GreenTEG

What GreenTEG does

GreenTEG (legal entity greenteg AG) is a Swiss thermal sensing company founded in 2009 as a spin-off of ETH Zurich, headquartered in Rümlang near Zurich Airport with 40+ specialists. Its core technology is a patented heat flux sensor platform commercialized under the CALERA® brand, which delivers continuous, non-invasive core body temperature measurement by sensing heat flux at the skin surface rather than requiring ingestible or insertible probes. This sensor is embedded into OEM partner products (Withings ScanWatch, Corsano CardioWatch, Myant Skiin smart textiles, J-style X7 Ring, Thorlabs thermal power sensors), licensed for medical and wearable integrations, and also sold under the company's own consumer brand CORE (CORE, CORE 2, CORE Live) for sports performance and workforce heat-safety monitoring.

The company operates five product lines spanning distinct verticals: CALERA® for health, sports and work-safety wearables; CORE for direct-to-consumer sports sensors; gSKIN® for R&D-grade heat flux measurement; uval® for non-destructive U-value measurement in building energy assessment; and gRAY®/ray® for photonics and laser power sensing. AI-based algorithms layer on top of the sensor data for clinical and fertility analytics, and the technology has been validated in more than 10 clinical studies and won three CES Innovation Awards in 2022.

GreenTEG monetizes through a hybrid model combining hardware sales (CORE consumer devices at CHF 289.95–€329.95, uval kits, gSKIN research sensors), OEM licensing and white-label integration with global manufacturers, and distribution partnerships (notably an exclusive photonics relationship with Thorlabs for gRAY sensors). Customer concentration is spread across healthcare OEMs (Withings, Corsano Health), semiconductor partners (ams OSRAM), photonics (Thorlabs), sports teams (BORA-hansgrohe), research institutions (ETH Zurich, Duke, KIT), industrial buyers (Holcim, City of Basel), and a direct consumer base purchasing through corebodytemp.com and shop.greenteg.com.

Name

GreenTEG

Legal name

greenteg AG

Website

https://greenteg.com

Company type

Private

Founded year

2009

Operating status

Operating

Headcount range

11–50 employees

Short description

GreenTEG is a Swiss ETH Zurich spin-off that develops patented heat flux sensor technology (CALERA®) for non-invasive continuous core body temperature monitoring, licensing it to medical, wearable, and OEM partners while selling its own CORE sports and work-safety devices directly.

Ownership category

akta.pro rank

Product category

Thermal Sensors and Heat Flux Measurement

NAICS

Automatic Environmental Control Manufacturing for Residential, Commercial, and Appliance Use (334512), Electromedical and Electrotherapeutic Apparatus Manufacturing (334510)

SIC

Electromedical & Electrotherapeutic Apparatus (3845)

akta.pro primary industry

Environmental Sensors (Temperature/Humidity/Gas/Air Quality) (HDAHALAD)

akta.pro secondary industries

Continuous Temperature & Fever Monitoring (Wearable Thermometry) (HLAHACAK), Thermometers & Temperature Monitoring (Smart Thermometers) (CRACAQAG)

Keywords

• Heat flux sensors
• Thermal sensing solutions
• Core body temperature monitoring
• Wearable sensor technology
• Energy harvesting sensors

Headquarters

HQ city

Zürich

HQ country

Switzerland

HQ region

Europe

Offices1 record

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Personnel, Technology or R&D, Operations, Marketing or Sales, Infrastructure

Revenue model

1. Hardware Sensor Sales: Sale of proprietary heat flux sensors including CALERA, gSKIN, uval, and gRAY product lines for various applications.
2. OEM Integration Services: Technology licensing and integration services for embedding CALERA sensor technology into third-party wearables and medical devices, including white-label solutions.
3. Consumer Wearable Sales: Direct sales of CORE branded products to athletes and consumers via e-commerce channels.
4. Building Measurement Products: Sale of uval wireless and wired kits for U-value measurement in construction and building energy efficiency applications.

Pricing tiers

Go-to-market motion4 records

Distribution channels5 records

Marketing channels5 records

Core offering

GreenTEG develops and manufactures proprietary heat flux sensor technology centered on the CALERA® platform for non-invasive, continuous core body temperature monitoring. The company sells OEM sensor modules, the CORE/CORE 2 sports wearable, CORE Live workforce safety bundles, uval® U-value building measurement kits, gRAY® photonics laser sensors, and gSKIN® research heat flux sensors, while licensing CALERA® technology for integration into third-party wearables, medical devices, and smart textiles.

Product overview

GreenTEG is a Swiss thermal sensing technology company offering a portfolio of heat flux sensor products and solutions. The core technology CALERA® provides non-invasive core body temperature monitoring for wearables and medical devices. The product portfolio includes: CORE brand products (CORE, CORE 2) for sports performance monitoring; CORE Live and CORE Arx for work safety; CALERA® Health, Sports, and Work-Safety modules; uval® Building for U-value measurement; ray® Photonics for laser sensors; and gSKIN® for R&D applications. The company operates on a technology licensing model (OEM Integration) allowing partners like Corsano Health, Withings, and Thorlabs to incorporate their certified sensor technology into third-party products.

Differentiator

Problem solved

Functional benefit

Brands

• CALERA®: Brand name for medtech and wearable applications including core body temperature monitoring for health, sports, and work safety
• gSKIN®
• uval®
• ray®
• gRAY®
• CORE
• CORE Live
• CORE Arx

Products and services

• CALERA® Flagship heat flux sensor technology brand for non-invasive continuous core body temperature monitoring. Sold as an OEM module and licensed for integration into third-party wearables, medical devices, and smart textiles, and used directly in CALERA® Health, Sports, and Work-Safety solutions.
• CORE 2 Next-generation CORE sports wearable for real-time core body temperature monitoring during training and competition. 48% smaller and 30% lighter than its predecessor, with LED indicator, detachable attachment, BLE and ANT+ connectivity, designed for elite athletes, coaches, and sports scientists.
• CORE Live Workforce safety monitoring solution that uses CORE's proprietary heat flux technology to deliver continuous core body temperature, heat-strain, heart-rate, and skin-temperature data with configurable real-time alerts and geofencing for workers in extreme conditions.
• uval® Building Measurement Kit Wireless and wired U-value measurement kits for assessing thermal transmittance of building envelopes without drilling or damaging materials, used by building physicists, energy consultants, planners, and municipal inspectors for energy efficiency and insulation verification.
• gRAY® / ray® Photonics Sensors Wavelength-independent thermal power and beam-position sensors for laser output monitoring and industrial/medical laser systems. Supplied exclusively into Thorlabs' C-series thermal power sensors under an OEM partnership.
• gSKIN® R&D Heat Flux Sensors Patented high-sensitivity heat flux sensors for research and industrial applications including battery calorimetry, materials testing, aerospace, chemical process research, and bioscience, with deployments on the International Space Station.
• OEM Integration Services Technical integration services that license CALERA® heat flux sensor technology to device manufacturers for embedding into medical, wearable, and industrial products, including white-label and certified sensor solutions.

Quantifiable outcome

• 7 out of 10 top 2024 IRONMAN Kona finishers trust CORE technology
• +3 more outcomes

Named customers16 records

Segments6 records

Ideal customer profiles7 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Integration7 records

AI capability3 records

Feature6 records

Partnerships

13 partnerships are on record, tiered minor and core.

• SEF.GrowthminorGTM or Marketing Partner · 19 May 2026Recognition in SEF.Growth ecosystem, highlighting greenteg's innovation in body heat monitoring for early warning signals and sustainable growth.
• J-styleminorOEM/ Whitelabel/ Licensing Partner · 23 January 2026X7 Ring incorporating CALERA technology for health monitoring applications.
• Leitwert AGcoreStrategic or Co-development Partner · 23 April 2025Collaboration on remote patient monitoring systems, combining CALERA Research wearable with Leitwert's monitoring platform. Validated in field studies at University Hospital of Basel for at-home patient monitoring.
• Uppsala UniversityminorStrategic or Co-development Partner · 6 January 2025Dr. Jonathan Cedernaes from Uppsala University received top award in greenteg's 2nd call for research proposals, supporting sleep and circadian rhythm research using CALERA technology.
• ams OSRAMTechnology or Integration · 27 May 2024Greenteg became preferred partner for digital temperature sensor AS6221 integration. Sebastian Bauer, Head of Marketing at ams OSRAM, stated partnership sets new standards in health tracking technology.
• WithingscoreOEM/ Whitelabel/ Licensing Partner · 1 January 2023Integration of CALERA technology into Withings hybrid ScanWatch 2 and ScanWatch Nova Brilliant smartwatches, enabling continuous core body temperature monitoring in consumer health wearables.
• City of Baselminor8 December 2022City of Basel uses uval wireless kit for building energy efficiency assessments and municipal building inspections.
• Myant (Skiin)minorOEM/ Whitelabel/ Licensing Partner · 29 November 2022Skiin smart textiles with integrated CALERA sensor technology for continuous health monitoring through fabric.
• Corsano HealthcoreOEM/ Whitelabel/ Licensing Partner · 1 November 2022CALERA sensor technology integrated into CardioWatch 287, measuring core body temperature as one of eight vital parameters. Second-generation watch launched November 2022 with medical-grade multi-sensor wristband.
• University Hospital of BaselcoreStrategic or Co-development Partner · 1 January 2020Clinical research collaboration during COVID-19 for continuous core body temperature monitoring in quarantine facilities. Prof. Dr. Jens Eckstein led studies validating CALERA technology for remote patient monitoring.
• BORA-hansgroheminorOthers · 1 January 2020German cycling team used CORE sensors during Tour de France 2020 for real-time core body temperature monitoring.
• HolcimminorOthers · 1 January 2019Used uval wireless kit for hot box-cold box (HB/CB) testing in development of sustainable building materials. Holcim validated accuracy of U-value measurements for building envelope assessment.
• Thorlabs Inc.coreTechnology or Integration · 1 January 2017Exclusive partnership for gRAY sensor integration into Thorlabs photonics products. First gRAY sensors sold to Thorlabs in 2013, evolved into exclusive partnership covering C-series thermal power sensors for laser output monitoring. Thorlabs is a global market leader in devices and components for generating and measuring laser sources.

Scale indicators8 records

Recent moves3 records

Expansion highlights6 records

Direct peers

• Sensirion AG: Swiss MEMS environmental and gas sensor manufacturer. Highly comparable as a Switzerland-headquartered sensor specialist selling into medical, industrial, and HVAC applications; Dr. Pascal Gerner, Sensirion's Director of Sales & Marketing, sits on GreenTEG's board, signaling direct competitive overlap.
• Hukseflux Thermal Sensors: Dutch specialist in heat flux and thermal sensors used in building energy efficiency, R&D and industrial applications. Direct competitor in the thin-film heat flux sensor market alongside GreenTEG's gSKIN® and uval® product lines.
• Withings: French consumer health wearables maker that integrates CALERA® into ScanWatch 2 and Nova Brilliant for continuous core body temperature. Comparable as a customer and adjacent competitor to GreenTEG's own CORE-branded consumer products.
• Corsano Health: Swiss-Dutch medical-grade wearables company whose CardioWatch 287 embeds GreenTEG CALERA® for continuous vital sign monitoring. Closely comparable in remote patient monitoring positioning and form factor.
• EKO Instruments: Japan/US manufacturer of heat flux and net radiation sensors for building physics, solar and climate research. Direct peer in the same market research report alongside GreenTEG's gSKIN/uval product lines.

Broad incumbents

• ams OSRAM: Global semiconductor sensor incumbent and GreenTEG's preferred partner for AS6221 digital temperature sensor integration. Competes with GreenTEG's OEM sensor strategy at much greater scale across medical, automotive and consumer wearables.
• OMEGA Engineering (process sensing): Large industrial sensor manufacturer named alongside GreenTEG as a top-5 player in the thin-film heat flux sensor market; broader portfolio but directly overlapping in industrial thermal/heat-flux measurement.
• Hioki E.E. Corporation: Japanese test-and-measurement instrumentation maker identified as another top-5 thin-film heat flux sensor competitor. Comparable in industrial and R&D thermal measurement instrumentation.
• Maxim Integrated / Analog Devices (MAX30205 temperature sensor): Semiconductor incumbents offering clinical-grade digital temperature sensor ICs used in wearable and fever monitoring applications. Indirectly comparable as alternative temperature-sensing silicon that competes for the same OEM design wins as GreenTEG's heat-flux modules.

Emerging players

• Oura: Smart ring maker competing for the same continuous-temperature-and-recovery use case that J-style's CALERA-enabled X7 Ring targets. Comparable consumer wearable category with overlapping health-tracking value proposition.

Market position

Strengths4 records

Weaknesses4 records

Competitive moat6 records

Key risks5 records

Key highlights6 records

Customer concentration

• Xx.com/greenTEGAG
• LinkedInlinkedin.com/company/greenteg-ag
• Facebookfacebook.com/greenTEG

Compliance3 records

Revenue estimate

Valuation estimate

Number of profiles

Profiles9 records

Funding overview

Funding rounds4 records

Investors3 records

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about GreenTEG