Daikin Altherma 4 Modbus for Home Assistant (Marketplace integration)

Installs: 58 sharing analytics
GitHub stars: 32
Connection: Works locally
Upkeep: Updated in the last 6 months
Version: v0.7.3, October 25, 2026
Category: Climate, Heat pumps and air conditioning
Kind: Marketplace integration
Brand: Daikin
Needs: Needs the Marketplace (HACS on 2026.10 and older)
Domain: ha_daikin_altherma4_modbus
Source: github.com/joklee/ha_daikin_altherma4_modbus
Issues: Report an issue

Independent directory, made by the developer of Vulpo. Not affiliated with Home Assistant or the Open Home Foundation.

About

Daikin Altherma 4 Modbus connects Daikin Altherma 4 heat pumps (EPSX series) to Home Assistant over Modbus TCP. It runs locally and is set up in the UI with the heat pump's host, port, unit ID and polling intervals. It adds sensors and binary sensors for temperatures, power and operating states, plus climate entities, numbers, selects and switches for heating zones, domestic hot water and operation modes. Actions cover setting the operation mode, quiet mode, Smart Grid mode, power limit, room setpoints and weather-dependent offsets, and starting a one-time domestic hot water heat-up that fires an event when finished. It uses Home Assistant's shared Modbus connection, offers a demo mode and an optional external power sensor, and can raise repair notices when the connection is lost or the unit reports an abnormality.

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Supports

Works locally Talks to your devices on your own network. No vendor cloud in between.
From the Marketplace Installed through the Marketplace, formerly HACS.
Actively maintained Its author released or pushed a change in the last six months.

Provides

Climate
Switches
Sensors

Setting it up

Install it from the Marketplace and restart Home Assistant, then add it under Settings, Devices and services.

Daikin Altherma 4 Modbus

HostIP address or hostname of the Daikin Altherma heat pump
PortModbus TCP port (default: 502)
Scan IntervalScan interval in seconds for normal data
Slow Scan IntervalScan interval in seconds for slow data
External Electric Power Sensor Entity IDOptional entity ID for external electric power sensor
Demo ModeEnable demo mode without real connection
Unit IDModbus unit address (slave ID) of the heat pump, usually 1.

Also asked when signing in again and changing the connection.

After setup

Scan IntervalScan interval in seconds for normal data
Slow Scan IntervalScan interval in seconds for slow data
External Electric Power Sensor Entity IDOptional entity ID for external electric power sensor
Demo ModeEnable demo mode without real connection

Texts from the code of joklee/ha_daikin_altherma4_modbus.

Entities

Binary sensorsConnection active, Device reachable, Circulation pump running, Compressor run, Booster heater run, Disinfection operation, Defrost/Restart, Hot start, Disinfection state, Holiday mode, Shut-off valve, Backup heater relay 1, and 21 more
ClimateHeating Thermostat Control, DHW Single Heat-up Thermostat Control, DHW Booster Thermostat Control
NumbersLeaving water Main Heating setpoint, Leaving water Main Cooling setpoint, Room thermostat control Heating setpoint Main, Room thermostat control Cooling setpoint Main, DHW reheat setpoint, DHW boost setpoint (Powerful), DHW Single heat-up setpoint (Manual), Weather-dependent mode Main LWT Heating setpoint offset, Weather-dependent mode Main LWT Cooling setpoint offset, Imposed power limit, Leaving water Add Heating setpoint, Leaving water Add Cooling setpoint, and 4 more
SelectsOperation mode, Quiet mode operation, Smart Grid operation mode, Weather-dependent mode Heating Main, Weather-dependent mode Cooling Main, Thermostat request Main, Thermostat request Add, DHW mode setting
SensorsAbnormality decoded, Last read, Last write, Read errors, Connection state, Write errors, Consecutive failures, Unit abnormality, Unit abnormality code, Unit abnormality sub code, Circulation pump running, Compressor run, and 59 more
SwitchesDomestic Hot Water, Main zone, Additional zone, Space heating/cooling ON/OFF, DHW booster mode ON/OFF (Powerful), DHW Single heat-up ON/OFF (Manual), Execute model restart now

Actions

Set operation modeSet the heat pump operation mode (Off, Heating, Cooling).Fields: Config entry, Operation mode
Set DHW stateEnable or disable Domestic Hot Water.Fields: Config entry, State
Set main zone stateEnable or disable the main zone.Fields: Config entry, State
Set additional zone stateEnable or disable the additional zone.Fields: Config entry, State
Set Smart Grid modeSet the Smart Grid operation mode for energy management.Fields: Config entry, Smart Grid mode
Set quiet modeSet the quiet/night operation mode.Fields: Config entry, Quiet mode
Set DHW booster modeEnable or disable the DHW booster (Powerful) mode.Fields: Config entry, Booster mode
Set DHW single heat-upStart or stop the DHW one-time heat-up request, with an optional setpoint.Fields: Config entry, Single heat-up, Setpoint
Start DHW single heat-upHeat domestic hot water once to a target temperature. Enables DHW automatically when it is off and restores it afterwards. Returns immediately; a background task stops the request on target or timeout and fires ha_daikin_altherma4_modbus_dhw_single_heatup_finished.Fields: Config entry, Target temperature, Timeout, Hysteresis
Set power limitSet the imposed power limit in kW (0-20).Fields: Config entry, Power limit
Set heating offsetSet the weather-dependent heating offset in K (-10 to +10).Fields: Config entry, Offset
Set cooling offsetSet the weather-dependent cooling offset in K (-10 to +10).Fields: Config entry, Offset
Set room heating setpointSet the room thermostat heating setpoint in °C (12-30).Fields: Config entry, Setpoint
Set room cooling setpointSet the room thermostat cooling setpoint in °C (12-35).Fields: Config entry, Setpoint
Set additional zone setpointSet the additional zone setpoint in °C (3-85).Fields: Config entry, Setpoint
Refresh connectionRefresh the Modbus connection for the config entry.Fields: Config entry

Troubleshooting

DiagnosticsDownloads a diagnostics file to attach to a bug report.
Repair noticesNotices it can show in Settings, Repairs:Connection lost to Daikin Altherma 4, Daikin Altherma 4 reports abnormality

From the README

Short description: This integration connects Daikin Altherma 4 heat pumps (EPSX series) to Home Assistant via Modbus TCP. It provides comprehensive monitoring of temperatures, power consumption, and operating states, as well as control of heating zones, domestic hot water, and operation modes.
⚠️ WARNING: Use at your own risk! This integration modifies heat pump settings. Incorrect configuration may damage your equipment or void your warranty. Always consult the official Daikin documentation before making changes.

From the README of joklee/ha_daikin_altherma4_modbus, GNU GPL v3.0. Shortened.