SolarEdge + CTA

What Zerofy can do with SolarEdge and CTA

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 SolarEdge home system (3–10 kW) can cover on sunny days.
• Zerofy gets new SolarEdge data every 5 minutes. Heat pumps shouldn’t switch often, so set a minimum runtime in Autopilot.
• Zerofy also shows your SolarEdge battery, so you can see whether surplus goes into the battery or into the heat pump.
• CTA’s own tip for SG Ready operation: if rooms get too warm or too cold, change the upper temperature limit by 1 °C at a time and leave it for one to two days before adjusting again; agree the values with your heating installer.

What SolarEdge and CTA offer on their own

SolarEdge: The SolarEdge Home Load Controller switches the SG Ready input of most air-to-water heat pumps on excess solar, with two configurable set points; it connects to the inverter via the SolarEdge Home Network and needs no ONE Controller. Vaillant heat pumps from 2018 with EEBUS can be controlled through the ONE Controller, and the SolarEdge Home Hot Water Controller feeds surplus into an immersion heater.

CTA: For PV self-consumption, CTA connects its heat pumps to external energy management systems via a PV input, SG Ready or Modbus (Optiheat and Aeroheat). CTA publishes SG Ready instructions per model and a compatibility list for the Swiss Solar Manager gateway (Modbus TCP/RTU).

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

Setting up SolarEdge and CTA in Zerofy

1. Connect SolarEdge

Zerofy connects to SolarEdge’s monitoring cloud with the same login you use for the SolarEdge Monitoring website or the mySolarEdge app.

1. Make sure your SolarEdge inverter is online and your account has the Owner role on the site.
2. Add a new SolarEdge device in Zerofy.
3. Log in with your SolarEdge Monitoring / mySolarEdge credentials and follow the on-screen prompts.

Good to know: Your account needs the Owner role, which the installer usually assigns to the system owner during setup; ask your installer if you don’t have it. Battery and meter data depend on how your system is configured.

Step-by-step guide for SolarEdge

2. Connect CTA

The Zerofy docs have no CTA-specific guide; the documented way to control a CTA heat pump is Zerofy’s SG Ready integration, with a smart relay such as a Shelly wired to the heat pump’s SG Ready inputs.

1. Check in CTA’s SG Ready compatibility list that your model and controller (Optiplus, Optiplus 3, Aeroplus 2.0/2.1) are listed.
2. Have an electrician wire a smart relay (e.g. Shelly) to the heat pump’s SG Ready inputs.
3. Add the relay to Zerofy and configure it as SG Ready controller.

Good to know: CTA marks Optiheat Inverta units and several Aeroheat models as needing a software or controller update for SG Ready. For older or unlisted units, CTA says integration can mean extra cost, e.g. a controller replacement.

Step-by-step guide for CTA

3. Turn on Autopilot

In Zerofy, open your CTA 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 CTA 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 SolarEdge solar production.

Learn more about Smart Mode

About SolarEdge and CTA

SolarEdge – Israeli company (Herzliya) known for inverters with a power optimizer on every module. Homes typically have a SolarEdge Home Wave single-phase or Home Hub three-phase inverter with optimizers, often with a SolarEdge Home Battery and SolarEdge Home smart-energy accessories. Monitoring app: SolarEdge Monitoring / mySolarEdge app.

CTA – CTA AG is a Swiss manufacturer of heat pumps and cooling machines, with production at its headquarters in Münsingen near Bern. Its home range covers Optiheat ground-source and water-source heat pumps and Aeroheat air-source heat pumps. Products: Optiheat (brine/water and water/water), Optiheat Inverta, Aeroheat (air/water, indoor and outdoor units), Aeroheat Inverta.

Manufacturer information last checked: October 2026.

All devices that work with SolarEdge