Lennox L40 Smart Thermostat: Matter Compatibility Reference

The Lennox L40 Smart Thermostat is a Wi-Fi Matter thermostat for single-stage heating and cooling systems, including dual-fuel setups. Lennox added Matter support through a firmware update: MatterAlpha's December 12, 2025 report says firmware 4.38 or higher allows L40 owners to generate a Matter pairing code on the thermostat. MatterCheck's type-level thermostat matrix shows pairing and control as Yes for Apple Home, Google Home, Amazon Alexa, SmartThings, Home Assistant, Homey, and Hubitat. In that L40 update report, only Google Home, Samsung SmartThings, Apple Home, and Amazon Alexa are named as ecosystems owners can use after scanning the QR code.

Lennox L40 Matter connection and CSA certification

The CSA-IOT product page for the Lennox L40 Smart Thermostat lists Wi-Fi as transport, Matter 1.3 as the specification version, firmware 04.38.0087, hardware version 0004, certificate ID CSA25B3CMAT47758-24, certified date 10/14/2025, product ID 0x0002, vendor ID 0x1356, and primary device type ID 0x0301. The CSA DCL record adds part number 108275 for vendor ID 4950 and product ID 2. Because this is a Wi-Fi Matter device, not Thread, no Thread border router is required; MatterCheck's Matter Thread vs Wi-Fi guide covers that division.

Lennox L40 platform compatibility table

The table below is MatterCheck's type-level thermostat matrix, not a hands-on test of this L40 SKU. Consult the Matter thermostat support guide for ecosystem-level control notes.

MatterAlpha's December 12, 2025 L40 and S40 update report names Google Home, Samsung SmartThings, Apple Home, and Amazon Alexa as supported ecosystems for this thermostat. Home Assistant, Homey, and Hubitat show Yes at the type level in MatterCheck's matrix, but the provided pages do not contain a dated hands-on L40 report for those three platforms.

How the L40 platform matrix compares

All seven platforms in the thermostat type matrix show Yes for pairing and Yes for control. The split is in starts-automations support: Apple Home and Amazon Alexa are Unknown in the matrix, while Google Home, SmartThings, Home Assistant, Homey, and Hubitat are Yes. All seven platforms are Yes for being controlled by automations. Product-specific sourcing narrows the named L40 ecosystem list to Google Home, Samsung SmartThings, Apple Home, and Amazon Alexa. The Matter multi-admin sharing guide explains how to pair a device into more than one ecosystem.

Lennox L40 setup, app, and customer reports

L40 Wi-Fi and Matter pairing steps

• Wi-Fi setup: Lennox's L40 support article says to go to Menu > Settings > Wi-Fi, slide Wi-Fi ON, press "Not Connected", choose the network, enter the password, and press Join.
• Account and app: Lennox says to create or sign in from the thermostat, then download the "Lennox Smart Thermostat App" from the Apple App Store or Google Play. The L40 support page sends users to Menu > User Account; the L40 product page calls the phone/tablet app the Lennox Home app.
• Matter pairing: MatterAlpha says the thermostat must be on firmware 4.38 or higher and on the same Wi-Fi network as the phone or controller. Tap Matter Settings, then Make Discoverable, then Show Code, and scan the QR code with the preferred ecosystem. Lennox's support FAQ repeats the 4.38 and same Wi-Fi requirements; the thermostat shows a "Pairing Successful" message after pairing.

L40 install manuals and support materials

Lennox's support center page for the L40 lists an L40 Quick Start Guide and an L40 User Guide as the starting documents. The CSA DCL record does not provide a user manual URL.

L40 specs, price, and reported limits

• Heating/cooling fit: The CSA-IOT product page says the L40 has universal compatibility with single-stage heating and cooling systems, including dual-fuel setups. MatterAlpha describes the L40 as Lennox's entry-level model with a four-color touchscreen and support for single-stage systems.
• Automation and energy features: Lennox lists Schedule IQ Technology, Smart Away geo-fencing, auto changeover, smooth setback recovery up to 2 hours before programmed time, customizable reminders, and monthly energy reports. The L40 support page says Smart Away must be on for Schedule IQ to function.
• Voice and smart home: Lennox's L40 product page names Amazon Alexa, Google Assistant, Control4, and Building36. CSA-IOT names Amazon Alexa, Google Assistant, and Control4. Lennox support says smart home integration is now enabled by Matter.
• Warranty: Lennox lists a 5-year limited warranty and ENERGY STAR qualification for the L40.
• Price: MatterAlpha reports the L40 as $$ in Lennox's price guide and says a third-party Amazon listing was $249 as of December 12, 2025.
• Owner review by Basya, June 25, 2026: On Lennox's product page, Basya rated the L40 4/5 after a software update. Most functions moved from the app to the thermostat, but schedule editing still was not available on the thermostat, and the screen saver dim mode no longer dimmed correctly.
• Owner review by StevenL, October 15, 2025: On Lennox's product page, StevenL rated features 5/5 and said installation was easy, setup was intuitive, and the setup did not time out.

No page in this check covers an L40 that will not power on or turn on; the official L40 support material covers Wi-Fi, account, app, and Matter pairing rather than a dead display.

Lennox L40 Smart Thermostat buy or skip verdict

• Buy if you want a Wi-Fi Matter thermostat with on-device Matter pairing after firmware 4.38, Schedule IQ, Smart Away geo-fencing, and a 5-year limited warranty.
• Buy if your system is single-stage heating/cooling or dual-fuel, which the CSA-IOT page says the L40 supports.
• Skip if editing schedules from the thermostat itself is a hard requirement: the June 25, 2026 Lennox owner review says that remained missing after the update.
• Skip if you need product-specific L40 evidence for Home Assistant, Homey, or Hubitat; the provided pages leave those platforms to MatterCheck's type-level thermostat matrix.