
OnSun: Rooftop Solar Forecast
Run Appliances on PV Energy
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Free
In-App Purchases
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About
OnSun predicts your rooftop solar seven days ahead and tells you the best time to use power. Use the app to look ahead and schedule the laundry, the dishwasher and the EV charger on energy you already made, instead of buying it back at night.
WHAT ONSUN DOES
• 7-day solar forecast: solar generation in kWh, showing how much your panels will produce, and when, through each day of the week ahead, customized for your system
• Predicts solar output and solar irradiance for your panels and your location
• A confidence range on every solar prediction, so you see best and worst case
• Tells you when to run appliances, then sends a solar reminder
• Solar savings per appliance - what you save, in dollars and in kWh
• Solar usage and solar self consumption shown over time
• Sunny days flagged a week out, with the peak hours worth planning around
• Rainfall overlaid on the sunshine, so you can pick the best time to dry the laundry if you don't use a dryer
SOLAR APPLIANCES YOU CAN SCHEDULE
• Washer and dryer
• Dishwasher
• Solar EV charging - an EV charging schedule built around the sunniest days
• Solar pool pump timing
• Air conditioning and space heater
• Oven and dehumidifier
WORKS WITH ANY INVERTER
It makes no difference whose inverter you have. OnSun never connects to your inverter. No hardware, no wiring, no login. Your location, panel size and the local weather are all it needs. Compare the forecast against what you actually get and adjust the performance setting to sharpen it.
An inverter app only shows what already happened, when the chance to do anything is gone. OnSun looks ahead instead - part calculator, part planner, part weather app.
WHY TIMING BEATS EXPORTING
Every kWh you use while the sun is up is a kWh you don't buy from the grid at the electricity prices your utility charges. Solar export earns a net metering credit worth a fraction of that, and even off-peak rates cost more than sunshine. Shift the load into daylight and you reduce your electricity bill.
SOLAR SCHEDULING, SET ONCE
Every appliance draws a different number of watts. A dishwasher runs in short bursts, an EV charger pulls for hours. OnSun matches each power profile against your PV forecast, works out when to run appliances, then sends the notification or alert when it is time.
HOW THE PV FORECAST WORKS
Professional weather data, modelled against the sunlight your panels actually capture. The same modelling used for large commercial rooftop PV systems, now in your pocket. There is no cheap electricity like the power you already own.
FREE vs PRO
Free: 3-day forecast, 2 appliances.
Pro: full 7-day forecast, unlimited appliances, more frequent forecast updates, and long-term home energy insights so you can watch the power bill and the energy bill come down.
You paid for the panels. Download OnSun free and put your home solar to work.
Terms of Use: https://onsun.app/terms-of-service.html
Review: "I'm terrible at remembering to make the most of my solar and end up giving it all away to the grid, but this sends me reminders and plans the next few days for me. The notifications are great, I actually get up and put the washer on! Even started meal prepping with the oven at peak solar time. Can see this saving me from wasting power real quick." - Andytar
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What's New in OnSun
2.0.4
October 21, 2026
This update is all about getting the forecast closer to your real system, and making your results easier to find. • Multiple solar arrays with their own tilt and direction, plus an optional inverter limit. • One Insights tab for the week ahead and your history. • Add an appliance straight from any day on Insights. • Fixes and performance improvements. Thanks for using OnSun. If it's helping, a rating in the store means a lot.
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Subscriptions & In-App Purchases
OnSun Pro (Yearly)
Plan your appliances around your solar, all year.
$24.991 Year
1 Year trial






