SMA + SG Ready

What Zerofy can do with SMA 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, which a typical SMA home system (3–10 kW) can cover on sunny days.
• Zerofy gets new SMA data every 5 minutes. Heat pumps shouldn’t switch often, so set a minimum runtime in Autopilot.
• Zerofy also shows your SMA battery, so you can see whether surplus goes into the battery or into the heat pump.
• 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 SMA and SG Ready offer on their own

SMA: The Sunny Home Manager 2.0 runs heat pumps via EEBus (Vaillant, Wolf, NIBE S-series), SEMP (Stiebel Eltron, Tecalor, AEG) or an SG Ready input switched by a Shelly, Moxa or SMA relay. my-PV heating rods (AC ELWA, AC•Thor) are controlled via SEMP.

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.

Directly, without Zerofy: The Sunny Home Manager 2.0 switches the SG Ready input of any SG Ready heat pump through a supported relay, e.g. a Shelly 1/1PM, a Moxa ioLogik E1214 or an SMA switching device.

Zerofy is the alternative if you want SMA, SG Ready and your other devices in one app, with dynamic tariffs and forecast-based Smart mode.

Setting up SMA and SG Ready in Zerofy

1. Connect SMA

Zerofy connects to your SMA system through the SMA Sunny Portal cloud, using your Sunny Portal login.

1. Make sure your SMA inverter is cloud-capable and registered in Sunny Portal.
2. Add SMA in Zerofy and log in with your Sunny Portal credentials.

Step-by-step guide for SMA

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 SMA solar production.

Learn more about Smart Mode

About SMA and SG Ready

SMA – German inverter maker based in Niestetal near Kassel. Homes typically have a Sunny Boy (single-phase) or Sunny Tripower (three-phase) string inverter, or a Sunny Boy Smart Energy (3.6–6 kW) or Sunny Tripower Smart Energy hybrid inverter with the SMA Home Storage battery (3.28 kWh modules, up to 16.4 kWh). Monitoring app: SMA Sunny Portal / SMA Energy 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 SMA