# Temtop S1 Air Quality Monitor, PM2.5 AQI, Colour LCD

Source: https://www.ranked10.co.uk/home/best-air-quality-monitor/temtop-s1-pm25
Ranked #9 in "Best Air Quality Monitor 2026: Fewer Numbers, Better Sensors": https://www.ranked10.co.uk/home/best-air-quality-monitor

- Price: £29.99 (checked on Amazon UK on 2026-09-11)
- Amazon rating: 4.2 from 130 ratings
- Buy on Amazon: https://www.amazon.co.uk/dp/B0DK2RQKCK?tag=ranked10-21

The Temtop S1 is the cheapest monitor in this ranking at £29.99, and it measures PM2.5 particles, an AQI number, temperature and humidity on a colour LCD. Battery life is rated at up to 60 days in ECO mode or around 20 days in smart mode, and it weighs 160g.

It is ninth on purpose: no CO2, no VOCs, and an AQI figure derived from the particle reading rather than measured. What is interesting is its rating shape — 39 per cent of its 130 ratings are four stars rather than five, which says the device works with one annoyance rather than failing.

## Specification

| Field | Value |
|---|---|
| What it measures | PM2.5, AQI, temperature, humidity |
| Display | Colour LCD |
| Battery | Up to 60 days in ECO mode |
| Ratings | 4.2 from 130 |
| Item weight | 160 g |
| Price | £29.99 |

## Questions people ask

**Does it measure CO2?**

No. It measures PM2.5 particles, an AQI number, temperature and humidity. For CO2 you need the Aranet4, the SONOFF or the Temtop C1.

**What do ECO and Smart modes do?**

ECO mode samples less often, with battery life rated at up to 60 days; smart mode samples more often for around 20 days.

**Why are so many reviews four-star?**

39 per cent of its 130 ratings are four stars rather than five, which usually means the product works with one annoyance. Here the reviews mention battery life and sampling.

**Is the AQI number a measurement?**

It is derived from the particle reading onto a 0-500 scale. The PM2.5 figure behind it is the measurement.

**Who is it for?**

Anyone who wants a cheap particle reading, or wants to check whether an air purifier is making a difference in one room.

**How many ratings does it have?**

130 at the time of collection, averaging 4.2 stars, with 49 per cent five-star and 5 per cent one-star.