Questions and answers about GridZeno: What people ask about.

GridZeno is a dongle for solar inverters and a service that charges the battery when power is cheap and uses it when power is expensive. The dongle sits in your inverter, and the service shows you your system and makes a plan for every quarter hour. See how it fits together.

Yes. You order the dongle here on the site and only pay for the dongle and the shipping. The subscription only starts on the day the dongle is connected to your system. Order the dongle.

No. Without a battery you get a full overview of production, consumption and prices. But the two biggest gains, shifting consumption in time and avoiding expensive import, need a battery to work with. Read whether a battery pays off.

Yes. The dongle controls locally and follows the plan it has already fetched. If the connection is gone for more than 45 minutes, it does what you have chosen under Automatic: it follows the plan for as long as it lasts, or lets the inverter run on its own settings. The plan reaches at least a day ahead, and your battery limits are in the inverter's own settings, so they hold in both cases. You lose the overview in the app until the connection is back, but Home Assistant on your network still gets the measurements directly from the dongle.

Light gives an overview. Smart adds simple automatic control. Pro adds forecast-based charging, selling from the battery at high prices, your own rules and the detailed report. See the full comparison.

In October 2026 power on our own system cost DKK 391 with GridZeno against DKK 511 with the inverter on its own, so DKK 120 saved in a month. What your system saves depends on your system, your consumption, your electricity contract and how much prices vary. We show you the actual value afterwards. See where the gain can come from, and see measured figures from two real systems.

The dongle costs DKK 549 once plus shipping: DKK 49 to a parcel shop or DKK 79 to the door. After that DKK 0 for Light, DKK 39 a month for Smart or DKK 79 for Pro. The subscription only starts when the dongle is connected. All prices include VAT.

Pro costs DKK 948 a year. Your gain has to exceed that threshold before it makes sense. If you can't see it holding up for your system, choose Smart or Light. The calculator on the savings page says so itself when the numbers are too thin.

Yes, once you have chosen your grid company and electricity agreement. Then we add the grid tariff, Energinet's tariffs, electricity tax, your electricity supplier's surcharge and VAT on top of the spot price. Your electricity supplier's fixed subscription is deliberately not included, because it doesn't follow your consumption. We work out the selling price from the buyer of surplus power you choose. See what the price is made up of, and the grid tariffs for 2026.

The selling price: the spot price minus small deductions for Energinet and your grid company and your buyer's trading fee. From 25 July to 2 October 2026, a kWh sold gave about DKK 0.36 in the middle of the day in DK1, while the same kWh cost about DKK 2.30 to buy from 17:00 to 21:00. That is why a kWh you use yourself is almost always worth more than one you sell. See the calculation.

The ones listed as supported on the compatibility page. An inverter is only listed as supported once it has run on a real system, and each model has its own page, e.g. Growatt WIT. If yours isn't there, or you're unsure, write to us with the model and firmware, and we'll assess it before you buy.

Not for the dongle itself. It plugs into the inverter's communication port, not into 230 V. If anything has to be done to the fixed electrical installation, it must be carried out by an authorised electrician.

15-30 minutes to mount and connect, depending on the model, and five to ten minutes to set up. Some inverters have to be opened by an electrician, and the guide for your model. The measurements come in straight away. The dongle can't fetch measurements from before it was plugged in, so the graphs start on that day. See the whole journey.

Only if you say yes. The first time, Welcome asks whether GridZeno should control your system straight away or show you the plans first. You can switch to Manual at any time under Automatic. The whole plan is still calculated and shown, but the dongle doesn't control the inverter.

Yes. GridZeno has its own integration for Home Assistant, which you install from HACS. It finds the dongle on your network and talks directly to it, bypassing the cloud. On all subscriptions you get the measurements, the energy meters for the energy dashboard and the plan, and you can control the system from Home Assistant when you control it yourself. Your prices and the solar forecast require Smart or Pro. See the Home Assistant guide.

Yes. Set the control to Manual. Then an ongoing grid charge or hold stops, and the dongle puts the inverter's own settings back, including the charge limits it had before GridZeno changed them. After that, it changes nothing on the inverter. If you want to remove the dongle, set the control to Manual first, so the inverter isn't left in the middle of a charge.

Measurements from your system (production, consumption, battery, buying and selling) as well as what you write in the setup yourself. Detailed measurements are kept for six hours, quarter-hour data for two years. See the full description.

Only if you turn it on yourself. If you turn it off again, the data already copied is deleted, not just stopped.

No, never. The dongle creates its own secret and registers itself. You link it to your account from the app or the browser, where you're already logged in.

Only one necessary cookie, which remembers your choice about cookies. We only use visitor statistics if you say yes, and they set no cookies. You can change your choice under Cookie settings at the bottom of the page. See everything the website uses.

You can delete your account yourself in the app under Settings or in the web app under Profile. Then the account and all system data are deleted, including in the forecast service, and you get a confirmation by mail. We do, however, keep orders and invoices for 5 years, as the Danish Bookkeeping Act (bogføringsloven) requires. If you only want to opt out of model training, you turn it off under Settings. See how, and what we keep.

Only the dongle. A power supply and cables aren't included, because most people already have them lying around, and we don't want to send out anything that ends up as waste. If you're missing something, you can add a USB power kit (DKK 79), a LAN cable Cat6, 1.5 m (DKK 39) and a Modbus cable Cat5e SF/UTP, 1.5 m (DKK 39) to the same order at no extra shipping cost.

DKK 49 per order to a a parcel shop or parcel locker, which you choose yourself, or DKK 79 for delivery to the door, however many dongles there are in the order. If you choose delivery to the door, PostNord leaves the parcel at the door if you aren't at home. Once PostNord has left the parcel at the door, it has been delivered, and after that it's your responsibility if it goes missing or is damaged. Typically 2-7 working days.

1 month from the start of the subscription, which is the day the dongle is connected to your system. After that, the subscription can be cancelled at any time with effect from the end of the month you have paid for, and you can always switch to Light, which is free. See how to cancel.

Yes. You have the statutory 14-day right of withdrawal, and on top of that 100 days' free right of return from the day you activate the dongle. You send the dongle back from your profile, and we pay the return shipping. Read the terms.

The change applies from the end of the month you've paid for. After that, GridZeno turns off the features the new subscription doesn't include, and if you go to Light, the control is set to Manual. If you switch up again, the difference for the rest of the month is charged straight away, and the new subscription applies as soon as the payment has gone through. Coming from Light, the control is set to Automatic. You can switch to Manual at any time under Automatic.

Kan-El, a Danish electrical company in Åbyhøj near Aarhus, CVR 32967574. Kan-El develops GridZeno and sells the dongle. Read why GridZeno exists.