# Extech 45158 Mini Thermo-Anemometer with Humidity vs testo 405i Smart Probe Thermal Anemometer: specs and price compared

A sourced, side-by-side comparison of the Extech 45158 Mini Thermo-Anemometer with Humidity (Extech Instruments) and testo 405i Smart Probe Thermal Anemometer (Testo) among anemometers.

## Side by side

| Spec | Extech 45158 Mini Thermo-Anemometer with Humidity | testo 405i Smart Probe Thermal Anemometer |
| --- | --- | --- |
| US price | not published | $123.95 |
| Brand | Extech Instruments | Testo |
| Wind speed range ms | 1.1 to 20 m/s (2.5-44.7 mph) | 0 to 30 m/s |
| Airflow cfm cmm | — | — |
| Velocity accuracy | ±(3% of reading + 0.4 mph) | ±(0.1 m/s + 5% of reading) below 2 m/s; ±(0.3 m/s + 5% of reading) 2-15 m/s |
| Sensor type | Vane, 1 in. (24mm) diameter | Hot-wire (thermal), foldable telescopic probe |
| Temperature range | -18 to 50 °C (0 to 122 °F), ±1 °C accuracy | 0 to 50 °C (32 to 122 °F) |
| Data hold logging | Data hold; selectable 5/10/13-second averaging (no onboard SD/USB logging) | Hold/min/max/logging via Bluetooth-paired testo Smart App; no onboard display |
| Backlit display | Yes | No |

## Key differences

- Wind speed range ms: Extech 45158 Mini Thermo-Anemometer with Humidity 1.1 to 20 m/s (2.5-44.7 mph) vs testo 405i Smart Probe Thermal Anemometer 0 to 30 m/s
- Velocity accuracy: Extech 45158 Mini Thermo-Anemometer with Humidity ±(3% of reading + 0.4 mph) vs testo 405i Smart Probe Thermal Anemometer ±(0.1 m/s + 5% of reading) below 2 m/s; ±(0.3 m/s + 5% of reading) 2-15 m/s
- Sensor type: Extech 45158 Mini Thermo-Anemometer with Humidity Vane, 1 in. (24mm) diameter vs testo 405i Smart Probe Thermal Anemometer Hot-wire (thermal), foldable telescopic probe
- Temperature range: Extech 45158 Mini Thermo-Anemometer with Humidity -18 to 50 °C (0 to 122 °F), ±1 °C accuracy vs testo 405i Smart Probe Thermal Anemometer 0 to 50 °C (32 to 122 °F)
- Data hold logging: Extech 45158 Mini Thermo-Anemometer with Humidity Data hold; selectable 5/10/13-second averaging (no onboard SD/USB logging) vs testo 405i Smart Probe Thermal Anemometer Hold/min/max/logging via Bluetooth-paired testo Smart App; no onboard display
- Backlit display: Extech 45158 Mini Thermo-Anemometer with Humidity Yes vs testo 405i Smart Probe Thermal Anemometer No

## Sources

- Extech 45158 Mini Thermo-Anemometer with Humidity: https://www.extech.com/products/45158 (extech.com, verified 2026-08-09)
- testo 405i Smart Probe Thermal Anemometer: https://www.testo.com/en-US/testo-405i/p/0560-1405 (testo.com, verified 2026-08-09)

Canonical: https://frontdeskreview.com/gear/anemometers/extech-45158-vs-testo-405i/
Cite: Per The Front Desk Review, Extech 45158 Mini Thermo-Anemometer with Humidity (not published) vs testo 405i Smart Probe Thermal Anemometer ($123.95) — sourced spec-by-spec comparison at https://frontdeskreview.com/gear/anemometers/extech-45158-vs-testo-405i/
License: CC BY 4.0.