# Daikin Tanks, Madoka & Onecta — smart-home review (2026)

Independent expert review of the Daikin smart-home stack: EKHWSP buffer tanks, the three-colour Madoka thermostat and the Onecta gateway. Including the Apple Home workaround.

Canonical: https://www.warmtepompkopen.nl/en/tanks-controls-smart-home-review
Laatst bijgewerkt: 2026-09-25

Expert review · Cedric Day

The peripheral stack matters as much as the heat pump itself. We test the EKHWSP buffer tanks, the Madoka thermostat in three colours and the Onecta gateway — including the Apple Home workaround.

Most reviews stop at the heat pump. We push further: the tank, the thermostat, the app and the gateway shape the daily user experience far more than the SCOP number.

## 1. EKHWSP buffer tanks

Available in 150 L, 200 L and 300 L. Required for radiator-only systems or short underfloor circuits; optional for high-volume underfloor systems.

## 2. Madoka thermostat — three colours

Daikin is one of the few manufacturers offering the same thermostat in three finishes: gloss white, metallic silver and matte black. A small thing that matters in modern interiors.

## 3. Onecta — app + gateway

The Onecta cloud app handles schedules, holiday mode, push notifications and remote diagnostics. The WLAN cartridge ships standard with the Altherma 4 H. For PV integration or rate-limit-free local control you also need the HomeHub.

## 4. Verdict

4.2 / 5. Excellent core, three honest gaps (no native HomeKit, cloud rate limit, HomeHub costs extra). For Home Assistant users this is one of the best controllable heat-pump platforms on the market.

## FAQ

**Does Daikin Onecta work with Apple Home / HomeKit?**

No. The Daikin NL 2026 catalog lists no native Apple HomeKit integration for Onecta. The only stable workaround is a Home Assistant intermediate server with the HomeKit bridge. Budget for a Raspberry Pi (€80) plus the Daikin HomeHub (Modbus IP) for local control.

**Do I need a buffer tank with an Altherma 4 H?**

Not always. If your underfloor-heating loop holds more than 40 litres of water per kW of heat-pump capacity, the heat pump can modulate without a buffer. For radiators or short heating circuits Daikin advises an EKHWSP buffer of 150-300 L for anti-cycling, hydraulic decoupling and defrost-energy storage.

**Which Madoka colour suits me?**

Three SKUs: BRC1HHDW7 (RAL 9003 gloss white) is the most neutral and ships standard with every Altherma 4 H. BRC1HHDS7 (RAL 9006 metallic silver) suits modern interiors. BRC1HHDK7 (matte black) is the choice for smart-home enthusiasts.

**What is the difference between the Onecta WLAN cartridge and the separate adapter?**

The BRP069A78 cartridge sits standard in the MMI2 SD slot of the Altherma 4 H — free. The BRP069A71 is a separate module for systems with weak WiFi or for other Altherma series. If WiFi is poor: cartridge out, BRP069A71 wired in.

**Can I link my solar panels to the heat pump via Onecta?**

Direct via Onecta: no. You need the Daikin HomeHub (catalog ~p.190). It measures PV surplus via the Dutch P1 meter and steers it to the heat pump or buffer-tank booster — Daikin use-case 1. Indicative cost €450 for the HomeHub.

**Is Energy+ rate-limited?**

Yes. The Onecta cloud API enforces a rate limit of a few dozen requests per minute per account. For users polling every minute (PV modulation), a local Modbus IP/RTU connection via HomeHub is more stable and works without cloud dependency.

Read the Dutch original at [/tanks-bediening-smart-home-review](https://www.warmtepompkopen.nl/tanks-bediening-smart-home-review).

## Verder lezen

- https://www.warmtepompkopen.nl/tanks-bediening-smart-home-review