards

Sweden’s implementation of facial recognition for climate control might sound intrusive, but it’s fully aligned with GDPR and Swedish Data Protection Authority (IMY) standards. The system doesn’t store faces, names, or even consistent profiles. Instead, it reads anonymous temperature zones, much like how thermal cameras screen for fevers in airports.

Passengers are informed via digital signage and ticketing notices. Those wishing to opt out can activate “Manual Mode” on the SJ app or from onboard touchscreens, allowing them to revert to fixed HVAC settings.

The biometric readings also enable inclusive climate zones for children, elderly passengers, and those with medical sensitivity to heat or cold. Special seating zones adjust according to preset temperature ranges, while AI maintains balance across the train.

KTH’s team conducted extensive trials with diverse demographic groups, including individuals with sensory sensitivities, to ensure that the system provides thermal equity and avoids bias in detection.

Smart Rail as a National Sustainability Strategy

Sweden has been aggressively decarbonizing its transport systems. While rail is already one of the cleanest modes of travel, passenger experience and energy efficiency remain national priorities. The government-backed program “Green Rail 2030” targets full electrification, predictive maintenance, and AI integration across its regional and long-distance rail networks.

The biometric HVAC program is co-funded by Sweden’s Vinnova Innovation Agency, under its Mobility-as-a-Service Climate Adaptation Fund, and forms part of the European Union's Horizon 2025 railtech initiative.

ClimateIQ CEO Anna Holmgren sees this as a defining moment for transport comfort design. “We’ve built cars that talk, planes that glide autonomously, and HVACs that respond to air chemistry. But trains still ran on preset climate loops. This changes that.”

Holmgren said the technology can be adapted for metro networks, electric buses, and even airports, offering a universal interface between human thermal behavior and automated climate systems.

Passenger Feedback: Warmer Response, Cooler Cabins

SJ AB began A/B testing the system on limited coaches in early 2024. During that time, more than 46,000 passengers rode on biometric HVAC trains, with over 88% reporting a noticeable improvement in comfort.

“I didn’t even know it was scanning me,” said Johanna Eriksson, a frequent commuter on the Gothenburg route. “But I usually need to bring a scarf on morning trains because of cold air—this time I didn’t touch my bag once. It just felt... right.”

The lack of direct interaction has proved to be a strength. Older passengers, often hesitant about using digital apps or controls, now benefit from adaptive comfort without the tech friction.

For business travelers working on laptops or using video calls, the biometric system reduces cabin noise—eliminating loud HVAC surges that once disrupted focus or caused discomfort during long journeys.

Manufacturing and Technical Supply Chain

All hardware components were developed and manufactured within the EU. The facial thermographic modules were supplied by FLIR Systems in collaboration with SensAirTech, a Gothenburg-based startup focusing on biometric data fusion. Integration was carried out by Ericsson Mobility Systems, leveraging its edge computing platform used in autonomous mining and seaport vehicles.

The HVAC ducts and dynamic diffusers are made from 100% recycled aluminum and polymer composites, designed to reduce vibration and weight while maintaining airflow resilience at high speeds. Maintenance crews received dedicated training, and the AI software updates are transmitted wirelessly during overnight depot stops.

Each system is modular, enabling retrofits in older X2000 and Bombardier Regina coaches, which SJ plans to upgrade starting in Q2 2026. Finland and the Netherlands have already requested demos for potential deployment on their high-speed and regional rail lines.

The Future: AI, Emotion Detection & Environmental Balance

Beyond temperature, the next phase involves emotional biometrics—detecting discomfort via micro-expressions like frowns, flushed skin, or stress-based perspiration. “We’re researching how emotions influence thermal sensation,” said Holmgren. “If you're nervous before an interview, your perceived heat changes. That has implications for climate tuning.”

Also under development is a dynamic group comfort model, where the AI negotiates preferences across multiple passengers, such as balancing the needs of families, solo travelers, and seniors.

Holmgren’s team is testing this AI on long-haul night trains, where sleepers demand synchronized HVAC modulation for uninterrupted rest. “Imagine a train where everyone wakes up refreshed—not sweaty, not dry-throated. Just... aligned,” she said.

A Cool Path Forward

As global rail networks modernize under the pressure of climate goals, passenger expectations, and digital transformation, Sweden’s biometric HVAC rollout offers a remarkable case of human-centered automation. It blends the tactile comfort of physical space with the responsiveness of smart systems, without requiring passengers to compromise on privacy or agency.

The face of public transport, quite literally, just got smarter—and cooler.

Sweden, Biometric, High-Speed Rail, HVAC