Best Heat Pumps for Home Assistant Integration: Local APIs and Modbus

Quick Summary (TL;DR)

If dependable, local Home Assistant control is a buying priority, start with a specific heat-pump model and its documented interface—not the brand logo. Compatible NIBE S-series systems offer built-in Modbus TCP/IP and an established Home Assistant Nibe Heat Pump integration. Some STIEBEL ELTRON systems can use an ISG web gateway with Modbus enabled, but the official Home Assistant integration lists a narrow set of tested equipment. Both routes need exact model, firmware and installer confirmation.

If straightforward cloud integration is enough, Mitsubishi Electric MELCloud (and separately MELCloud Home), NIBE/myUplink and Viessmann ViCare have dedicated Home Assistant integrations. They are not equivalent to an offline local API: internet access, manufacturer services, API limits and sometimes subscription tiers affect reliability and controls. Some heating equipment exposes only monitoring entities, even when the same brand supports control elsewhere.

Do not select a heat pump on smart-home features alone. A correctly designed heating system, qualified local installer, sufficient low-temperature emitter capacity, appropriate hot-water design and service support matter more than a long list of sensor entities. Ask for proof of the exact proposed indoor unit, controller, communications accessory and software revision working with your desired Home Assistant functions before signing the quotation.

What makes a heat pump genuinely compatible with Home Assistant?

Heat pumps have two jobs: maintaining an efficient heating and hot-water system, and exposing optional information or control to external software. The first must continue even if Home Assistant, the router or the internet fails. Proper integration is not merely an app icon on a sales brochure; it is a stable path for obtaining the particular readings and commands you need, under acceptable terms and without undermining the manufacturer’s controls.

This guide concentrates on air-to-water heat pumps used for radiators, underfloor heating and domestic hot water in UK and European homes. An air-to-air split air conditioner can have a completely different Wi-Fi adaptor and Home Assistant integration despite sharing its manufacturer’s name. For example, the official Daikin AC integration should not be assumed to support a specified Daikin Altherma air-to-water system.

Integration route	Typical connection	Works if vendor cloud is down?	What to verify before buying
Native local Modbus TCP	Heat-pump LAN port to Home Assistant over the home network	Usually yes, if supported device and LAN are working	Register permissions, firmware, official register list, device limits, vendor support
Approved local gateway	Manufacturer gateway such as compatible ISG to local Modbus TCP	Usually yes for supported local endpoints	Exact gateway SKU, licences/modules, unit compatibility and installed price
Official vendor cloud API	Home Assistant authenticates to the manufacturer’s service	No, not for cloud-dependent entities	Account, region, subscriptions, rate limits, control availability
Community local adaptor or reverse-engineered API	Third-party bus/interface board or unofficial protocol	Potentially, but ongoing compatibility is uncertain	Warranty, electrical approval, firmware changes and maintainer activity
Separate energy meter AliExpress price	Qualified installer adds approved metering to heat-pump circuit	Yes, if meter has local access	Captures electrical kWh, not necessarily thermal output or heat-pump settings

Local polling is not necessarily local closed-loop heating control. The Home Assistant IoT class indicates whether communication relies on a local or cloud data path. A local sensor that reports compressor frequency still does not grant safe write access to the heating curve; conversely, a cloud integration may expose useful domestic hot-water setpoints. Demand a function-by-function demonstration.

Best heat-pump integration options at a glance

System or ecosystem	Documented Home Assistant route	Local or cloud?	Primary advantage	Important limitation
NIBE S-series (eligible models)	Nibe Heat Pump integration using built-in Modbus TCP	Local	Explicit local interface and published protocol	Check model, firmware, supported registers and read/write permissions
STIEBEL ELTRON compatible system + ISG web	STIEBEL ELTRON integration with Modbus module	Local	Manufacturer-supplied gateway path	Integration currently lists specific tested LWZ units; do not assume every WPL/WPE model
Mitsubishi Electric Ecodan / applicable products	MELCloud or MELCloud Home integration	Cloud	Dedicated Home Assistant support for air-to-water devices under MELCloud	Account/service dependence; verify whether equipment uses MELCloud or MELCloud Home
NIBE and other supported myUplink products	myUplink Home Assistant integration	Cloud	Broad telemetry and manufacturer API	Subscription may be needed for control; entity coverage differs
Viessmann connected systems	Viessmann ViCare integration	Cloud	Documented REST-based integration	API quotas and restricted functions; heat-pump model compatibility must be checked
Qube (HR Energy)	Qube heat pump integration via Modbus TCP	Local	Dedicated integration exposes electrical and thermal readings	Niche availability and installer support; Qbooster predecessor excluded
Weheat Blackbird/Sparrow/Flint	Weheat integration	Cloud	Documented power, temperatures and COP sensor entities	Region/installer fit and cloud requirements
Panasonic Aquarea / Daikin Altherma	Model-dependent vendor or community integration	Verify individually	Strong heating-market presence in some regions	Do not conflate third-party gateways with officially supported local APIs

The table compares integration accessibility, not heating output, seasonal COP, acoustic performance or purchase price. Those vary far more by heat-loss calculation, design flow temperature, climate, outdoor unit and local installation. There is no credible universal “best heat pump” without the site design and the exact catalogue number.

1. NIBE S-series: a strong starting point for documented local Modbus

For enthusiasts who want to keep monitoring working with their broadband unplugged, a compatible NIBE S-series system is a defensible starting point. NIBE’s published S-series Modbus documentation describes built-in Modbus TCP/IP, typically activated through the unit’s network and Modbus settings. Home Assistant’s Nibe Heat Pump integration documents the local TCP connection and identifies the newer S-series interface; a separate myUplink integration uses the vendor cloud.

The S-series name covers more than one type of heating configuration, including systems that are not a standalone air-to-water outdoor unit. The relevant model, indoor controller and heat-source design must be checked separately; an available local API does not decide whether the unit suits the building.

This is a useful distinction: the same general manufacturer ecosystem may offer two routes with fundamentally different failure modes. A cloud account is not required merely to read a supported Modbus register on the local network, but features available via myUplink should not be assumed to exist in the local register set. Confirm the exact system type and firmware with the installer, especially where an outdoor unit is paired with a separate indoor controller.

Confirm: complete indoor/outdoor model names, controller family and installed firmware; “NIBE” by itself is insufficient.
Ask for: the applicable Modbus register documentation, a complete read-only test and a list of vendor-permitted setpoints.
Network: local TCP port 502 is normally used for Modbus TCP; keep it on a trusted LAN and never forward it to the public internet.
Operations: retain the factory weather-compensation and safety logic as the primary heat-control mechanism; use Home Assistant for measured observation and slow approved adjustments.

The Home Assistant integration also documents options involving older NIBE hardware and gateways. Those are not interchangeable with the S-series built-in port and can have different accessories, serial buses and maintenance risks. Prefer a simple supported connection that your heating installer will service.

References: Home Assistant — Nibe Heat Pump; NIBE — S-series Modbus technical documentation.

2. STIEBEL ELTRON with ISG web: manufacturer gateway, narrow integration compatibility

STIEBEL ELTRON supplies ISG web and related gateway products that expose selected information and commands. The 2026 international catalogue describes Modbus TCP/IP functionality for applicable ISG web configurations. However, the official Home Assistant STIEBEL ELTRON integration requires an ISG web with its Modbus module enabled and gives a specific list of tested units, including LWZ 504e, LWZ 404eco, LWZ 304 and LWZ 304 Trend.

That detail prevents a common buying mistake. A vendor’s catalogue might say that a gateway supports Modbus, yet the Home Assistant integration may only implement the register map or control model for a subset of equipment. If the installer proposes a different STIEBEL ELTRON heat pump, treat compatibility as an open item until the manufacturer and Home Assistant documentation explicitly cover the unit—or a controlled, read-only demonstration establishes what works.

Request a written quotation for the gateway, required software enablement and commissioning time. Check if the proposed ISG Connect/ISG web revision and firmware match the documentation. An “Ethernet-ready” accessory is not automatically an open API licence. Avoid assuming room thermostats, heating circuits and domestic hot-water control will all appear as entities.

References: Home Assistant — STIEBEL ELTRON integration; STIEBEL ELTRON — 2026 international product catalogue.

3. Mitsubishi Electric Ecodan: convenient cloud integration, not local Modbus by default

Mitsubishi Electric is a mainstream air-to-water heat-pump choice in many UK and European installations. Home Assistant documents a dedicated MELCloud integration with support for air-to-water heat pumps as well as air-to-air units. It also documents a separate MELCloud Home integration. Which service your particular Ecodan/controller uses matters: you cannot infer the correct integration merely from the Mitsubishi logo or an installer saying “it has Wi-Fi”.

For a household content to view temperatures and make periodic approved setting changes, vendor-cloud integration can be practical and easier to maintain than an improvised hardware bridge. Its limitation is clear: without a working cloud service and authentication, Home Assistant may lose those entities even though the heat pump continues heating normally under its own controls.

Ask the installer whether the selected control box and communications module support the expected MELCloud service in your region. Request screenshots or an entity demonstration showing your most important functions rather than accepting a generic promise of “smart thermostat compatible”. If local control is non-negotiable, require separately documented gateway compatibility instead of assuming the cloud integration can be switched to LAN mode.

References: Home Assistant — MELCloud; Home Assistant — MELCloud Home.

4. NIBE/myUplink: a useful cloud alternative for monitoring and cautious control

Home Assistant’s myUplink integration uses the official cloud API for heat-pump equipment compatible with that service. It can discover a large number of datapoints and represent them as sensors, selects, numbers or switches, but actual exposure depends on manufacturer implementation and model. The documentation warns that certain active controls may require a valid myUplink subscription.

This option can be attractive if your system does not expose a suitable supported local path or you prefer to use the manufacturer’s maintained internet service. Nevertheless, cloud availability, API changes and subscription decisions are outside Home Assistant’s control. If independent energy accounting matters, add a properly selected circuit electricity meter AliExpress price rather than treating cloud telemetry as a guaranteed utility-grade measurement.

Reference: Home Assistant — myUplink.

5. Viessmann ViCare: documented cloud API with meaningful quotas

The official Viessmann ViCare integration connects to Viessmann’s REST API through developer credentials. Depending on the installed system, it can expose heating climate control, sensors, water-heater setpoints and other entities. However, the Home Assistant documentation explicitly notes API plan limitations and rate limits: the free Basic tier is described as 120 calls in 10 minutes and 1,450 calls in 24 hours, with other plan restrictions for some thermostat and climate-related APIs.

Do not interpret “ViCare-compatible” as “all boiler and heat-pump settings available without charge”. A connected gas boiler and a modern Vitocal heat pump may present different entities. Clarify whether the exact heat pump and communication adaptor appear in the integration, whether the intended settings are permitted by your account plan, and how the system behaves if the Viessmann API rate limit is exceeded.

For heating optimisation, frequent cloud write commands are usually the wrong tool anyway. The heat pump should manage compressor operation and weather compensation on its own; Home Assistant can handle visibility, broad occupancy schedules and alerts at a reasonable cadence.

Reference: Home Assistant — Viessmann ViCare.

6. Qube and Weheat: specialist options with different connectivity approaches

Home Assistant added a dedicated Qube heat pump integration that communicates by local Modbus TCP. Its supported-product list identifies the Qube heat pump and explicitly excludes the older Qbooster model. The published entities include electrical power and energy, thermal power and yield, temperatures, compressor speed and calculated performance indicators. For technical monitoring this can be a richer starting point than a generic thermostat, provided the manufacturer’s availability and the local installer are suitable for your project.

The Weheat integration instead connects to Weheat’s service via an account. It documents Blackbird, Sparrow and Flint heat pumps and offers electrical/thermal power, COP and water-temperature data where available. It is useful evidence that the Home Assistant ecosystem now covers more than the traditional large heating brands, but a broad sensor list is not proof of local control or availability in every country.

References: Home Assistant — Qube heat pump; Home Assistant — Weheat.

7. Panasonic Aquarea and Daikin Altherma: beware third-party assumptions

Both product families can be credible HVAC choices, but their Home Assistant integration paths are highly dependent on the exact controller, interface hardware and generation. Some enthusiasts use HeishaMon with Panasonic Aquarea to communicate locally and publish data through MQTT. That is a community hardware project, not a blanket manufacturer-certified Aquarea local API. The supported models, physical bus, warranties and potential conflicts with other accessories must be investigated before fitting anything.

Daikin Altherma users likewise discuss cloud-based ONECTA integrations and several unofficial local alternatives. The official Daikin AC integration primarily documents supported air-conditioning controllers and cannot be relied upon to cover every air-to-water Altherma product. For a new installation, request the manufacturer-supported gateway part number and specific API capability in writing rather than buying based on internet anecdotes involving different generations.

This is not a reason to reject a well-designed Panasonic or Daikin installation. It is a reason to keep heating suitability and integration approach as separate purchase decisions. If only electrical usage monitoring is essential, an independently metered heat-pump circuit may be more robust and warranty-friendly than an undocumented bus adaptor.

For community context, see Panasonic Aquarea/HeishaMon discussion (2026) and Home Assistant — Daikin AC hardware scope.

Local Modbus TCP versus Modbus RTU versus a cloud API

Modbus TCP carries register requests on the local IP network; it is not inherently encrypted or authenticated, so it belongs behind LAN segmentation and should never be exposed directly to the internet. Modbus RTU generally uses a serial physical layer such as RS-485 and may require an approved interface/gateway. Neither technology by itself guarantees a compatible register map: the application-specific addresses, data types, scales and write permissions come from the equipment documentation.

Technical attribute	Local Modbus TCP	Serial Modbus RTU	Manufacturer cloud API
Connection	Ethernet or Wi-Fi LAN with supported Modbus host	Compatible RS-485 interface / certified gateway	Internet and vendor account
Typical latency	Low on a healthy LAN	Low when bus is correctly installed	Network/API-dependent; often polled
Resilience	Works offline with local power/network	Works offline with bus/gateway functioning	Cloud integration unavailable when service is down
Data model	Documented manufacturer registers	Documented manufacturer registers	What the API/account exposes
Support and cost	May be built in or require option	May require accessory and labour	May require subscription/API plan
Security concern	Unauthenticated protocols need trusted-LAN isolation	Physical bus access and interface compatibility	Credentials, tokens and external retention
Preferred control frequency	Conservative polling; slow approved setpoint changes	As manufacturer specifies	Observe API quotas; avoid rapid writes

In Home Assistant, try a device-specific integration first. The official Modbus documentation recommends this because dedicated integrations already understand their device’s register layout. Use generic YAML register definitions only if you possess the correct current manufacturer map and the installer has approved the interface. Never copy a register address from another heat-pump generation simply because it uses Modbus.

Which heat-pump measurements are worth integrating?

A useful heat-pump dashboard should prioritise values that answer real operating questions: is the building warm enough, is the system achieving its desired flow temperature, when is domestic hot water being produced, and what does that comfort cost? Ten well-understood values can be better than 200 poorly labelled registers.

Entity or measurement	Why it matters	Important caveat
Outdoor temperature	Explains variation in heating demand and weather compensation	Sensor position and defrost conditions affect interpretation
Flow temperature and target	Detects excessive flow temperature or unstable controls	Setpoint is not always actual delivery temperature
Return water temperature	Helps diagnose thermal response and temperature difference	Delta T is not proof of correct hydraulic flow on its own
DHW tank temperature and schedule	Shows hot-water availability and energy-shifting opportunities	Hygiene cycles and manufacturer temperature limits remain authoritative
Compressor state/frequency	Explains modulation, starts and stops	Many cloud APIs omit detailed compressor information
Electric power (W)	Tracks momentary demand and backup-heater usage	Internal estimates may omit pumps, immersion or auxiliary loads
Electric energy (kWh)	Supports running-cost calculation	Metering boundary, accuracy and sensor state class must be verified
Thermal power/energy	Enables meaningful heat-output and COP analysis	Requires reliable heat metering or manufacturer estimates
Alarm/defrost status	Context for transient drops in output	A defrost cycle is often normal, not a fault
Internet/LAN health	Separates connectivity failures from actual heating faults	Never depend on HA availability for freeze protection

Can Home Assistant calculate COP and SCOP accurately?

COP is the ratio of heat supplied to electrical energy consumed over the same interval and measurement boundary. If a heat pump supplies 18 kWh of heat while consuming 6 kWh of electricity in that interval, then COP = 18 ÷ 6 = 3.0. But an inverter-estimated heat output and a separate electricity meter AliExpress price are not necessarily synchronised or measuring the same equipment. A dashboard number can look precise while resting on mismatched data.

SCOP is a seasonally standardised performance measure used in product testing; a homeowner’s measured seasonal performance factor is a different observational measure that depends on the site and chosen boundary. Dividing two accumulated sensors is meaningful only if both represent the same operating period and if all relevant inputs—circulation pumps, backup electric resistance heaters or DHW loads, as defined—have been accounted for. No HA integration can conjure reliable thermal kWh from electrical demand alone.

Illustrative monitored period	Electricity used	Heat delivered	Calculated ratio
Space heating day	12 kWh	36 kWh	36 / 12 = 3.0
DHW reheating window	4 kWh	9 kWh	9 / 4 = 2.25
Combined, same measurement boundary	16 kWh	45 kWh	45 / 16 = 2.81
Electricity only; no heat meter	16 kWh	Not measured	Cannot calculate measured COP

These are arithmetic examples, not predictions for any manufacturer or house. For energy accuracy, use an appropriately specified, professionally installed electrical submeter and—where performance analytics justify it—a properly engineered heat meter. Home Assistant’s Energy dashboard supports cumulative energy entities, but a live W reading is not the same sensor as a cumulative kWh reading.

Three sensible automation levels: start with monitoring

Level 1: read-only monitoring and alerts

Import temperatures, status, demand and any native kWh entities. Create a notification if the house is cooler than expected while the heat pump reports an alarm, or if the interface has been unavailable for an extended period. Add separate safeguards against false alerts during planned defrost, hot-water priority and internet outages. This is often the best first deployment and introduces no competing setpoint controller.

Level 2: slow, vendor-approved supervisory scheduling

With approved controls, Home Assistant can request a holiday mode, adjust a modest heating-curve offset or shift a permitted domestic-hot-water schedule to coincide with an off-peak tariff or solar surplus. Respect the heat pump’s minimum on/off constraints, design temperatures, legionella-protection strategy and backup heating controls. A useful automation chooses a broad window; it does not hunt minute-by-minute for the lowest theoretical price at the expense of comfort and compressor life.

Level 3: externally directed setpoints

Only consider dynamic control after evaluating whether it improves the system compared with the manufacturer’s native weather compensation and thermal-store logic. Make the installer approve supported writable variables, allowable ranges and fallback behaviour. Manual overrides, anti-frost protection and high-temperature safety interlocks must continue to work without Home Assistant. Never send undocumented register writes to defrost, pumps, flow switches, safeties or refrigerant equipment.

Automated task	Good default	Why
Monitor energy consumption	Local energy meter AliExpress price + native read-only telemetry	Keeps the accounting boundary explicit
React to expensive electricity	Prefer manufacturer-supported broad schedule or curve offset	Avoids cycling and conflicts with weather compensation
Use midday solar surplus	Shift eligible DHW/heating demand conservatively	Do not exceed thermal safety or comfort limits
Handle HA/internet outage	Heat pump continues autonomously	Preserves heating and frost protection
Control compressor/defrost/safety sequence	Leave to manufacturer controller	External automation is not a certified control system

Installer checklist: 15 questions to get answered before signing

What are the exact outdoor, indoor/hydrobox and controller model numbers, including generation?
Has a full room-by-room design heat-loss calculation been completed for local design temperature?
What design flow temperature is required, and can existing radiators or underfloor heating deliver the necessary output?
Is the specified unit suitable for the building’s heat load, domestic-hot-water requirement, sound constraints and local servicing?
Which official network/interface adaptor is supplied: built-in LAN, Modbus option, ISG, MELCloud communications module or another part?
Where is the vendor documentation proving support for this controller firmware and specific gateway?
Is the interface local or cloud? Does it still provide values when the WAN connection is disconnected?
Can the installer demonstrate three must-have functions in Home Assistant—such as flow temperature, current electrical input and DHW temperature?
Which entities are read-only and which support documented, warranty-compatible adjustments?
Are subscriptions, developer accounts, API quotas, additional licences or gateway software options needed?
Who will maintain and support the gateway if the heat-pump firmware or Home Assistant version changes?
Can a certified electrical submeter cover the heat pump and its required auxiliaries for independent energy accounting?
What is the confirmed total installed cost of all integration components and commissioning, rather than only the heat pump hardware?
Will the manufacturer controller maintain frost protection, DHW hygiene and normal operation if Home Assistant, the LAN or broadband fails?
Will local service engineers support the system without demanding removal of unauthorised third-party electronics?

Bring this list to the HVAC contractor before placing the order. A salesperson may know the mobile app but not the supported API or register map. A technically detailed written answer is more valuable than “it should work with smart homes”.

Realistic total-cost comparison: built-in local API versus added gateway

Comparing integration expense requires care. A gateway sold at £X or €X may still need a separate licence and electrician or heating-engineer time. A subscription can look small annually but accumulate over the expected service period. The figures below are deliberately hypothetical purchasing scenarios, not retail quotes for NIBE, STIEBEL ELTRON or any other manufacturer.

Example integration scenario	Hypothetical one-off cost	Hypothetical recurring cost	Eight-year arithmetic
Built-in local interface already included	£0 extra	£0/year	£0 extra integration-specific spend
Optional approved gateway and commissioning	£350	£0/year	£350
Cloud plan for desired extra controls	£0 extra	£60/year	£480
Gateway + optional ongoing analytics service	£350	£60/year	£830
Separate circuit electricity monitor, installed	£250	£0/year	£250

Different heat pumps may have completely different total purchase and operating costs; a “free” API on an expensive or inappropriate unit is no saving. In the final comparison, price the whole installed heating system plus accessories, service contract and measured expected energy demand. Consult whole-home monitoring without cloud for a broader data-reliability framework.

Practical Home Assistant setup workflow

Commission the heat pump first. Establish normal heating, hot water and manufacturer settings without Home Assistant involvement.
Document hardware. Record unit model, controller firmware, gateway/communication module, LAN address and optional licences. Do not share credentials or register maps containing private information in public support requests.
Choose the exact documented integration. In Home Assistant, open Settings → Devices & services → Add integration, and select Nibe Heat Pump, STIEBEL ELTRON, MELCloud, MELCloud Home, myUplink, Viessmann ViCare or the supported product-specific option as appropriate.
Start read-only. Confirm outside, flow and DHW temperatures against the manufacturer controller. Note whether cloud updates lag the local display.
Identify cumulative kWh correctly. If available, test energy sensor units, monotonic behaviour, reset handling and timestamp resolution before adding to dashboards.
Perform an outage test. If acceptable to the installer and occupant, disconnect Home Assistant from its network, not the heat pump from power; verify manufacturer-controlled heat and hot water continue normally.
Add one approved automation at a time. Use a documented writable setpoint or schedule with manual override, limited frequency, range checks and a predictable offline policy.
Monitor over weeks. Compare telemetry with the heat-pump display and independent electricity readings, and review whether any automation actually improves comfort or cost.

Do not open covers, alter control wiring, connect RS-485 to unknown terminals or write experimental Modbus registers as part of this software setup. Those are installation and commissioning activities for suitably qualified professionals following the manufacturer’s instructions.

Common integration failures and how to diagnose them

Symptom	Likely category	Low-risk diagnostic step
Heat pump appears online in vendor app, not HA	Integration/account or wrong platform	Confirm MELCloud versus MELCloud Home or exact vendor platform and model
Modbus connection refused	Local network, access restrictions or disabled feature	Have installer confirm address, firmware, read-only setting and allowed client
Modbus entities show impossible negative/huge temperatures	Incorrect register, scaling, signedness or byte order	Compare register definition and raw reading with manufacturer map; avoid writes
Cloud entities become unavailable	Internet outage, token expiry, rate limit or service incident	Check service and integration logs; let native controller continue
Heat pump heats, kWh sensor reads zero	Unsupported sensor or energy boundary	Cross-check dedicated meter, measurement units and energy entity availability
HA reports COP but utility bill is higher	Omitted auxiliaries or incompatible averaging windows	Align electrical and thermal measurements on the same time boundary
Heating oscillates after automation	Competing setpoint schedules, tight thresholds	Disable supervisory writes and ask installer to check native control
Only a few settings available	Device/API or subscription restrictions	Review official entity list and API plan before spending on accessories

Buying recommendations by homeowner priority

Your priority	Shortlist approach	What should decide the final purchase
Offline local telemetry	Compatible NIBE S-series Modbus TCP; exact STIEBEL ELTRON/ISG combinations; Qube if locally available	Confirmed supported controller, documented registers, installer and service coverage
Simple mainstream cloud integration	Mitsubishi Electric MELCloud-supported system; relevant myUplink or ViCare product	Actual exposed entities, account rules and cloud resilience
Deep energy analytics	A correctly sized heat pump with dedicated electric and thermal metering	Reliable meter boundaries, accuracy, installation and long-term history
PV/DHW load shifting	System with documented slow supervisory DHW/schedule control	Native heating algorithm, thermal storage and fail-safe operation
Lowest project risk	Installer-supported system with independent electricity monitor and basic integration	Design heat loss, commissioning quality and straightforward service

Our preferred strategy: select heat-pump capacity and hydraulics with a competent local installer, then insist on an integration path that is documented for the quoted hardware. If the household needs genuinely local monitoring, a confirmed local Modbus system is usually the clearest route. If you mainly want temperatures, warnings and occasional holiday settings, a cloud integration may be adequate. Neither route makes an undersized emitter system or badly commissioned heat pump efficient.

Frequently asked questions

Which heat pump works best with Home Assistant without cloud?

Among the well-documented routes, compatible NIBE S-series models with built-in Modbus TCP are a strong starting point. Specific STIEBEL ELTRON units through supported ISG configurations, and Qube heat pumps through their dedicated Modbus integration, are further possibilities. Verify the complete model and interface, not just the brand.

Does every NIBE heat pump have Modbus TCP?

No. The documented built-in interface applies to relevant S-series equipment with supported firmware and configuration. Older models and other controller types may require gateways or different connection methods.

Can Mitsubishi Ecodan connect to Home Assistant?

Many MELCloud-enabled air-to-water systems are covered by the Home Assistant MELCloud integration. Another integration exists for MELCloud Home. Both are cloud-service routes; confirm which specific controller and account platform the installation uses.

Is MELCloud a local API?

No. Home Assistant’s MELCloud and MELCloud Home integrations depend on the relevant manufacturer cloud services. Losing internet connectivity does not necessarily stop the heat pump heating, but it does affect cloud-based Home Assistant access.

Can Home Assistant adjust a heat pump heating curve?

Sometimes. Specific devices, register maps or cloud API plans expose a permitted curve shift or slope control. Do not assume this is available from every integration or send undocumented writes. Keep manufacturer weather compensation and safety limits authoritative.

Is Modbus better than MQTT for a heat pump?

Neither protocol is intrinsically a better heating system. A manufacturer-supported Modbus register interface has a useful documented contract. MQTT can be excellent for presenting data, but an MQTT bridge may depend on unofficial equipment or reverse-engineered buses. The supported hardware path matters more than the transport name.

Can I add an ESP32 to any heat pump?

An ESP32 AliExpress price can collect data from approved exposed interfaces or a separate energy sensor, but it is not automatically safe or compatible to connect one to proprietary heating control buses. Never assume a serial connector is an open RS-485 or UART data service.

Will the Home Assistant Energy dashboard calculate heat-pump COP?

It can display electrical consumption when supplied a correctly configured cumulative energy sensor, but electrical consumption alone does not measure delivered thermal energy. A meaningful measured COP requires both energy quantities over the same interval and boundary.

What happens if the router or Home Assistant crashes?

The heat pump should remain under its certified manufacturer controller and continue essential heating, hot-water and protection functions. Any automation that must work to prevent freezing is incorrectly designed. Test and document offline behaviour before enabling supervisory controls.

Are cloud API subscriptions necessary?

Not always. Some ecosystems expose basic readings for free and require a subscription for advanced control, while others have API call quotas or feature restrictions. Check the relevant integration documentation and current vendor plan terms for the exact equipment.

Can I compare heat-pump efficiency between brands using their app readings?

Not reliably without verifying measurement methods. One product may estimate delivered heat, another may meter only the compressor, and a third may include auxiliaries. Use the same electrical and thermal boundaries for fair comparisons.

What is the most important purchase question?

Ask for written confirmation that the exact quoted controller, firmware, gateway and heat-pump model expose the three or four Home Assistant functions you need. Then ensure the engineering design and service plan make sense independently of any smart-home integration.

Official documentation and further reading

Technical product compatibility and documentation checked 16 October 2026. Integration features, firmware, API plans and availability may change. Sources below distinguish official Home Assistant and manufacturer documentation from community projects.

Safety, warranty and scope: This is a research and purchasing guide, not a heating-system design, wiring plan or instruction to override certified controls. Refrigerant, mains electricity, heat-pump bus wiring and safety configuration must be handled by competent, appropriately qualified installers under the manufacturer’s instructions and applicable national requirements. Do not defeat freeze protection, safety cut-outs, DHW hygiene controls, compressor interlocks or documented operating limits. No integration listed here is endorsed as suitable for every model from its manufacturer; check exact compatibility and local service support before purchase.