CircadiaOS
Legal

Terms of Service

Last Updated: April 22, 2026

1. Acceptance of Terms

By accessing, downloading, installing, or using the CircadiaOS application or any related services (collectively, the "Service"), you agree to be bound by these Terms of Service ("Terms"). If you do not agree to these Terms, you may not use the Service.

By tapping "I Agree," creating an account, or connecting the CircadiaOS application to your wearable device or smart thermostat, you acknowledge that you have read, understood, and agree to be bound by these Terms and our Privacy Policy.

CircadiaOS LLC ("CircadiaOS," "we," "us," or "our") reserves the right to modify these Terms at any time. We will notify you of material changes via the app or email. Continued use of the Service thirty (30) days after notice of such changes constitutes acceptance of the updated Terms.

2. Description of Service

CircadiaOS is a software application that integrates with your existing third-party wearable device and your existing third-party smart thermostat to generate a personalized overnight temperature schedule intended to support sleep quality.

CircadiaOS does not manufacture, sell, or distribute any hardware, wearable devices, thermostats, or HVAC equipment. The Service is software only. The Service is currently available on iOS.

2.1 How the Service Works

The Service operates on a next-morning, pre-sleep architecture. This is important for you to understand:

  • The Service does not monitor your biometric signals in real time during sleep, and it does not adjust your thermostat during the night based on moment-to-moment physiological changes. The third-party wearable devices supported by the Service deliver sleep data only after your sleep session is finalized. This is a constraint of the consumer wearable industry, not a limitation we have chosen.
  • Each morning, after your wearable device has delivered your prior-night sleep data, the Service computes a Sleep Quality Index (SQI) for that night using signals such as heart rate variability (HRV), sleep efficiency, total sleep time, and REM duration.
  • Before your next sleep session begins, the Service issues a four-phase temperature schedule to your smart thermostat. The schedule covers a pre-sleep period (beginning approximately 45 minutes before your target bedtime), an early-night period, a late-night period, and a pre-wake period.
  • The Service operates in two sequential phases. During an initial calibration phase, which requires approximately fourteen (14) qualifying nights of sleep data, the Service uses a fixed conservative temperature schedule while it establishes your personal baseline. During the subsequent personalization phase, the Service tests one schedule variable at a time against your established baseline and retains changes that appear favorable.
  • All temperature commands are constrained to stay within the temperature floor and ceiling you configure in the app. You set and control this range.

2.2 Compatible Wearable Devices

The Service currently supports the following wearable devices, accessed through the Terra API aggregation platform:

  • Apple Watch
  • Garmin
  • Fitbit
  • Oura Ring
  • Whoop

Not all features of the Service are available with all wearable devices. The specific biometric signals exposed by each wearable vary, and the Service adapts its computation accordingly. Wearables that expose richer signals (such as HRV samples or skin temperature delta) may enable more precise personalization. For a current list of supported wearable devices and per-device feature availability, visit circadiaos.com/compatibility. CircadiaOS reserves the right to update, add to, or reduce the list of compatible devices from time to time, and you agree that no such update shall entitle you to any refund or damages.

2.3 Compatible Smart Thermostats

The Service integrates with a range of smart thermostat systems through a third-party thermostat aggregation platform. For a current list of supported thermostats, visit circadiaos.com/compatibility. CircadiaOS reserves the right to update or reduce the list of compatible thermostats from time to time and you agree that no such update shall entitle you to any refund or damages.

2.4 Service Features

The Service includes the following features, which may vary based on your connected devices, your phase of use (calibration vs. personalization), and the signals exposed by your wearable:

  • Pre-sleep thermostat scheduling: Each night, before your target bedtime, the Service transmits a four-phase temperature schedule to your connected smart thermostat for the upcoming sleep session.
  • Calibration: For approximately your first fourteen (14) qualifying nights of use, the Service holds a fixed conservative temperature schedule while it establishes your personal sleep baseline. Personalization does not occur during calibration.
  • Personalization: After calibration, the Service sequentially tests one schedule variable at a time against your personal baseline, retains changes that appear favorable, and reverts changes that do not.
  • Sleep Quality Index (SQI) computation: Each morning, the Service computes a retrospective sleep quality score for the prior night using signals from your wearable device, including HRV, sleep efficiency, total sleep time, and REM duration where available.
  • Sleep data history: The app displays your recent SQI scores, your temperature schedule history, and summary sleep metrics sourced from your wearable device. The Service does not independently measure, generate, or verify any biometric data; all biometric data is sourced from your third-party wearable device and inherits that wearable's accuracy limitations.
  • User-configurable temperature range: You may configure a minimum and maximum temperature within the app. The Service will not transmit temperature commands outside this range under normal operation.
  • Optional user-reported context: The Service may prompt you to report optional context such as alcohol consumption, exercise, acute illness, and subjective stress. This information, when provided, is used to improve the accuracy of sleep attribution by flagging nights whose biometric patterns may be influenced by factors other than temperature.
  • Confound detection and block management: When the Service detects that a night's data is likely to have been influenced by non-temperature factors, the Service may exclude that night from personalization analysis, extend the current test period, or pause personalization until the influencing factor resolves.

The Service does not diagnose sleep disorders, does not rate the subjective quality of your sleep in absolute terms, and does not provide medical, therapeutic, or coaching recommendations. The SQI is a relative score normalized to your personal baseline and is used by the Service as an internal optimization target.

3. Medical Disclaimer

CircadiaOS is a wellness and lifestyle product. It is NOT a medical device, and has not been evaluated, cleared, or approved by the U.S. Food and Drug Administration (FDA) or any other regulatory body for the diagnosis, treatment, cure, mitigation, or prevention of any disease or medical condition.

  • The Service does not provide medical advice, medical diagnoses, or treatment recommendations.
  • The Service is not a substitute for professional medical advice, diagnosis, or treatment from a qualified healthcare provider.
  • You should not rely on the Service to make decisions about your health or medical care.
  • If you have or suspect you have a medical condition, including but not limited to sleep disorders such as sleep apnea, insomnia, narcolepsy, or restless leg syndrome, consult a licensed physician before using the Service.
  • Never disregard professional medical advice or delay seeking treatment because of information or data obtained through the Service.
  • The biometric data displayed by the Service is sourced from your third-party wearable device. CircadiaOS does not independently measure, verify, or guarantee the accuracy of any biometric data. That data is provided by your wearable device manufacturer and is subject to their terms, accuracy limitations, and disclaimers.
  • The Sleep Quality Index (SQI) computed by the Service is an internal optimization score, not a clinical measure of sleep health. It is normalized to your personal baseline and should not be interpreted as a diagnostic, prognostic, or comparative health metric.

CircadiaOS makes no representation or warranty that the Service will improve your sleep, health, or wellbeing. Individual results vary and are not guaranteed.

4. Safety Warnings and Assumption of Risk

PLEASE READ THESE SAFETY WARNINGS CAREFULLY BEFORE USING THE SERVICE.

4.1 Temperature Control Risks

The Service issues temperature adjustment commands to your third-party smart thermostat via its API. Although the Service constrains all commands within the temperature floor and ceiling you configure in the app, you acknowledge and accept the following risks:

  • Software malfunctions, bugs, connectivity interruptions, API errors, rate-limiting, or system failures may cause the thermostat to be set to unintended temperatures, including temperatures outside the configured operating range in rare or unforeseen circumstances.
  • Excessive API requests from the Service could potentially cause your thermostat to malfunction, become unresponsive, or behave unpredictably.
  • CircadiaOS does not manufacture, control, or warrant any third-party thermostat, HVAC system, or wearable device. We are not responsible for the behavior, malfunction, or failure of any third-party hardware or software.
  • Prolonged exposure to extreme temperatures during sleep can pose serious health risks, including hypothermia, hyperthermia, heat stroke, dehydration, cardiovascular strain, or death, particularly for vulnerable individuals.
  • You are solely responsible for ensuring that your thermostat and HVAC system have appropriate safety limits, fail-safes, and manual overrides configured independent of CircadiaOS. The user-configurable temperature range within CircadiaOS is a software-level safeguard and should not be relied upon as your sole safety mechanism.
  • CircadiaOS is not responsible for any damage to your thermostat, HVAC system, or any other equipment resulting from the use of the Service, including but not limited to damage caused by excessive API calls, software errors, or incompatible firmware updates.

4.2 Vulnerable Populations

CircadiaOS is designed for use by healthy adults. The Service is NOT recommended for use in environments where the following individuals sleep without direct supervision by a capable adult:

  • Infants, toddlers, or children under the age of 12; provided for the avoidance of doubt users must be 18 years of age to create their own account
  • Elderly individuals, particularly those with cognitive impairments or limited mobility
  • Individuals with medical conditions that affect thermoregulation, cardiovascular function, or respiratory function, including but not limited to hypertension, congestive heart failure, peripheral vascular disease, or autonomic dysfunction
  • Individuals who are incapacitated, sedated, or under the influence of substances that impair their ability to wake and respond to environmental conditions

If you choose to use the Service in an environment with vulnerable individuals, you do so entirely at your own risk and assume full responsibility for any consequences.

4.3 Network and Connectivity

The Service requires an active internet connection to receive sleep data from your wearable device provider and to issue temperature schedules to your thermostat. You acknowledge that:

  • Loss of internet connectivity, power outages, Wi-Fi interruptions, Bluetooth disconnections, or server downtime may prevent the Service from receiving your biometric data or issuing a schedule to your thermostat.
  • In the event of a connectivity failure, your thermostat will remain at its last programmed setting or revert to its own default behavior. CircadiaOS has no control over thermostat behavior when communication is interrupted.
  • CircadiaOS does not guarantee uninterrupted or error-free operation of the Service.
  • Delays in data delivery from your wearable device provider may cause the Service to compute an SQI or issue a schedule based on outdated or incomplete data, or to skip personalization for that cycle entirely.

4.4 Third-Party Wearable Device Data

The Service relies on biometric data provided by your third-party wearable device, delivered to the Service through a third-party aggregation platform. You acknowledge that:

  • CircadiaOS does not control, generate, or verify the accuracy of biometric data from your wearable device.
  • Inaccurate, delayed, incomplete, or missing biometric data from your wearable device may cause the Service to compute an incorrect SQI, make inappropriate personalization decisions, or issue a suboptimal temperature schedule.
  • Your wearable device manufacturer and the third-party aggregation platform may update, modify, or discontinue their product, firmware, or API at any time, which may affect the functionality of the Service without notice.
  • Different wearable devices expose different signals with different levels of accuracy. The quality and precision of the Service varies by wearable.
  • CircadiaOS is not responsible for any consequences arising from inaccurate or unavailable wearable device data.

4.5 Assumption of Risk

BY USING THE SERVICE, YOU EXPRESSLY ACKNOWLEDGE AND AGREE THAT YOUR USE OF THE SERVICE IS AT YOUR SOLE RISK. YOU VOLUNTARILY ASSUME ALL RISKS ASSOCIATED WITH THE USE OF THE SERVICE, INCLUDING BUT NOT LIMITED TO RISKS ARISING FROM SOFTWARE MALFUNCTIONS, TEMPERATURE CONTROL ERRORS, API FAILURES, DATA INACCURACIES, THIRD-PARTY DEVICE INCOMPATIBILITIES, AND DAMAGE TO THIRD-PARTY EQUIPMENT.

5. Third-Party Devices and Services

The Service integrates with third-party wearable devices and smart thermostat systems through their respective APIs and through third-party aggregation platforms (currently including, but not necessarily limited to, Terra for wearable devices). CircadiaOS is a software intermediary and does not manufacture any hardware. You acknowledge and agree that:

  • CircadiaOS does not manufacture, sell, endorse, or warrant any third-party wearable device, thermostat, HVAC system, aggregation platform, or other hardware.
  • Third-party manufacturers, aggregation platforms, or API providers may update, modify, or discontinue their products, firmware, or APIs at any time, which may affect or entirely disable the functionality of the Service. CircadiaOS is not responsible for changes made by third-party manufacturers, aggregation platforms, or API providers.
  • Compatibility with third-party devices is provided on an "as available" basis and is not guaranteed for any specific device, firmware version, or operating system version.
  • Your use of third-party devices, aggregation platforms, and services is governed by the respective provider's terms and conditions and privacy policies, not these Terms. You are responsible for reviewing and complying with those terms.
  • CircadiaOS is not responsible for any damage to, malfunction of, or warranty voiding of your third-party wearable device, thermostat, HVAC system, or any other connected equipment arising from your use of the Service.

6. User Responsibilities

As a user of the Service, you agree to:

  • Use the Service only for its intended purpose as a lifestyle product.
  • Configure an appropriate temperature floor and ceiling within the CircadiaOS app before activating the Service, and review these settings periodically.
  • Maintain appropriate safety settings and temperature limits on your thermostat and HVAC system independent of CircadiaOS. Do not disable built-in safety features or override manufacturer temperature limits.
  • Regularly verify that your thermostat is functioning correctly and not rely solely on CircadiaOS for temperature management.
  • Keep your wearable device, thermostat, app, and connected systems updated to the latest software and firmware versions.
  • Provide accurate information during onboarding, including age, sex, sleep schedule, ZIP code, and any relevant health flags (such as insomnia history, chronic anxiety, hypertension, or menopause status) that inform the Service's decisions.
  • Not use the Service as a substitute for medical devices, medical advice, or professional healthcare.
  • Supervise the use of the Service in any environment where vulnerable individuals (as described in Section 4.2) are present.
  • Not reverse engineer, decompile, disassemble, or otherwise attempt to derive the source code, models, algorithms, or data schemas of the Service.
  • Comply with all applicable laws and regulations in your jurisdiction.

7. Subscription, Fees, and Refunds

The Service is offered in two tiers: a free plan with no time limit, and a paid Premium subscription. Current Premium pricing is $12.99 per month (billed monthly) or $99.99 per year (billed annually), through the Apple App Store. Pricing is subject to change; changes to the subscription fee will be communicated at least thirty (30) days in advance and will only apply to subsequent billing cycles. Your subscription will automatically renew unless canceled. You may cancel at any time through your Apple subscriptions in iPhone Settings. If you cancel, your subscription will remain active through the end of your current paid billing cycle, after which no further charges will occur.

Payment is processed by third-party payment processors. CircadiaOS does not store full payment card information. Refund requests will be evaluated on a case-by-case basis; except where required by law, fees are non-refundable for partial months of service.

8. Limitation of Liability

TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW:

CIRCADIAOS, ITS OFFICERS, DIRECTORS, MEMBERS, EMPLOYEES, AGENTS, PARTNERS, AND LICENSORS SHALL NOT BE LIABLE FOR ANY INDIRECT, INCIDENTAL, SPECIAL, CONSEQUENTIAL, OR PUNITIVE DAMAGES, INCLUDING BUT NOT LIMITED TO DAMAGES FOR LOSS OF PROFITS, GOODWILL, USE, DATA, OR OTHER INTANGIBLE LOSSES, RESULTING FROM:

  • Your use of or inability to use the Service
  • Any conduct or content of any third party on or related to the Service
  • Any temperature changes, HVAC behavior, or environmental conditions resulting from use of the Service
  • Any damage to, malfunction of, or warranty voiding of your thermostat, HVAC system, wearable device, or other equipment
  • Unauthorized access, use, or alteration of your data or transmissions
  • Any malfunction, error, or failure of the application or third-party systems (including aggregation platforms)
  • Any personal injury, property damage, or health effects arising from or related to use of the Service
  • Inaccurate, delayed, or unavailable biometric data from your wearable device
  • Any schedule issued by the Service that produces an unexpected or undesired sleep environment

IN NO EVENT SHALL CIRCADIAOS'S TOTAL AGGREGATE LIABILITY TO YOU FOR ALL CLAIMS ARISING FROM OR RELATED TO THE SERVICE EXCEED THE GREATER OF (A) THE AMOUNT YOU PAID TO CIRCADIAOS IN THE TWELVE (12) MONTHS PRECEDING THE CLAIM, OR (B) ONE HUNDRED DOLLARS ($100.00).

SOME JURISDICTIONS DO NOT ALLOW THE EXCLUSION OR LIMITATION OF CERTAIN DAMAGES. IF THESE LAWS APPLY TO YOU, SOME OR ALL OF THE ABOVE EXCLUSIONS OR LIMITATIONS MAY NOT APPLY, AND YOU MAY HAVE ADDITIONAL RIGHTS.

9. Warranty Disclaimer

THE SERVICE IS PROVIDED ON AN "AS IS" AND "AS AVAILABLE" BASIS, WITHOUT WARRANTIES OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE, AND NON-INFRINGEMENT.

WITHOUT LIMITING THE FOREGOING, CIRCADIAOS DOES NOT WARRANT THAT:

  • The Service will meet your requirements or expectations
  • The Service will be uninterrupted, timely, secure, accurate, or error-free
  • The data, SQI scores, schedules, or other outputs obtained through the Service will be accurate, reliable, or complete
  • Any defects in the Service will be corrected
  • The Service will be compatible with your wearable device, thermostat, or other devices now or in the future
  • The Service will improve your sleep quality, health, or wellbeing
  • The Service will not cause damage to, or interfere with the operation of, your third-party devices

10. Indemnification

You agree to defend, indemnify, and hold harmless CircadiaOS, its officers, directors, members, employees, agents, and affiliates from and against any and all claims, damages, losses, liabilities, costs, and expenses (including reasonable attorneys' fees) arising from or related to:

  • Your use or misuse of the Service
  • Your violation of these Terms
  • Your violation of any applicable law or regulation
  • Any claim by a third party arising from your use of the Service, including claims related to property damage, personal injury, health effects, or damage to third-party equipment
  • Your failure to configure or maintain appropriate temperature safety settings on your thermostat, HVAC system, or within the CircadiaOS application
  • Any inaccurate information you provide during onboarding or through in-app prompts, including age, health status, or sleep schedule

11. Dispute Resolution and Arbitration

PLEASE READ THIS SECTION CAREFULLY. IT AFFECTS YOUR LEGAL RIGHTS, INCLUDING YOUR RIGHT TO FILE A LAWSUIT IN COURT AND TO HAVE A JURY TRIAL.

11.1 Mandatory Arbitration

You and CircadiaOS agree that any dispute, claim, or controversy arising out of or relating to these Terms or the Service (collectively, "Disputes") will be resolved through binding individual arbitration, rather than in court, except that either party may seek equitable relief in court for infringement or misuse of intellectual property rights. Each party will bear its own fees in such arbitration, except that CircadiaOS will pay all filing, administration, and arbitrator fees beyond the initial filing fee.

11.2 Class Action Waiver

YOU AND CIRCADIAOS AGREE THAT EACH PARTY MAY BRING CLAIMS AGAINST THE OTHER ONLY IN AN INDIVIDUAL CAPACITY, AND NOT AS A PLAINTIFF OR CLASS MEMBER IN ANY PURPORTED CLASS, CONSOLIDATED, OR REPRESENTATIVE PROCEEDING. THE ARBITRATOR MAY NOT CONSOLIDATE MORE THAN ONE PERSON'S CLAIMS AND MAY NOT PRESIDE OVER ANY FORM OF REPRESENTATIVE OR CLASS PROCEEDING.

11.3 Arbitration Rules

Arbitration shall be administered by the American Arbitration Association ("AAA") under its Consumer Arbitration Rules. The arbitration shall take place in Wilmington, Delaware or, at the election of the claimant, via telephone or video conference. The arbitrator's decision shall be final and binding.

11.4 Governing Law

These Terms shall be governed by and construed in accordance with the laws of the State of Delaware, without regard to its conflict of laws principles.

12. Intellectual Property

Subject to the terms of our Privacy Policy governing the use of personal data, the Service, including all content, features, functionality, software, algorithms, machine learning models, the Sleep Quality Index (SQI) formulation, baseline schedules, personalization logic, data analyses, designs, text, graphics, and trademarks, is owned by CircadiaOS LLC and is protected by United States and international intellectual property laws. You are granted a limited, non-exclusive, non-transferable, revocable license to use the Service for personal, non-commercial purposes in accordance with these Terms. You agree that such license and your use of the Service does not entitle you to any ownership rights to intellectual property owned or licensed by CircadiaOS LLC.

You may not copy, modify, distribute, sell, lease, sublicense, reverse engineer, decompile, or create derivative works based on the Service without prior written consent from CircadiaOS.

All aggregated data, anonymized datasets, machine learning models, SQI analyses, sleep science findings, and algorithmic insights derived from user data are the exclusive intellectual property of CircadiaOS LLC.

13. Account and Eligibility

You must be at least 18 years of age to create an account and use the Service. By creating an account, you represent and warrant that you are at least 18 years old and that the information you provide, including age, sex, sleep schedule, and any optional health flags, is accurate and complete.

You are responsible for maintaining the confidentiality of your account credentials and for all activities that occur under your account.

14. Force Majeure

You agree that CircadiaOS will not be liable for inadequate performance to the extent caused by a condition (for example, natural disaster, act of war or terrorism, riot, labor condition, governmental action, and internet disturbance) that was beyond CircadiaOS's reasonable control. CircadiaOS will use commercially reasonable efforts to provide notice of any force majeure event and its performance obligations will be suspended during the occurrence of such event.

15. Termination

CircadiaOS may suspend or terminate your access to the Service at any time, with or without cause, with or without notice. Upon termination, your right to use the Service ceases immediately and you will be eligible for a pro rata refund of any remaining subscription term. Sections 3, 4, 8, 9, 10, 11, 12, and 14 shall survive termination.

16. Severability

If any provision of these Terms is found to be unenforceable or invalid, that provision shall be limited or eliminated to the minimum extent necessary so that the remaining provisions of these Terms remain in full force and effect.

17. Entire Agreement

These Terms, together with the Privacy Policy, constitute the entire agreement between you and CircadiaOS regarding the Service and supersede all prior agreements and understandings.

18. Apple App Store Additional Terms

If you downloaded the CircadiaOS application from the Apple App Store, the following additional terms apply:

  • These Terms are an agreement between you and CircadiaOS LLC only, not with Apple Inc. ("Apple").
  • Apple has no obligation to provide any maintenance or support services for the Service.
  • In the event of any failure of the Service to conform to any applicable warranty, you may notify Apple, and Apple will refund the purchase price of the Service (if any) to you. To the maximum extent permitted by applicable law, Apple will have no other warranty obligation whatsoever with respect to the Service.
  • Apple is not responsible for addressing any claims by you or any third party relating to the Service or your possession and use of it, including product liability claims, claims that the Service fails to conform to any applicable legal or regulatory requirement, and claims arising under consumer protection or similar legislation.
  • In the event of any third-party claim that the Service or your possession and use of the Service infringes that third party's intellectual property rights, CircadiaOS, not Apple, will be solely responsible for the investigation, defense, settlement, and discharge of any such claim.
  • You represent and warrant that you are not located in a country subject to a U.S. government embargo, and that you are not listed on any U.S. government list of prohibited or restricted parties.
  • Apple and Apple's subsidiaries are third-party beneficiaries of these Terms, and upon your acceptance of these Terms, Apple will have the right (and will be deemed to have accepted the right) to enforce these Terms against you as a third-party beneficiary thereof.

19. Contact Information

If you have questions about these Terms, please contact us at:

CircadiaOS LLC

Email: support@circadiaos.com

Website: circadiaos.com