Heat pumps and solar – which ones a home energy manager can actually control
A heat pump is the biggest electrical load in most houses, which makes it the biggest opportunity. Whether you can move that load into the sunny hours or the cheap hours depends on one thing the brochures rarely mention: whether anything outside the manufacturer's own app is allowed to change a setpoint.
Supported brands What to look forThree ways to steer a heat pump
Zerofy runs in the cloud, so there is no energy manager box on your wall. It reaches the heat pump in one of three ways, and they differ a lot in how much control you get.
The manufacturer's cloud
The heat pump is already online through myUplink, Onecta, myVAILLANT or ViCare – or, for an air-to-air unit, through a Sensibo. You log in with that account and Zerofy reads the machine and moves setpoints – hot water, flow temperature, sometimes the room target. This is the version with real feedback: you see what the heat pump did with the instruction.
Daikin, NIBE, Alpha Innotec, CTC, CTA, Vaillant, Viessmann, PHNIX, Sensibo
Show these brandsSG Ready or a thermostat
Almost every heat pump sold in Germany and Austria since 2012 has an SG Ready input. No hub is needed for it – a Shelly switch or relay on those two terminals lets Zerofy tell any brand to hold off or run hard. tado° covers the other case, where you can only reach the rooms rather than the heat generator.
SG Ready (nearly every brand), tado°
Show the bridgesAnnounced
Integrations we have committed to but that are not live yet. If you are buying now and your brand is in this group, an SG Ready relay is the safe bridge in the meantime.
Bosch, Buderus
Show what is comingWhat SG Ready actually is
SG Ready ("Smart Grid Ready") is a German industry label, not a protocol. It means the heat pump has two digital inputs, and the four combinations of those inputs map to four states: blocked, normal, recommended on, and forced on. Manufacturers implement the last two differently – usually as a few degrees of extra offset on the heating curve and the hot water target.
It is crude compared to a cloud API, because nothing comes back: the heat pump does not report whether it acted. But it is universal, it needs no internet on the heat pump's side, and it works on machines whose manufacturer has no intention of opening anything.
Setting it up
- Have an electrician wire a Shelly switch or relay to the SG Ready terminals on the heat pump. There is no hub or gateway in between.
- Enable SG Ready in the heat pump's installer menu, and check what state 3 and state 4 actually do on your model.
- Add the relay in Zerofy and point Autopilot at it. Surplus solar or a cheap hour then flips the heat pump into its boost state.
State 4 ("forced on") runs the compressor hard and is meant for short periods. Most installers set up state 3 only. Check your manual before you let an automation use state 4 regularly.
What to look for if you want solar heating
Efficiency and noise matter whatever you do with the machine. These are the points that specifically decide whether a heat pump can work with your solar system and your tariff.
An interface you are allowed to use
A cloud API with a documented third-party path, or at minimum an SG Ready input. Ask the question before you sign – retrofitting a communication module is expensive and sometimes impossible.
Tip: Ask the installer directly: can a third-party energy manager read this machine and change the hot water setpoint?
A hot water tank worth filling
Storing surplus solar as hot water is the easiest win in the house. A 180–300 litre tank heated from 45 °C to 60 °C absorbs roughly 3–6 kWh, every sunny day, with no battery and no extra hardware.
Tip: An integrated tank saves space; a separate one is usually bigger and easier to control.
Inverter-driven, not on/off
A modulating compressor can run at 30 % and follow a 1.5 kW surplus. A fixed-speed machine can only switch on at full power, which means it either over-draws from the grid or does not start at all.
Tip: Almost everything current modulates. Check the minimum output, not just the maximum.
R290 (propane) refrigerant
Propane reaches 70–75 °C flow temperature without a backup heater, which makes it the practical choice for an older house with radiators. It also sidesteps the F-gas phase-down, so the machine stays serviceable.
Tip: R290 units have a safety distance to windows and doors – worth checking against your plot before you order.
SCOP, measured the way you will use it
A SCOP quoted at 35 °C flow temperature says little about a house that needs 55 °C. The same machine can show 5.0 and 3.2 on the same data sheet depending on the line you read.
Tip: Compare at the flow temperature your radiators actually need, in your climate zone.
Sound power, at the right distance
Air-to-water units sit outside and neighbours notice. Legally binding limits apply at the property boundary at night, and manufacturers quote sound power (L_WA), not what you hear at the fence.
Tip: Ask for the night-mode figure and have the installer check the distance to the boundary.
Brands Zerofy supports
What the app can actually do, per brand. A blank in a column means the brand's interface does not offer it, not that it is broken.
Daikin
Native integration
The most complete integration we have. Through the Daikin Onecta cloud, Zerofy reads the heat pump and can move the room setpoint, the flow temperature and the hot water setpoint, which is what Autopilot needs to park surplus solar in the building and the tank.
Zerofy can set
Room temperature Flow temperature Hot water setpoint
Autopilot
Solar surplus Dynamic tariff
NIBE
Native integration
Connects through myUplink. Zerofy reads the full state of the machine and triggers a hot water boost when there is surplus solar or a cheap hour, which on a NIBE is the most effective lever: the tank is the cheapest battery in most houses.
Zerofy can set
Hot water boost
Autopilot
Solar surplus Dynamic tariff
Alpha Innotec
Native integration
One of the three ait-group brands Zerofy supports. Monitoring is complete and Autopilot can call for a hot water boost; the heating curve itself stays with the controller on the wall, which is usually where you want it.
Zerofy can set
Hot water boost
Autopilot
Solar surplus Dynamic tariff
CTC
Native integration
The Swedish ground source specialist. Same shape of integration as NIBE and Alpha Innotec: full monitoring plus a hot water boost that Autopilot can call when your own electricity is cheap or free.
Zerofy can set
Hot water boost
Autopilot
Solar surplus Dynamic tariff
CTA
Native integration
The Swiss manufacturer behind the Optiheat range, and a common sight in Swiss new builds. Monitoring and a hot water boost, driven by your own production and by the tariff.
Zerofy can set
Hot water boost
Autopilot
Solar surplus Dynamic tariff
Vaillant
Beta
In beta. Through the myVAILLANT cloud Zerofy reads the system and can move the room and flow setpoints as well as boost hot water – close to the Daikin level of control. You need a Vaillant online account and the sensoNET or built-in connectivity module.
Zerofy can set
Room temperature Flow temperature Hot water boost
Autopilot
Solar surplus Dynamic tariff
Viessmann
Beta
In beta, via the ViCare cloud. Zerofy can raise the flow temperature and the hot water setpoint and trigger a one-off boost, which covers both of the useful places to store surplus heat. Requires a Vitoconnect or a Vitocal with built-in connectivity.
Zerofy can set
Flow temperature Hot water setpoint Hot water boost
Autopilot
Solar surplus Dynamic tariff
PHNIX
Native integration
Monitoring and setpoint control work, but Autopilot does not drive PHNIX units yet – you can see and set, not automate. Worth knowing before you buy if automation is the reason you are reading this page.
Zerofy can set
Room temperature Flow temperature
Autopilot
–
Sensibo
Native integration
For air conditioners and air-to-air heat pumps – the split units that are the normal way to heat a home in Southern Europe and increasingly common everywhere. Sensibo sits in front of the infrared remote, and Autopilot can run the unit on surplus solar or on price.
Zerofy can set
On/off Room temperature
Autopilot
Solar surplus Dynamic tariff
SG Ready
Via a bridge
Nearly every heat pump sold in Germany and Austria since 2012 has an SG Ready input: two terminals that tell the machine to hold off or to run hard. There is no hub involved – a Shelly switch or relay on those terminals is all it takes, and Zerofy switches it like any other Shelly. That makes almost any brand controllable, without reading anything back from the machine.
Zerofy can set
On/off
Autopilot
Solar surplus Dynamic tariff
tado°
Via a bridge
Room thermostats and radiator valves rather than a heat pump interface. Zerofy can see and set room temperatures, which is useful in a flat or where the heat generator itself is closed, but Autopilot does not steer tado° yet.
Zerofy can set
Room temperature
Autopilot
–
Bosch
Coming soon
Announced. Bosch and Buderus share the HomeCom/EMS platform, so the two will arrive together.
No brand matches that filter.
Heat pump model database
Specifications for the models in our database, for comparison of efficiency, output and noise. Figures are from the manufacturers' data sheets. We deliberately do not quote a purchase price – for a heat pump the installed cost depends far more on your house, your radiators and your installer than on the machine.
| Model | Type | Max output | SCOP (B0/W35) | Noise | Integrated tank | Remote monitoring |
|---|---|---|---|---|---|---|
| Alpha-Innotec Alterra WZS 122 V-Line | Ground source | 12.2 kW | 5.4 | 44 dB | 180 l | Yes |
| Alpha-Innotec LWD 92 V-Line | Air to water | 8.2 kW | 4.06 | 54 dB | 180 l | Yes |
| Bosch COMPRESS 7000 iAW9 + AWN 9 | Air to water | 9 kW | 4.9 | 47 dB | 185 l | Yes |
| Bosch CS7001i LWM 12 | Ground source | 12 kW | 5.85 | 41 dB | 180 l | Yes |
| Buderus Logatherm WSW186i-12 | Ground source | 12 kW | 5.55 | 41 dB | 180 l | Yes |
| Daikin Altherma 3 H MT 8 kW + BUH9 IG | Air to water | 8 kW | 4.69 | 53 dB | 180 l | Yes |
| Daikin EGSAX10D9WG | Ground source | 9.55 kW | 5.2 | 41 dB | 180 l | Yes |
| Mitsubishi PUD-SWM100YAA + EHST20D | Air to water | 9 kW | 4.5 | 59 dB | 200 l | Yes |
| NIBE F1245 | Ground source | 12 kW | 4.9 | 43 dB | 180 l | Yes |
| NIBE F2120-8 | Air to water | 8 kW | 4.1 | 53 dB | – | Yes |
| Panasonic KIT-AXC9HE8 T-CAP | Air to water | 9 kW | 4.6 | 51 dB | 185 l | Yes |
| Samsung SET-AE080BXYDEG-1 | Air to water | 8 kW | 4.64 | 42 dB | 194 l | Yes |
| Thermia Atlas 12 | Ground source | 12 kW | 5.86 | 43 dB | 184 l | Yes |
| Vaillant flexoCOMPACT exclusive VWF 118/4 | Ground source | 11.18 kW | 5.2 | 43 dB | 171 l | Yes |
| Viesmann Vitocal 252-A 9,7 kW, AWOT-E-AC 251.A10 | Air to water | 9 kW | 3.91 | 54 dB | 190 l | Yes |
| Viessmann Vitocal 333-G | Ground source | 10.3 kW | 5.4 | 46 dB | 220 l | Yes |
No model matches that search.
Heat the house when the electricity is yours
A heat pump that runs at noon on your own solar costs a fraction of the same kilowatt hours bought at six in the evening. Zerofy connects the solar system, the tariff and the heat pump, and decides for you.
- Solar surplus goes into the hot water tank and the building instead of the grid
- On a dynamic tariff, heating moves into the cheapest hours of the day
- Consumption, production and cost sit in one history next to your car and your plugs
- Works with the manufacturer's cloud where it exists, and with SG Ready where it does not
Questions we get asked
Will a heat pump run my electricity bill up?
It replaces fuel with electricity, so the electricity bill goes up and the gas or oil bill goes away. Whether the total falls depends on your SCOP and on the gas-to-electricity price ratio where you live. Running the machine on your own solar and in cheap tariff hours is what turns a reasonable result into a good one.
Does running on solar surplus damage the heat pump?
No, as long as you move setpoints rather than switch the compressor. Raising the hot water target or the flow temperature for a few hours is exactly what the controller is designed for. Cycling a compressor on and off repeatedly is what shortens its life – which is one reason we prefer a cloud API or SG Ready state 3 over a relay in the supply.
How much can I actually shift?
Realistically, the hot water tank plus a degree or two of building temperature. A 250 litre tank is worth roughly 5 kWh; the building fabric of a well-insulated house is worth more but you feel it. Together that is often enough to absorb an entire sunny afternoon's surplus in spring and autumn.
My heat pump is not in the list. Is it useless?
Almost certainly not. If it was installed in Germany or Austria in the last decade, it has an SG Ready input, and a relay on those terminals gets you most of the benefit. You lose the readback – Zerofy will not know the current flow temperature – but the control still works.
Do I need a battery as well?
Not for this. A hot water tank stores heat at a fraction of the cost per kilowatt hour of a lithium battery, and a heat pump turns 1 kWh of electricity into 3–4 kWh of heat on the way in. If your goal is to use your own solar rather than to run the house at night, the tank is the better first purchase.
Air to water or ground source?
Ground source is more efficient and quieter, and costs considerably more to install because of the borehole or the collector. Air to water has closed much of the efficiency gap, especially with R290, and is what most retrofits use. Both work the same way with an energy manager.
Brand capabilities reflect the Zerofy app in October 2026 and change as integrations ship – the setup guides in our documentation are always current. Model specifications come from manufacturers' data sheets and are provided for comparison, not as a quotation.