Privacy
Private by design.
Sleep is the most intimate thing you do. At Onethird, we protect that intimacy. We believe we can train our AI and improve sleep technologies without ever knowing who you are. Our systems separate your identity from your sleep data, making it technically impossible to link your data back to you. We study the sleep, not the sleeper.
Features
We’re committed to protecting your personal data.
On-Device Processing
Your Celsius is powered by SERA, our Sleep Environment Regulating AI. Unlike many smart devices, SERA runs locally on your Celsius hardware. By processing your data on-device, your most sensitive information never has to leave your home. This also ensures total stability: whether there is a local internet outage or a server-side disruption, SERA continues to optimise your sleep without interruption.
Full De-identification
To improve our algorithms for the entire Onethird community, Celsius periodically sends technical sleep data to our servers (every 10 days). Before this data is sent, every personal identifier is stripped away. We collect data on thermal trends and bed activity to train our AI, but this data is never linked to your account and will never reveal your identity. We are interested in how humans sleep, not who they are.
The Right to Anonymity
You should not have to trade your identity for a better night’s sleep. Onethird does not require your real name to sign up or use our services. You are encouraged to use a unique username or alias. While we require an email or mobile number for account recovery and to ensure our users are human, these are kept separate from your sleep metrics.
Always Ask, Always Inform
We believe in full transparency. Onethird will never collect data without your explicit permission. We will always inform you exactly what data is being requested and how it will be used to improve your experience. You remain the final authority on what you share.
Onethird Privacy Policy
Updated January 8, 2026
This Privacy Policy describes how Onethird ("we," "us," or "our") handles information across our products (including SOMA), applications, and services.
Information Collection and Hardware Limits
Our hardware is designed with privacy as a physical constraint.
Thermal Sensors Only: Celsius sensors only collect multi-point temperature data within the bed. There are no microphones, cameras, or optical sensors.
Derived Insights: From temperature data alone, our SERA model derives:
User presence, posture, and motion.
Bedding arrangements and thermal irregularities.
Biological markers such as skin temperature trends and distal-to-proximal gradients.
Optional Personal Metrics: For maximum efficacy, users may choose to provide their age, sex, body weight, and sleep conditions. This data is immediately anonymised and is used solely to tune the AI to your specific physiology.
Registration and Identity
Anonymity: We do not force customers to provide personal identification. You reserve the right to stay anonymous through usernames and aliases.
Verification: An email address and mobile number are required only for the ease of login and password recovery.
Marketing: Promotional communications are strictly opt-in. We do not send ads unless you explicitly ask for them.
Data Usage and Sharing
Optimisation: We use your data to improve our algorithms and make our sleep optimisation services more effective.
No Data Sales: Under no circumstances does Onethird sell, rent, or trade data linked to user identity to third parties.
Legal Compliance: Because your sleep data is de-identified and decoupled from your identity, we cannot provide "your" sleep data to outside parties because we cannot verify it belongs to you.
Security and Storage
We use industry-standard encryption for any data transmitted to our servers. Because your SERA model runs locally, your raw, minute-by-minute sleep data stays on your device, not our servers.
Your Rights and Controls
You have the right to:
Use our products without revealing your identity.
Withdraw consent for data collection at any time.
Access or delete your account and associated verification data.