Add unit_of_measurement to climate and water_heater by jhenkens · Pull Request #168747 · home-assistant/core

jhenkens · 2026-04-22T03:22:37Z

Breaking change

Proposed change

Exposes temperature unit for climate and water_heater, with corresponding changes in home-assistant/core, aioesphome, esphome, and esphome-docs, to enable native Fahrenheit measurements on those entities. Usecase is to enable accurate temperature settings on a Fahrenheit hot tub, controlled via RS485-UART. Rather than round tripped from F -> C -> C, with various floating point errors and weirdnesses, this just makes it stay F the entire way and work much more reliably.

Tests still need to be added where appropriate - that's on the todo - but the code has been validated.

When esphome is updated, but core is not, as long as you do not set the temperature unit on a climate/water heater, everything works the same as it currently is. If you do set it, you will convert from F -> "F", as home assistant will think the incoming value from ESPHome is C, without reading the UOM. If ESPHome does not have F specified, it continues to default to C.

When HA is updated, but ESPHome is on an old version, it maintains legacy behavior of treating all climate/water_heaters as using C.

There are still some todo's, namely adding tests in every repo, and some other PR workitems, but the code is working and ready for early review.

Type of change

Dependency upgrade
Bugfix (non-breaking change which fixes an issue)
New integration (thank you!)
New feature (which adds functionality to an existing integration)
Deprecation (breaking change to happen in the future)
Breaking change (fix/feature causing existing functionality to break)
Code quality improvements to existing code or addition of tests

Additional information

This PR fixes or closes issue: fixes #
This PR is related to issue:
Link to documentation pull request:
Link to developer documentation pull request:
Link to frontend pull request:

esphome/aioesphomeapi#1600
esphome/esphome#15815

Checklist

I understand the code I am submitting and can explain how it works.
The code change is tested and works locally.
Local tests pass. Your PR cannot be merged unless tests pass
There is no commented out code in this PR.
I have followed the development checklist
I have followed the perfect PR recommendations
The code has been formatted using Ruff (ruff format homeassistant tests)
Tests have been added to verify that the new code works.
Any generated code has been carefully reviewed for correctness and compliance with project standards.

If user exposed functionality or configuration variables are added/changed:

Documentation added/updated for www.home-assistant.io

If the code communicates with devices, web services, or third-party tools:

The manifest file has all fields filled out correctly.
Updated and included derived files by running: python3 -m script.hassfest.
New or updated dependencies have been added to requirements_all.txt.
Updated by running python3 -m script.gen_requirements_all.
For the updated dependencies a diff between library versions and ideally a link to the changelog/release notes is added to the PR description.

To help with the load of incoming pull requests:

I have reviewed two other open pull requests in this repository.

(cherry picked from commit 82dec48)

home-assistant · 2026-04-22T03:22:47Z

Hey there @jesserockz, @kbx81, @bdraco, mind taking a look at this pull request as it has been labeled with an integration (esphome) you are listed as a code owner for? Thanks!

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Copilot

Pull request overview

This PR updates the ESPHome integration’s climate and water_heater entities to expose the temperature unit_of_measurement from the device’s static info, enabling native Fahrenheit (and other units) end-to-end.

Changes:

Add TemperatureUnit → UnitOfTemperature mapping for ESPHome climate entities.
Add TemperatureUnit → UnitOfTemperature mapping for ESPHome water_heater entities.
Set _attr_temperature_unit from ESPHome static info during entity info updates.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 4 comments.

File	Description
`homeassistant/components/esphome/climate.py`	Maps ESPHome-reported temperature units onto HA’s climate entity unit handling.
`homeassistant/components/esphome/water_heater.py`	Maps ESPHome-reported temperature units onto HA’s water heater entity unit handling.

Copilot · 2026-04-22T03:26:35Z

+_WATER_HEATER_TEMPERATURE_UNIT_MAP: dict[TemperatureUnit, UnitOfTemperature] = {
+    TemperatureUnit.CELSIUS: UnitOfTemperature.CELSIUS,
+    TemperatureUnit.FAHRENHEIT: UnitOfTemperature.FAHRENHEIT,
+    TemperatureUnit.KELVIN: UnitOfTemperature.KELVIN,
+}


Deduplicate the TemperatureUnit→UnitOfTemperature mapping by reusing a shared constant (instead of defining a second map here) to keep behavior consistent across ESPHome platforms.

Copilot · 2026-04-22T03:26:35Z

+        self._attr_temperature_unit = _CLIMATE_TEMPERATURE_UNIT_MAP[
+            static_info.temperature_unit
+        ]


Add unit tests that validate the entity’s temperature unit is set from the ESPHome static info (e.g., Fahrenheit) and that service calls/state attributes behave correctly with that unit.

Copilot · 2026-04-22T03:26:35Z

+        self._attr_temperature_unit = _WATER_HEATER_TEMPERATURE_UNIT_MAP[
+            static_info.temperature_unit
+        ]


Add unit tests that validate the water heater’s temperature unit is set from the ESPHome static info (e.g., Fahrenheit) and that min/max/step and service calls are interpreted in that unit.

Copilot · 2026-04-22T03:26:36Z

+_CLIMATE_TEMPERATURE_UNIT_MAP: dict[TemperatureUnit, UnitOfTemperature] = {
+    TemperatureUnit.CELSIUS: UnitOfTemperature.CELSIUS,
+    TemperatureUnit.FAHRENHEIT: UnitOfTemperature.FAHRENHEIT,
+    TemperatureUnit.KELVIN: UnitOfTemperature.KELVIN,
+}


Deduplicate the TemperatureUnit→UnitOfTemperature mapping by moving it to a shared constant (e.g., in the ESPHome integration module) so climate and water_heater can’t drift in behavior over time.

bdraco · 2026-04-22T03:37:27Z

Would be good to do a separate PR to bump aioesphomeapi first

jhenkens · 2026-04-22T04:08:34Z

Would be good to do a separate PR to bump aioesphomeapi first

#168749

Copilot

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

Copilot · 2026-04-22T04:16:12Z

        self._feature_flags = ClimateFeature(
            static_info.supported_feature_flags_compat(self._api_version)
        )
+        self._attr_temperature_unit = TEMPERATURE_UNIT_MAP[static_info.temperature_unit]


Add test coverage that sets temperature_unit in ClimateInfo (e.g., Fahrenheit) and asserts the entity reports the correct temperature unit and that service calls pass the raw temperature values without unintended conversion.

Copilot · 2026-04-22T04:16:12Z

        """Set attrs from static info."""
        super()._on_static_info_update(static_info)
        static_info = self._static_info
+        self._attr_temperature_unit = TEMPERATURE_UNIT_MAP[static_info.temperature_unit]


Add test coverage that sets temperature_unit in WaterHeaterInfo (e.g., Fahrenheit) and asserts the entity exposes the correct temperature unit and that async_set_temperature forwards the intended value in that unit.

Copilot

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated no new comments.

Co-authored-by: J. Nick Koston <nick+github@koston.org>

Copilot

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Copilot · 2026-04-22T05:42:53Z

        """Set attrs from static info."""
        super()._on_static_info_update(static_info)
        static_info = self._static_info
+        self._attr_temperature_unit = TEMPERATURE_UNIT_MAP.get(static_info.temperature_unit, UnitOfTemperature.CELSIUS)


Import UnitOfTemperature (or avoid referencing it) so _on_static_info_update doesn’t raise NameError when setting _attr_temperature_unit.

Copilot

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated no new comments.

jhenkens · 2026-04-23T02:27:42Z

Retested this change with my custom build of ESPHome - easier now that aioesphomeapi is merged - and can confirm this still works as desired.

…-to-climate-and-water-heater

…and-water-heater' into add-temperature-unit-to-climate-and-water-heater

Copilot

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

+        (
+            3,
+            UnitOfTemperature.CELSIUS,
+        ),  # unknown value maps to Celsius via aioesphomeapi


+        (
+            3,
+            UnitOfTemperature.CELSIUS,
+        ),  # unknown value maps to Celsius via aioesphomeapi


Add unit_of_measurement to climate and water_heater

d333329

(cherry picked from commit 82dec48)

Copilot AI review requested due to automatic review settings April 22, 2026 03:22

home-assistant Bot added cla-signed integration: esphome new-feature small-pr PRs with less than 30 lines. Top 100 Integration is ranked within the top 100 by usage Top 200 Integration is ranked within the top 200 by usage Top 50 Integration is ranked within the top 50 by usage labels Apr 22, 2026

home-assistant Bot assigned jesserockz, kbx81 and bdraco Apr 22, 2026

home-assistant Bot added the Quality Scale: platinum label Apr 22, 2026

Copilot started reviewing on behalf of jhenkens April 22, 2026 03:23 View session

jhenkens mentioned this pull request Apr 22, 2026

Add temperature unit for climate and water heater #168261

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Copilot AI reviewed Apr 22, 2026

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Move map to const

4c5d595

Merge branch 'dev' into add-temperature-unit-to-climate-and-water-heater

c52b56e

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jhenkens added 2 commits April 21, 2026 21:17

Add basic tests

32d39b4

Not sure how prek missed this one line

362921b

Copilot AI review requested due to automatic review settings April 22, 2026 04:25

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Comment thread homeassistant/components/esphome/water_heater.py Outdated

Copilot AI reviewed Apr 22, 2026

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Add dictionary .get fallback

20491e3

Co-authored-by: J. Nick Koston <nick+github@koston.org>

Copilot AI review requested due to automatic review settings April 22, 2026 05:39

Copilot started reviewing on behalf of jhenkens April 22, 2026 05:40 View session

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jhenkens and others added 2 commits April 21, 2026 22:45

Remove None from const

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Make lookups safer

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Copilot AI review requested due to automatic review settings April 22, 2026 05:55

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Merge branch 'dev' into add-temperature-unit-to-climate-and-water-heater

95b24f1

jhenkens added 2 commits May 2, 2026 09:57

Merge remote-tracking branch 'upstream/dev' into add-temperature-unit…

54d066b

…-to-climate-and-water-heater

Merge remote-tracking branch 'origin/add-temperature-unit-to-climate-…

d098f2c

…and-water-heater' into add-temperature-unit-to-climate-and-water-heater

Copilot AI review requested due to automatic review settings May 2, 2026 17:00

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jhenkens commented Apr 22, 2026

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