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Temtop C1+ Review: Bluetooth CO₂ Monitoring and Data History

The Temtop C1+ takes the compact C1 formula and adds a bigger screen, a named Sensirion CO₂ sensor and a Bluetooth app. This review looks at what the app adds, how the ECO mode battery figure is achieved and where the C1+ sits against the Aranet4.

By the Akermin Editorial Team · 4 min read

As an Amazon Associate, Akermin earns from qualifying purchases. Product links on this page are affiliate links.

Temtop C1+ Review: Bluetooth CO₂ Monitoring and Data History

Temtop · Temtop C1+ CO2 Monitor, Smart Indoor Air Quality Monitor with BLE App

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Price and availability are shown on Amazon and can change at any time.

Verdict

The C1+ is the connected version of Temtop’s compact CO₂ monitor. It keeps the CO₂, temperature and humidity readings, moves them to a 3.3-inch LCD that shows everything at once, names a Sensirion sensor in the listing, and adds a Bluetooth app with history and firmware updates. Battery life is quoted at up to 70 days in ECO mode from an 800 mAh cell. It is a well-judged middle option: more useful than the display-only C1, far lower in price than an Aranet4, and free of any cloud dependency. The trade-offs are Bluetooth-only syncing and an LCD that is not as readable from across the room as e-ink.

Who It Is For

  • People who want to see the overnight CO₂ curve in a bedroom without buying a premium monitor.
  • Home offices where the number on the desk and a graph on the phone are both useful.
  • Anyone who wants a real CO₂ sensor from a named supplier at a moderate price.

Our guide to using a CO₂ monitor in a home office covers the placement and thresholds that suit it.

Documented Specifications

Item Documentation
CO₂ sensor Sensirion, described as high precision
Other measurements Temperature, relative humidity
Display 3.3-inch LCD, multiple parameters at once
Battery 800 mAh lithium, up to 70 days in ECO mode
Alerts Colour coding, prominent CO₂ number, optional buzzer
Connectivity Bluetooth Low Energy to the Temtop app
Updates OTA firmware updates via the app

The Sensirion Sensor

Sensirion is a Swiss sensor manufacturer whose compact CO₂ modules are used across the consumer monitor market, including in some monitors that cost several times as much as the C1+. Its compact sensors use a photoacoustic infrared principle, so they measure actual CO₂ rather than estimating it. The two things worth knowing are that the sensor benefits from seeing fresh air periodically for its automatic baseline correction, and that the manufacturer’s accuracy class is suitable for ventilation decisions rather than laboratory work. Details on the sensor families are in NDIR versus photoacoustic CO₂ sensors, and calibration steps in how to calibrate a CO₂ monitor.

Display and Battery

The LCD shows CO₂, temperature and humidity together with a colour band. It is clear at desk distance and readable in normal room light, but unlike an e-ink screen it needs a backlight to read in the dark and the backlight costs battery. The 70-day figure is for ECO mode, which lengthens the sampling interval. If you want the reading to track a room quickly, use the standard mode and expect to charge more often. The buzzer is optional and can be left off in a bedroom.

Placement follows the usual rules for a compact CO₂ monitor: at breathing height, away from windows, doors and your own exhaled breath, and not on top of a warm device. Because the sensor responds to pressure changes, a spot away from a fan or an air conditioning outlet gives steadier readings. Our guide on placing a CO₂ monitor covers the details.

App and History

The Temtop app connects over Bluetooth Low Energy, shows live readings and stores history for graphs. Because there is no cloud, the phone must be near the monitor to pull the data, which suits a home but not a remote property. The app also carries firmware updates, which is unusual at this price and means sensor algorithms can improve over time. Bluetooth versus Wi-Fi is discussed in this guide.

Strengths

  • Named Sensirion sensor at a moderate price.
  • All readings on one large screen.
  • Long battery life in ECO mode and USB charging.
  • App history and OTA updates with no account.

Limitations

  • Bluetooth only; no remote alerts.
  • LCD needs backlight in the dark, unlike e-ink.
  • No particle or VOC sensing.

How It Compares

The Temtop C1 is the same idea without the app and with a smaller screen. The Aranet4 HOME offers an e-ink display and years of battery life for far more. The SwitchBot Meter Pro CO₂ adds a clock and smart-home integration through a hub. The C1+ is the value pick for a connected CO₂ monitor.

How We Research

This review is based on Temtop’s published specifications, the Amazon listing and owner reports. We did not run laboratory tests.

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Qingping CO2 Monitor Thermometer Hygrometer, Remote Monitoring via Qingping IoT, Temperature and Humidity Monitor for Different Scenarios, Fast Alert Notification, Rechargeable Battrey

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Products shown because their documented specifications fit this guide. Price and availability are on Amazon and can change.

Frequently Asked Questions

What sensor does the C1+ use?

The listing names a Sensirion CO₂ sensor. Sensirion's compact CO₂ sensors use a photoacoustic infrared principle and are widely used in consumer monitors.

Does the app work without Wi-Fi?

Yes. The C1+ uses Bluetooth Low Energy. The phone needs to be within range to sync; there is no cloud account.

How long does the battery really last?

The listing states up to 70 days in ECO mode from the 800 mAh battery. Continuous mode with the backlight on will be shorter. Owners generally report weeks rather than days.

Can the firmware be updated?

Yes. The listing states that the C1+ supports over-the-air updates through the app.

Affiliate disclosure: Akermin earns a commission from qualifying Amazon purchases made through links on this page. Our editorial picks are based on documented specifications and owner feedback, not commissions.