Hoymiles + SG Ready

What Zerofy can do with Hoymiles and SG Ready

In practice

• When there’s enough surplus, Zerofy switches the relay and the heat pump receives the SG Ready signal. How it reacts – for example by heating the hot-water tank to a higher temperature – is set in the heat pump’s own controller.
• A heat pump draws roughly 1–3 kW while running. A Hoymiles balcony system covers only a small part of that, a rooftop system (Hoymiles systems range up to 10 kW) much more on sunny days.
• Zerofy gets new Hoymiles data only every 15 minutes, so the heat pump reacts to clouds with some delay. A slightly higher activation threshold and a minimum runtime in Autopilot keep it steady.
• Set in the heat pump controller how many degrees the hot-water and heating setpoints rise in the boost state (“recommended operation”); the default differs by manufacturer. Fronius and Enphase only switch between normal and recommended operation, so the heat pump keeps its own minimum run times.

What Hoymiles and SG Ready offer on their own

Hoymiles: On the three-phase HiOne all-in-one storage system (G3), Hoymiles has a dry contact (DO1) for SG Ready heat pumps, but the manual (January 2026) lists heat pump control as “coming soon”. Hoymiles microinverters have no heating control.

SG Ready: Several inverter energy managers drive SG Ready directly: Fronius (GEN24 or Datamanager 2.0 with Smart Meter and a 12 V relay), SMA Sunny Home Manager 2.0 (relay or I/O module), Huawei EMMA, SolarEdge Home Load Controller or Smart Energy Relay, Sungrow SH-RT hybrids (built-in DO relay) and the Enphase IQ Energy Router+. Most of them switch on a fixed surplus threshold.

Zerofy connects the two: it reads Hoymiles production and controls your SG Ready heat pump to match, together with your other devices in one app, with dynamic tariffs and forecast-based Smart mode.

Setting up Hoymiles and SG Ready in Zerofy

1. Connect Hoymiles

Zerofy connects to the Hoymiles S-Miles Cloud with your S-Miles account and reads your PV production.

1. If your installer hasn’t set up your plant yet, register it in the S-Miles Installer app (use DIY mode if you install it yourself).
2. In Zerofy, add an inverter, choose Hoymiles and log in with your S-Miles credentials.
3. Use Autopilot (Solar Mode) to switch devices on solar surplus.

Good to know: Zerofy reads PV production only from Hoymiles, not grid meter or battery data, and stores the power history in 15-minute steps (5 minutes for most other brands).

Step-by-step guide for Hoymiles

2. Connect SG Ready

Zerofy switches the SG Ready inputs through a smart relay such as a Shelly that you connect to Zerofy; Autopilot then sends SG Ready signals based on solar surplus and low electricity prices.

1. Have an electrician wire a smart relay (e.g. Shelly) to the heat pump’s SG Ready inputs.
2. Add the relay to Zerofy.
3. Configure the relay as SG Ready controller in the app and turn on Autopilot.

Good to know: SG Ready gives Zerofy on/off-style states, not temperature readings or setpoints. To use all four states, the relay needs two channels, one per SG Ready input.

Step-by-step guide for SG Ready

3. Turn on Autopilot

In Zerofy, open your SG Ready heat pump, turn on Autopilot and choose Solar – or Smart to also use dynamic tariffs and forecasts. Set the priority, activation threshold and minimum runtime.

Dynamic tariffs

Zerofy can also run your SG Ready heat pump on dynamic electricity prices (EPEX Spot or Nord Pool, e.g. Tibber or aWATTar) or on a fixed time-of-use tariff. Smart mode combines those prices with forecasts of your household consumption and your Hoymiles solar production.

Learn more about Smart Mode

About Hoymiles and SG Ready

Hoymiles – Hoymiles (Hangzhou, China) is one of the largest microinverter makers. In Europe it is best known for balcony systems such as the HMS-800W-2T (switchable 600/800 W) with the MS-A2 balcony battery, and it also sells HYS/HYT hybrid inverters with home batteries. Monitoring app: S-Miles Cloud (S-Miles app).

SG Ready – SG Ready (Smart Grid Ready) is a label introduced in 2012 by the German Heat Pump Association (BWP) for heat pumps that an external controller can switch between four operating states via two contacts. It is a signalling convention, not a data protocol: the heat pump’s own controller decides how far to raise temperatures in the boost state. Products: Heat pumps with the SG Ready label (two potential-free control inputs), from many manufacturers.

Manufacturer information last checked: October 2026.

All devices that work with Hoymiles