Note
We support most heat pumps with a Smartgrid Ready contact.
What is SG-Ready?
SG-Ready (Smart Grid Ready) is a standardized interface defined by the German Heat Pump Association (BWP). It lets an energy management system control a heat pump using just two physical relay contacts, no digital communication required.
Each relay is either open (off = 0) or closed (on = 1). The combination of both relays encodes one of four operating modes. The binary code in the table below directly represents the relay states: the first digit is Relay 1, the second digit is Relay 2.
For example, 10 means Relay 1 is closed and Relay 2 is open.
This relay mapping is standardized, every SG-Ready certified heat pump uses the same relay ordering. The exact behavior (e.g. how aggressively the pump boosts) depends on the manufacturer.
The Four SG-Ready Modes
| Binary Code | Relay 1 | Relay 2 | Mode |
|---|---|---|---|
| 00 | Open | Open | Normal operation: heat pump runs on its own schedule |
| 01 | Open | Closed | Recommended operation: heat pump is encouraged to run more (e.g. solar surplus) |
| 10 | Closed | Open | Block: heat pump is switched off to reduce grid load |
| 11 | Closed | Closed | Boost: heat pump runs at maximum power |
How Sunlight Group Uses SG-Ready
Sunlight Group uses three of the four modes. Mode 01 (Recommended) is part of the standard but is not currently used.
| Binary Code | Relay 1 | Relay 2 | Sunlight Group Purpose | Typical Heat Pump Response |
|---|---|---|---|---|
| 00 | Open | Open | Default: device operates autonomously | Runs according to its own internal schedule |
| 10 | Closed | Open | Grid stabilization: reduce consumption | Switches off immediately; resumes when signal changes |
| 11 | Closed | Closed | Boost: maximize self-consumption or support the grid | Runs at maximum power regardless of internal state |
Practical Example: Daikin Altherma
On a Daikin Altherma, Relay 1 connects to terminal S10S (pins 9–10) and Relay 2 connects to terminal S11S (pins 5–6).
| Situation | Relay 1 | Relay 2 | Code | Effect |
|---|---|---|---|---|
| High electricity price or grid overload | Closed | Open | 10 | Heat pump switches off |
| Excess solar energy or cheap grid electricity | Closed | Closed | 11 | Heat pump runs at full output |
| No active signal | Open | Open | 00 | Heat pump manages itself |
See the Daikin Altherma installation guide for full wiring instructions.