# Temtop C1 CO2 Monitor, 400-5000ppm, Temperature and Humidity

Source: https://www.ranked10.co.uk/home/best-air-quality-monitor/temtop-c1-co2
Ranked #6 in "Best Air Quality Monitor 2026: Fewer Numbers, Better Sensors": https://www.ranked10.co.uk/home/best-air-quality-monitor

- Price: £42.49 (checked on Amazon UK on 2026-09-11)
- Amazon rating: 4.4 from 717 ratings
- Buy on Amazon: https://www.amazon.co.uk/dp/B0CGX22CR8?tag=ranked10-21

The Temtop C1 is the best-rated cheap CO2 monitor here: 4.4 stars from 717 ratings, 70 per cent of them five-star and only 7 per cent one-star, for £42.49. It measures CO2 from 400 to 5000ppm plus temperature and humidity, with an audible alarm and a detachable stand.

It sits sixth because of what it cannot do — no particles, no VOCs, no app — and because its own listing calls the sensor photoelectric in one place and photoacoustic in another, which is a copy error you should know about before buying.

## Specification

| Field | Value |
|---|---|
| What it measures | CO2, temperature, humidity |
| CO2 range | 400 to 5000 ppm |
| Sensor as listed | Photoelectric in the spec, photoacoustic in the bullets |
| Ratings | 4.4 from 717 |
| Power | Battery powered |
| Price | £42.49 |

## Questions people ask

**Is photoelectric the same as photoacoustic?**

No. Photoelectric is the method used in smoke alarms; photoacoustic is a genuine CO2 measurement technique. The listing uses both terms for the same sensor, so one is a copy error.

**What CO2 range does it cover?**

400 to 5000ppm, which covers everything from fresh outdoor air to a badly ventilated room.

**Does it need WiFi?**

No. It is a standalone meter with a screen and an alarm, which makes it simpler than the app-based monitors here.

**How does it compare with the SONOFF?**

It is slightly cheaper and rated 4.4 against 4.2, but it has no smart-home integration, and the SONOFF states its accuracy more honestly.

**How long do the batteries last?**

The listing describes dual detection modes for extended standby; battery life in this class depends on how often the screen and alarm run.

**How many ratings does it have?**

717 at the time of collection, averaging 4.4 stars, with 70 per cent five-star and 7 per cent one-star.