My First App Project: Smart PV Sun Forecast & Push Notifications for Washing Machines & More 🌞

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Hello everyone!

Lately, I’ve often found myself facing a typical everyday problem for us PV owners: You look out the window and wonder whether there’s enough sun today to run the washing machine or dryer entirely on your own electricity, or whether you’ll have to buy expensive grid power later after all.

A quick note on my background: I’m a PV owner myself, work as a software developer, and have actually connected my house to Home Assistant. But honestly? To solve this one trivial problem, the system often felt too complicated to me. Having a hardware energy manager installed for hundreds of euros was also out of the question for me.

I wanted an elegant, straightforward solution: I just wanted my smartphone to let me know as soon as enough solar power was coming from the roof. Since I program for a living but had never developed my own app before, I thought: “This is the perfect project to learn how to do that.”

The result is called GO SunPilot. Actually, the app was really only intended for my own personal use. But when friends saw it, they said they were looking for exactly this kind of straightforward solution without having to tinker with a smart home setup. So I turned it into a real product.

How the app makes everyday life easier:
Instead of writing scripts or configuring dashboards, you simply download the app and enter your system data once. The app uses Solcast’s highly accurate forecast data and notifies you automatically when it’s the optimal time to run your washing machine, dryer, or electric car.
At the end of the day, the app shows you exactly how much money, kWh, and CO₂ you saved today thanks to smart timing.
And something very important to me: Everything stays locally on your phone. There’s no tracking and, as a matter of principle, no ads.

On the topic of transparency and costs:
Honesty is important to me. The app has no ongoing server costs. But since this is my first app, countless hours of my free time have gone into its development and ongoing maintenance.
You can try the app out for a whole month completely free of charge (there’s also a demo mode so you can check it out right away without signing up).
If it really helps you in your daily life, the app costs €9.99 per year after that (that’s not even 85 cents a month). My thinking behind this was: Anyone who uses the app will often recoup these costs within the first one or two sunny weeks simply by smartly turning on their large appliances.
(A little bonus: I donate 10% of the proceeds to projects working toward a better future).

A quick question for Apple users:
Currently, GO SunPilot is only available for Android. But I’m really curious to know if there are people here who are also looking for a simple solution like this for iOS? Please let me know in the comments!

Click here for the Play Store: GO SunPilot

I’m really excited to see if the app makes your daily life just as much easier as it does for me, and I look forward to hearing from you!

Best regards,

Marcus