8 min read · By Dr Steven Percy
You spent thousands on solar panels expecting lower electricity bills. But the bills barely moved. Here's why it's happening to millions of households around the world, and what you can actually do about it.
Solar panels are one of the best investments a homeowner can make. The technology works, the savings are real, and the environmental benefits are undeniable. But there's a catch that most solar installers don't emphasise: the savings depend almost entirely on when you use electricity, not just how much your panels produce.
The average solar household exports somewhere between 50% and 70% of the energy their panels generate. That exported energy earns a feed-in tariff, typically between 5 and 10 cents per kilowatt-hour. Later that same day, they buy electricity back from the grid at full retail price: 25 to 45+ cents per kWh depending on where you live.
That price gap is where your savings disappear. You're essentially selling your solar energy at a discount, then buying it back at a premium.
Your solar panels produce the most energy between roughly 9am and 3pm. But think about what your household is doing during those hours. If you're at work and the kids are at school, nobody is running the washing machine, the dishwasher, or charging the car. The house might be drawing just 500 watts for the fridge and a few devices on standby, while your panels are generating 4,000 watts or more.
All that surplus energy flows straight back to the grid. Your meter spins backwards, sure, but you're credited at a fraction of what you'll pay when you start cooking dinner, running the dryer, and heating the house at 6pm.
Solar installers talk about system size, payback periods, and annual generation figures. But they rarely mention the single biggest factor that determines your actual bill savings: self-consumption. That's the percentage of solar energy you use directly in your home rather than sending it to the grid.
Self-consumption is the metric that separates solar owners who save a fortune from those who wonder why their bills haven't changed. A household with 30% self-consumption uses less than a third of the solar energy it generates. The other 70% gets exported for a small feed-in credit. A household with 70% self-consumption uses most of what it generates, dramatically reducing the amount of expensive grid power it needs to buy.
The difference in real money? A 6.6kW system in a typical household might save $400 a year at 30% self-consumption. Push that to 70% and you could be saving $900 to $1,200 a year from the same panels, with no extra hardware. The panels haven't changed. The weather hasn't changed. The only thing that changed is when you used the electricity.
Not all appliances are equal when it comes to solar shifting. The ones that matter most are "flexible loads": appliances that draw a lot of power but can run at any time of day without affecting your routine.
Running your dishwasher at 7pm instead of 11am can be the difference between free solar power and full-price grid power. Multiply that across your washing machine, dryer, pool pump, and EV charger over a whole year and the numbers add up fast.
If you've read any solar advice, you've probably heard "run your appliances during the day." That's directionally correct but far too vague to be genuinely useful. Here's why:
What you actually need isn't a rule of thumb. You need a forecast that predicts your specific solar production each day, accounting for your panels, your location, and the weather.
Solar forecasting uses real weather data (cloud cover, temperature, humidity, atmospheric pressure) combined with your panel configuration (capacity, tilt, orientation) and geographic location to calculate exactly how much energy your system will produce throughout each day.
Instead of guessing whether today is a good day to run the dryer, a forecast tells you: "Your panels will produce 28 kWh today. Peak output of 4.2 kW will be between 10:30am and 1:00pm. Best time to start your washing machine: 11am."
That level of specificity is the difference between vague advice and actionable savings.
If you own an electric vehicle or plug-in hybrid, solar-aligned charging is where the biggest savings hide. An EV charger draws 2 to 7 kW continuously, which can consume your entire solar output for hours. Charging during peak solar instead of overnight can save $500 to $1,500+ per year in electricity costs alone.
Many EV owners plug in when they get home at 6pm and charge overnight on expensive grid power. Simply shifting that charge to the middle of the day (when the car is at home on weekends, or using a timer on weekdays) can cut your charging costs by 70-80%.
Home batteries like the Tesla Powerwall solve the timing problem by storing solar energy for use in the evening. They work well, but they're expensive: typically $10,000 to $18,000 installed. The payback period can be 7 to 12 years.
Smart appliance scheduling achieves a similar outcome for free. You won't eliminate evening grid usage entirely, but shifting your biggest loads into the solar window captures the majority of the available savings without any capital investment. It's the first step every solar household should take, whether or not you plan to add a battery later.
OnSun is a solar forecasting app that gives you a personalised 7-day production forecast based on your specific panels, location, and local weather. It recommends the best times to run each appliance and shows you how much of your solar energy each load will consume.
No special hardware. No monitoring equipment. Just enter your system details, add your appliances, and start planning. OnSun works with any grid-connected solar PV system, anywhere in the world. Start with 3 days of forecasts free — upgrade to 7 days whenever you're ready.
OnSun gives you everything you need to stop wasting solar energy and start cutting your electricity bills.
.png)
Download OnSun and see exactly when to run your appliances for maximum savings. Your first 3 days of forecasts are free. No hardware needed.
Android coming soon
For more common questions, see our solar savings FAQ.