Sonoff S31From real comments

Verdict distilled from 22 mentions across 10 aspects in comments under product review videos.

Positive sentiment59%
PROS 59%
CONS 41%

Rank based on 22 mentions across 10 aspects

View the verdict as

Buy this if...

  • You want power/energy monitoring on a budget smart plug
  • You plan to flash Tasmota or ESPHome for local Home Assistant control
  • You're comfortable troubleshooting WiFi pairing or MQTT connection issues

What users love

Skip this if...

  • Your network is 5GHz-only or you need guest-network isolation
  • You want a plug-and-play device with reliable first-time pairing
  • You're not comfortable soldering or using an FTDI programmer for flashing

What users complain about

Compare in seconds

Based on user comments

Best choiceYou are here
1Mid
Sonoff S31~$16
Easy Tasmota/ESPHome flashingBuilt-in power monitoringNo-solder flashing optionDifficult initial WiFi pairingFlashing/installation failuresGuest/5GHz network incompatibility
Sonoff S31~$16
Easy Tasmota/ESPHome flashing
Built-in power monitoring
No-solder flashing option
Difficult initial WiFi pairing
Flashing/installation failures
Guest/5GHz network incompatibility
2Value
Sonoff Mini R3~$11 · 1.5× cheaper
Solves no-neutral wiringWorks without WiFi or hubKeeps mechanical switch functionalBulky sizeNo ESP hardware or open firmwarePhysical fit uncertainty
Sonoff Mini R3~$11 · 1.5× cheaper
Solves no-neutral wiring
Works without WiFi or hub
Keeps mechanical switch functional
Bulky size
No ESP hardware or open firmware
Physical fit uncertainty
3Upper
Lenovo Smart Plug~$25 · 1.6× pricier
Fast HomeKit SetupWorks Immediately Out of the BoxApp Disconnect IssuesDual-Band Wifi Connection ProblemsReported Setup Hassles
Lenovo Smart Plug~$25 · 1.6× pricier
Fast HomeKit Setup
Works Immediately Out of the Box
App Disconnect Issues
Dual-Band Wifi Connection Problems
Reported Setup Hassles
4Mid
TP-Link Tapo P115~$20 · 1.2× pricier
Energy monitoring featurePhysical on/off switchPossible subscription fee for energy monitoringRequires continuous Wi-Fi connection
TP-Link Tapo P115~$20 · 1.2× pricier
Energy monitoring feature
Physical on/off switch
Possible subscription fee for energy monitoring
Requires continuous Wi-Fi connection
5Upper
TP-Link Kasa Smart Plug KP125~$25 · 1.6× pricier
Matter and ecosystem compatibilityPower monitoring interestAutomation capability uncertainNo live power reading displayUnclear API access for developers
TP-Link Kasa Smart Plug KP125~$25 · 1.6× pricier
Matter and ecosystem compatibility
Power monitoring interest
Automation capability uncertain
No live power reading display
Unclear API access for developers
6Mid
TP-Link Kasa Smart Plug HS103~$15 · similar price
Helpful Setup VideoSatisfaction Within TP-Link EcosystemDifficult Initial Setup for Some UsersReliability Failures Over Time
TP-Link Kasa Smart Plug HS103~$15 · similar price
Helpful Setup Video
Satisfaction Within TP-Link Ecosystem
Difficult Initial Setup for Some Users
Reliability Failures Over Time
7Upper
Philips Hue Dimmer Switch~$25 · 1.6× pricier
Long-term reliability for some usersWorks without a Hue bridgeGood battery lifeV2 removed useful V1 featuresConnection and pairing failuresLong-term support and subscription concerns
Philips Hue Dimmer Switch~$25 · 1.6× pricier
Long-term reliability for some users
Works without a Hue bridge
Good battery life
V2 removed useful V1 features
Connection and pairing failures
Long-term support and subscription concerns
8Mid
Sonoff Zigbee Dongle-E~$18 · similar price
Reliable pairing for many usersBroad device compatibilityCompelling price pointDifficult bootloader/flashing processInconsistent pairing especially with Aqara devicesWindows driver recognition problems
Sonoff Zigbee Dongle-E~$18 · similar price
Reliable pairing for many users
Broad device compatibility
Compelling price point
Difficult bootloader/flashing process
Inconsistent pairing especially with Aqara devices
Windows driver recognition problems
9Mid
TP-Link Kasa Smart Plug HS105~$20 · 1.2× pricier
Easy initial setup for many usersCompact stackable designPositive reviewer feedback on the explanation/video contentConnection drops and unreliable operation over timeDifficult or failed installation for some buyersWi-Fi setup and connection failures
TP-Link Kasa Smart Plug HS105~$20 · 1.2× pricier
Easy initial setup for many users
Compact stackable design
Positive reviewer feedback on the explanation/video content
Connection drops and unreliable operation over time
Difficult or failed installation for some buyers
Wi-Fi setup and connection failures
10Value
Sonoff Mini~$10 · 1.6× cheaper
Strong Tasmota and Home Assistant supportBroad smart home ecosystem compatibilityCompact size fits behind switchesConfusing relay/detach behavior for blinds and garage doorsNo-neutral wiring limitationsPossible standby noise and power draw concerns
Sonoff Mini~$10 · 1.6× cheaper
Strong Tasmota and Home Assistant support
Broad smart home ecosystem compatibility
Compact size fits behind switches
Confusing relay/detach behavior for blinds and garage doors
No-neutral wiring limitations
Possible standby noise and power draw concerns

Who wins on what (similar price)

Ranked by what users actually praise

Overall Impression

Power monitoring at a budget price is the standout feature. Multiple commenters highlight that the S31 provides watt, volt, and amp measurements that many pricier smart plugs don't include. One user called the value 'amazing' given the price, and another specifically bought it for the amp meter function, noting other smart plugs they'd seen lacked this capability entirely, making it a differentiator in its category.

Flashing with Tasmota or ESPHome is popular but inconsistent. Many reviewers praise how easy it is to flash the S31 with Tasmota for MQTT and Home Assistant integration, some using alligator clips to skip soldering. However, others report installation failures, devices losing control visibility until removed and re-added, and persistent MQTT reconnect errors, suggesting results vary by unit or firmware version and require troubleshooting patience.

Initial WiFi pairing frustrates a notable share of users. Several commenters describe lengthy, repeated pairing attempts, timeouts, and total failures connecting to guest networks or 5GHz WiFi, despite the device working fine on a primary 2.4GHz network. One user spent hours over several days getting devices to pair, and another couldn't connect five units at all, indicating setup reliability is a real weak point.

Outdated / Not-accurate data?