Why Is Your Electricity Bill Still High With Solar? A Perth Owner’s Guide
Your Solar Bill Troubleshooting Guide - Made Easy
Solar Bills
Solar is supposed to make your electricity bill boring. So when the Synergy bill lands and it is higher than you expected, something in the chain is not doing its job. It might be the system, it might be the way your household uses power, or it might be the bill itself. This is one of the most common calls we take at Hughes Electrical, and in almost every case the cause falls into one of five categories.
This guide walks through each one in the order we check them on a real callout. Work through them in the same order and you will usually find your answer. If the trail leads back to the system itself, our solar maintenance service exists for exactly this situation.
Start With One Question: Is the System Actually Generating?
Before anything else, open your inverter app and compare this month’s generation against the same month last year. That single comparison rules half the possible causes in or out. A healthy 6.6kW system in Perth should produce roughly 28kWh a day averaged across the year, more in summer and less in winter. If your numbers are close to last year’s, the system is fine and the answer sits in how your household uses power or how you are billed. If generation is clearly down, or the app shows nothing at all, the system is the problem.
Plenty of Perth homes run for months on a system that has partially or completely stopped generating. The inverter does not sound an alarm you can hear from the kitchen. It just quietly stops, and the grid picks up the slack at full price. The bill is often the first symptom anyone notices.
Cause 1: Your System Is Underperforming
If generation is down on last year, these are the usual suspects, roughly in the order we find them.
Dirty panels. Perth summers coat panels in dust and pollen, and low winter rainfall means rain does not wash it off the way people assume. A soiled array can lose a meaningful share of its output, and the loss lands in the exact months the system should be earning its keep. Coastal homes collect salt film on top of the dust and get hit harder.
An inverter fault or derating. Inverters are the hardest working component in the system and Perth heat pushes them harder still. An inverter running in limited output mode, or tripping intermittently on hot afternoons, drags down generation without fully switching off. Check the display or app for fault codes and warning lights.
A tripped isolator or failed DC connector. A DC isolator that has tripped, or a corroded rooftop connector, can drop an entire string of panels. On a two string system that is half your generation gone overnight, and the inverter app can look almost normal at a glance.
New shading. Trees grow. A branch that cleared the array at install can be shading two panels by year four, and on older string systems the shaded panels drag down the whole string.
Panel degradation or failure. Quality panels lose well under one percent of output per year. Budget panels can degrade much faster, and a single hot spotted panel can pull a whole string down with it.
Every one of these is found and fixed in a standard service. If your generation figures are down and you cannot see an obvious cause from the ground, book a solar maintenance visit rather than climbing up to investigate. The DC side of a solar array is live in daylight and runs at voltages that can kill.
Cause 2: You Are Using Power at the Wrong Times
This is the cause most Perth owners have never had explained to them. Synergy’s buyback scheme pays around 10 cents per kWh for exports between 3pm and 9pm, and only around 2 cents outside that window. Meanwhile, power you buy from the grid costs upwards of 30 cents per kWh.
Read those numbers together and the problem is obvious. If your household exports solar all day at 2 cents, then comes home at 6pm and buys power back at more than 30 cents to run the oven, the air conditioner and the washing machine, your solar is earning cents while your usage costs dollars. The system can be generating perfectly and the bill barely moves.
The fix costs nothing. Run the dishwasher, washing machine and pool pump on timers through the middle of the day. Pre cool the house with the air conditioner in the afternoon while the panels are producing, rather than working it hard at full price after sunset. Heat hot water during the day if your setup allows it. Households that make this shift routinely cut hundreds of dollars a year off their bills without touching the hardware.
Cause 3: Your Usage Has Grown
A solar system is sized for the household it was designed for. Households change. A new pool pump, a spa, ducted air conditioning running hard through summer, an electric vehicle charging in the garage, teenagers who were toddlers when the panels went in. Any of these can add more daily consumption than the system was ever sized to offset.
Compare the total kWh consumed on your current bill against the same billing period two or three years ago. If consumption has climbed while generation has stayed flat, the system is not failing. It has been outgrown. Depending on roof space and inverter capacity, the answer might be extra panels, a larger system or a battery that shifts your excess daytime generation into the evening. Our residential solar page covers the options, and sizing advice from a licensed electrician costs a lot less than years of oversized bills.
Cause 4: The System Was Too Small From Day One
Some systems were undersized on day one, usually because the quote was built around a price point instead of the household’s actual usage. A quick check: divide your average daily consumption in kWh by 5.3, which is Perth’s average peak sun hours. That is roughly the system size in kW your household needs. A family using 25kWh a day needs around a 5kW system just to break even on paper, and comfortably more in practice because generation and usage never line up perfectly.
If your system is well under that number, no amount of servicing or habit changing will get the bill where you want it. The system is doing everything it was built to do. It was just never built to cover your usage.
Cause 5: The Problem Is on the Bill, Not the Roof
Sometimes the system and the household are both fine and the bill itself is the issue. Check that the bill is based on an actual meter reading rather than an estimate, because estimated reads can overshoot badly and correct themselves later. Check the daily supply charge and your tariff, since supply charges apply no matter how much solar you generate and they rise over time. And if you have recently had meter or switchboard work done, confirm the meter is registering your exports at all. A metering fault can silently erase your feed in credits.
Line up three things: generation from your inverter app, exports and imports from your Synergy bill, and your total consumption. If generation is healthy but the bill shows little or no export credit, the fault sits in the metering or billing chain and is worth a call to your retailer.
The Five Minute Check Before You Call Anyone
Open the inverter app and compare generation against the same month last year. Look at the inverter for fault codes or warning lights. Check the bill is an actual read, not an estimate. Compare total consumption against the same period last year. And think about whether anything new and hungry has been plugged into the house since the system went in.
Those five checks take five minutes and will tell you which of the causes above you are dealing with. If the trail points at the system, that is where we come in.
How a Solar Health Check Fixes a High Bill
A solar health check from a licensed electrician answers the question this article can only help you narrow down. We pull your actual production data and compare it against what the system should generate for the time of year. The inverter is checked for faults, derating and pending software updates. Isolators are tested, rooftop connectors and mounting hardware are inspected, and panels are assessed for soiling, shading and damage. Where cleaning is needed, panels are cleaned to manufacturer specification.
The visit ends with a written report on system condition, what was fixed and what to watch. If the real answer is behavioural, we will tell you that too, along with which appliances to shift into daylight hours. You get a clear answer on why the bill is high instead of another season of guessing.
Book a Solar Health Check with Hughes Electrical Group
If your generation is down, your inverter is showing faults, or you simply want a licensed electrician to confirm the system is doing what it should, book a solar maintenance service with us. We work on systems we installed and systems installed by others, and every visit ends with a written report on system condition, performance and anything that needs attention.
Phone 0437 206 869, email info@hugheselectrical.au, or request a quote online. We are based in Myaree and we service across the Perth metro area. For more on how we approach solar generally, see our SmartSolar page.
