Short answer: Order a Somfy Sonesse 40 when the shade tube measures at least 1.46 in (37 mm) inside and the fabric needs 3 to 9 Nm. Then pick the version by control: RTS for remotes, WT for a wired wall switch, Zigbee 3.0 for TaHoma and voice control, RS485 for SDN projects, or WireFree for windows with no outlet nearby.
The Sonesse 40 sits in the middle of Somfy's interior shade range. It drops into tubes too small for an LT50 and lifts fabric too heavy for a Sonesse 30. Somfy builds the same 40 mm body in six control versions, and the part number you order depends on two decisions: the torque your shade needs and the way the building will run it.
Does a Sonesse 40 fit your tube?
Start with the tube, because no control choice rescues a motor that will not slide in. Somfy publishes a minimum internal tube diameter of 1.46 in (37 mm) for the Sonesse 40, and the motor body measures 1.57 in across its widest point. Measure inside the tube wall with calipers. A tube that measures 1.5 in outside will not take this motor once you subtract the wall.
A smaller tube calls for a Sonesse 30, which needs 1.13 in. A tube of 47 mm or more carrying a heavy shade belongs on the Sonesse 50 and LT50 platform. Our Sonesse 28 vs 30 vs 40 vs 50 comparison sets the four sizes side by side.
The crown and drive must match your tube profile too. Somfy makes 400 Series crowns and drives for round and octagonal 40 mm tubes, and our guide to Somfy crowns, drives and brackets explains how to read the tube before you order them.
The six Sonesse 40 versions side by side
The table lists one reference from each family, with the figures Somfy publishes for that reference.
| Version | Example part | Torque and speed | Power | Control | Noise |
|---|---|---|---|---|---|
| RTS | 404S2 (1240380) | 4 Nm (35 in-lb), 36 rpm | 120V AC, 60Hz | RTS radio, 433.420 MHz | 42 dB |
| WT wired | 404S2 (1240377) | 4 Nm (35 in-lb), 36 rpm | 120V AC, 60Hz, 4 wire | Wired wall switch | 42 dB |
| Zigbee | 404S2 (1245920) | 4 Nm (35 in-lb), 36 rpm | 120V AC, 60Hz | Zigbee 3.0, 2.450 GHz | 42 dB |
| RS485 | 406A2 (1240563) | 6 Nm (53 in-lb), 24 rpm | 120V AC, 60Hz | RS485 bus, SDN | 44 dB |
| WireFree RTS | 1240485 | 3 Nm (27 in-lb), 20 rpm | 12V Li-ion, built in | RTS radio, 433.420 MHz | 49 dB |
| WireFree Zigbee | 1245993 | 4 Nm (35 in-lb) | Li-ion, USB-C charging | Zigbee 3.0, 2.450 GHz | 40 dB |
The line-voltage versions come in three torque steps. The 404S2 gives 4 Nm at 36 rpm, the 406A2 gives 6 Nm at 24 rpm, and the 409R2 gives 9 Nm at 14 rpm. The first digits after the 40 name the torque, so a 409R2 lifts more than twice the load of a 404S2 and runs slower doing it. Somfy lists interior blinds, shades and projection screens as the applications for this family.
RTS: the remote-controlled default
Pick the Somfy Sonesse 40 RTS 404S2 Motor with Fast Connector (1240380) when the shade will run from a handheld remote or a battery wall switch. The receiver sits inside the motor, so a Situo, Telis, Smoove or DecoFlex RTS transmitter pairs straight to it with no hub. Somfy rates the 404S2 RTS at 110 W in operation, 0.5 W on standby, IP 44 and 164.05 ft of open-field radio range.
RTS is one-way radio. The remote sends a command and the motor acts on it. Add a TaHoma switch later and the same motor joins app schedules and voice control, which makes RTS the safe choice for a homeowner who wants to start simple. The 406A2 and 409R2 RTS references cover heavier fabric on the same platform.
WT wired: a switch on the wall, no radio
The Somfy Sonesse 40 404S2 WT 120V 4-Wire Motor with Fast Connector (1240377) has no receiver. An electrician runs a four-conductor cable to an up/stop/down wall switch, and the switch drives the motor. Somfy publishes mechanical limits with 40 turns of capacity and an IP 44 rating for the 404S2 WT.
Choose WT when the client wants a hard switch beside the window and no remotes to lose, or when a third-party relay panel will drive the shades. Do not pair RTS remotes to a WT motor. They have nothing to talk to.
Zigbee 3.0: app, voice and two-way feedback
The Somfy Sonesse 40 Zigbee 404S2 with Fast Connector (1245920) runs on 120V AC and talks Zigbee 3.0 at 2.450 GHz. Somfy lists the TaHoma switch as its controller, with Amazon Alexa, Google Home and Apple Home through TaHoma, plus integration guides for Control4, Crestron, Savant, ELAN and Josh.ai among others.
Because the motor is mains powered, it also acts as a Zigbee router and extends the mesh for the devices around it. Somfy publishes electronic limits with 250 turns of capacity, IP 31, 95 W in operation and 656.2 ft of open-field range. The Zigbee line comes in 406A2 and 409R2 torques too. For a deeper look at the radio choice, read our RTS vs Zigbee comparison.
RS485 for SDN and building control
Commercial jobs and large homes with a control system belong on the Somfy Sonesse 40 RS485 406A2 SDN Motor (1240563) or its 404S2 and 409R2 siblings. The motor takes 120V AC for power and a separate RS485 bus for data, which makes it part of the Somfy Digital Network. Somfy names SDN, animeo IP, third-party control systems, wall switches and building management systems as its control paths.
The 406A2 delivers 6 Nm at 24 rpm, draws 0.95 A and 114 W, and runs at 44 dB. Its electronic limits hold 250 turns. An integrator addresses and sets each motor during commissioning, so budget for SDN keypads and a setting tool before the shades go up.
WireFree: no outlet, no wiring
Two battery versions share the 40 mm body. The Somfy Sonesse 40 WireFree RTS (Li-ion) (1240485) carries a built-in 12V lithium-ion battery, 3 Nm at 20 rpm and an RTS receiver with 656.2 ft of open-field range. Somfy pairs it with the Lithium-ion Charger (V2 Head) 9025166 and the WireFree Li-ion Solar Panel Kit 9027294.
The Somfy Sonesse 40 WireFree Zigbee (Li-ion) (USB-C) (1245993) raises the battery motor to 4 Nm, runs at 40 dB and charges through USB-C, a magnetic connection or an optional solar panel. Somfy rates it at about one recharge per year on its reference blind. It joins a TaHoma switch for app and voice control, with 262.48 ft of open-field range.
WireFree suits retrofits where nobody wants to open a wall. Wired versions suit tall, heavy or high-cycle shades where a charge schedule would become a chore.
A quick way to choose
- Remote control and the option to add a hub later: Sonesse 40 RTS.
- A wired switch beside the window, or a relay panel: Sonesse 40 WT.
- App, voice and position feedback through TaHoma: Sonesse 40 Zigbee.
- An SDN or building management project with an integrator: Sonesse 40 RS485.
- No power at the window: WireFree RTS or WireFree Zigbee, sized to stay inside 3 or 4 Nm.
Once you know the version, check torque against fabric weight and drop, confirm the head type on the listing before you order brackets, and match the crown and drive to the tube. Browse the full range of Somfy Sonesse 40 and LS40 motors to compare torques within each version. Install guides for each reference live in our Somfy spec library.
FAQ
What is the minimum tube size for a Somfy Sonesse 40?
Somfy publishes a minimum internal tube diameter of 1.46 in (37 mm) for the Sonesse 40, and the motor body measures 1.57 in at its widest. Measure the inside of the tube, not the outside, since the wall thickness counts. A tube smaller than 1.46 in inside calls for a Sonesse 30, which needs 1.13 in.
Is the Sonesse 40 the same as the LS40?
LS40 is Somfy's older name for its 40 mm interior motor platform, and many listings and installer notes still use it. The Sonesse 40 is the current family on that 40 mm body. Read the part number on the motor label and match it to the Somfy reference when you order a replacement, since torque and control differ by reference.
Can I control a wired Sonesse 40 with a Somfy remote?
Only the RTS and Zigbee versions carry a receiver. A Sonesse 40 WT motor runs from a wired up/stop/down switch and has no radio, so RTS remotes cannot pair with it. An RS485 version takes commands over the SDN bus. If you want remote control on an existing wired circuit, order the RTS version of the same torque.
How much torque does the Sonesse 40 range cover?
The line-voltage Sonesse 40 motors come in 4 Nm at 36 rpm (404S2), 6 Nm at 24 rpm (406A2) and 9 Nm at 14 rpm (409R2). The WireFree RTS version delivers 3 Nm and the WireFree Zigbee version delivers 4 Nm. Heavier shades on larger tubes move to the Sonesse 50 or LT50 range.
Sources: Somfy product pages and e-cat listings for refs 1001636, 1245920, 1240563, 1240485 and 1245993 on somfysystems.com and somfypro.com.
Shade Motors Direct is an authorized source for genuine Somfy motorized window shade, blind, and drapery parts.
