One of the most common calls we receive from Palm Desert homeowners who already have solar starts with the same question: “I have solar, so why is my electric bill so high?” The immediate reaction is usually to blame the solar system. Sometimes that is exactly what is happening. An inverter may have failed, a breaker may have tripped, a solar circuit may be offline, or another component may have stopped working.
But a high electric bill does not automatically mean your residential solar system is broken. Your home could simply be consuming significantly more electricity than it did when the solar system was originally designed. In many cases, it is actually a combination of both. The solar system may be producing less electricity than it did several years ago while the home is simultaneously consuming more.
So how do you figure out which one is happening? There is a process we use when evaluating these situations, and one of the first things we want to know is surprisingly simple: Did your electric bill increase suddenly, or did it increase gradually? That question can tell us a lot.
Diagnosing the Problem: Start with the Pattern of the Electric Bill
Before climbing onto the roof or replacing any solar equipment, look at your utility bills. Do not just look at the most recent bill. Look at the pattern. If possible, compare several years. We want to determine whether there was a sudden change or a gradual increase. Those 2 patterns usually point us in different directions.
A Sudden Increase on Your Bill Can Point to a Solar Problem
Imagine your electric bills have been relatively consistent for years. Then suddenly, within one billing cycle, your electricity charges increase dramatically. Maybe you normally have a relatively small True Up balance and suddenly you are on track for a much larger one. Or maybe your monthly electricity usage from the utility suddenly jumps even though nothing major changed inside your home. That is when we start looking very closely at the solar system. A sudden change can indicate that something stopped working.
Common solar problem examples include:
- A solar breaker tripped
- The inverter failed
- A solar circuit stopped producing
- A disconnect was turned off
- An optimizer or microinverter problem occurred
- A communication or equipment failure developed
- One or more strings stopped producing
- The entire solar system shut down
If your solar system was producing 40 kWh per day and suddenly starts producing almost nothing, your home still needs electricity. The difference is that the electricity now has to come from the utility. That can show up on your bill very quickly.
This Is Why Solar Monitoring Is So Important
One of the most valuable features of a modern solar system is monitoring. Monitoring gives you visibility into what the system is doing. Instead of waiting for an electric bill to tell you something went wrong, you can potentially see the problem much sooner.
Depending on your equipment, you may be able to see:
- Daily solar production
- Weekly production
- Monthly production
- Historical production
- Individual inverter information
- Panel or optimizer level production
- Battery charging and discharging
- Home consumption
- Grid imports
- Grid exports
When we look at solar monitoring, the shape of the production chart can sometimes tell us just as much as the total production number. A healthy solar production curve on a clear day generally increases through the morning, reaches its strongest production around the middle portion of the day, and then decreases as the sun gets lower.
If that curve suddenly changes, it gives us a clue. Maybe the system is cutting out at a certain time. Maybe production is dramatically lower than it used to be. Maybe part of the array is producing while another part is not. Maybe the inverter is not reporting anything at all. Those patterns help us determine where to start troubleshooting.
What If You Do Not Have Solar Monitoring?
This is common with older solar systems. A homeowner may have installed solar 10, 15, or even 20 years ago. The original monitoring system may no longer work. The installer may no longer be in business. The homeowner may not have access to the account. Or the equipment may never have had the type of detailed monitoring that newer systems provide.
In that situation, the system may need to be physically tested. With an older string inverter system, for example, a qualified solar or electrical technician can evaluate the DC strings and other system components. We may need to verify voltage and current and compare the measurements against what we expect from the system design and current conditions. That can reveal problems that are not obvious just by looking at the inverter.
You Can Lose Part of a Solar System Without Losing All of It
This is something homeowners often do not realize. A solar system does not always fail completely. Sometimes only part of it fails. Imagine a solar array divided into 3 sections. If one section stops producing, the other 2 may continue operating. From the homeowner’s perspective, the solar system still looks like it is working. The inverter is on. There may be a green light. The monitoring app may still show solar production. But you could have lost roughly a third of the system’s potential production, depending on how the system is configured and what failed. That missing production adds up.
You may not notice it immediately. But over several months, that lost energy can translate into substantially more electricity being purchased from the utility. This is why we do not consider: “The inverter is on.” to be the same thing as: “The solar system is producing correctly.” Those are 2 different things.
A Gradual Increase Usually Requires a Different Investigation
Now imagine a completely different situation. Your electric bill did not suddenly increase. Instead, your True Up was $200 several years ago. Then it became $500. Then $800. Then $1,200. Now it is significantly higher. There was no single month when everything changed. The problem developed slowly. When we see that pattern, we start looking at both sides of the equation: How much electricity is the solar system producing? And: How much electricity is the home consuming? A gradual increase can indicate that solar production is declining, household consumption is increasing, utility rates are changing, or some combination of all three.
Your Home May Use More Electricity Than It Did When You Installed Solar
This is one of the most overlooked reasons for high electric bills after solar. Suppose your solar system was installed 8 years ago. At the time, your house consumed: 10,000 kWh per year. The solar system was designed around that consumption. Now your home consumes: 15,000 kWh per year. The solar system may be operating exactly as designed. It is simply no longer large enough for your current energy usage.
A lot can change inside a home over 5, 10, or 15 years. You may have added an electric vehicle. You may have installed a swimming pool. Your children may have gotten older. More people may live in the house. You may work from home now. You may have added another refrigerator or freezer. You may have installed new electronics. You may have added an ADU. You may have changed your air conditioning habits. You may have replaced gas appliances with electric equipment. Or you may simply be using the house differently.
Homes Are Becoming More Electric
Even though appliances and electronics continue becoming more efficient, we are also asking electricity to do more. Electric vehicles are a perfect example. A household that purchases an EV and charges primarily at home can add thousands of kWh of annual electricity consumption. Solar installed before the EV was purchased was not necessarily designed to account for that additional load. The same concept applies to electrification throughout the house. More of our transportation, appliances and household systems are moving toward electricity. That can be great when the home’s energy system is designed around it. But it also means homeowners need to periodically reevaluate whether their original solar system still matches their consumption.
Your Solar System Can Also Produce Less as It Ages
At the same time your household consumption is increasing, your solar system may not be producing exactly what it did when it was brand new. Solar panels gradually degrade over time. Equipment ages. Inverters can lose efficiency or fail. Optimizers and microinverters can develop problems. Connections can fail. Trees grow and create new shading. Panels become dirty. Roof conditions change. Equipment can stop communicating. One or more circuits can fail. That creates a situation where both sides are moving in the wrong direction. Your house may be consuming more while your solar system is producing less. That is one of the most common explanations for a gradually increasing electric bill.
Compare Consumption and Production Separately
This is where homeowners need to be careful when reading utility bills. Your utility bill does not necessarily tell you how much electricity your solar system produced. Imagine your solar system produces 30 kWh during a particular day. Your house immediately consumes 20 kWh of that electricity. Only the remaining 10 kWh gets exported to the utility. The utility meter does not necessarily see all 30 kWh of solar production as an export. That is why utility data and solar monitoring data serve different purposes.
When diagnosing a high bill, we ideally want to know:
- Total household consumption
- Total solar production
- Electricity imported from the grid
- Electricity exported to the grid
Once we have those numbers, the picture becomes much clearer.
Utility Rates Can Also Increase Your Bill
There is another factor that has nothing to do with your solar equipment or household consumption. Utility rates and rate structures change. This is particularly important for California solar customers on Time of Use rates. The value of electricity can depend on when you consume it and, depending on your solar program, when you export it.
If the electricity you purchase during expensive evening periods becomes more costly while the value of the electricity you send back during other periods does not increase at the same rate, the difference between those 2 values becomes larger. That can increase your bill even if your solar system continues producing. This is also one of the reasons battery storage has become increasingly important. Instead of exporting excess solar during the day and buying electricity back later, batteries can allow homeowners to store more of their own solar production and use it later. The exact economics depend on your utility, rate plan and net metering program.
How We Diagnose a High Electric Bill
When someone calls us and says their solar is no longer covering their electric bill, we do not immediately recommend adding more panels. We first want to figure out why the bill increased. The process generally looks like this.
First, we look at the timeline. Was the increase sudden or gradual? Second, we review solar production. Is the system currently producing? How much did it produce over the last 12 months? How does that compare with previous years? Third, we review household electricity consumption. Has the homeowner added an EV, pool, HVAC equipment or another major electrical load? Has annual consumption increased? Fourth, we inspect the solar equipment when necessary. Are all strings producing? Are all circuits operating? Is the inverter functioning correctly? Are there equipment errors? Is shading affecting the array? Finally, we review the utility billing situation. What rate plan is the homeowner on? What NEM program applies? When is electricity being imported? When is electricity being exported? Once those questions are answered, we can usually determine what is actually happening.
Do Not Automatically Add More Solar Panels
This is important. If your bill suddenly increased because your inverter failed, adding more solar panels does not fix the actual problem. Fix the inverter. If one third of your solar system stopped producing because a string failed, repair the system. If the system is working perfectly but your household electricity consumption increased by 40 percent, then additional solar may make sense. If the system produces enough annual electricity but you are buying expensive electricity at night, battery storage may be part of the solution. And sometimes the answer is a combination of additional solar and battery storage. The solution should follow the diagnosis. Not the other way around.
The Pattern of Your Bill Tells a Story
If you remember only one thing from this article, remember this: A sudden increase and a gradual increase usually tell us different things. A large, sudden jump should make you investigate whether something stopped working. Check your monitoring. Check the inverter. Look for alerts. Have the system inspected if necessary. A gradual increase should make you look at the bigger picture. Compare several years of household consumption. Compare several years of solar production. Look at what changed inside the home. Look at the age and condition of the solar system. Review your utility rate plan and net metering agreement. And remember that multiple things can be happening at the same time.
The Bottom Line: Changes in Your Electric Bill are Nuanced
Having solar does not guarantee that your electric bill will remain exactly the same forever. Your house changes. Your electricity consumption changes. Utility rates change. Net metering programs change. And your solar equipment ages.
If your electric bill suddenly increases, there is a stronger reason to investigate an immediate solar production problem such as an inverter failure, tripped breaker, failed circuit or other equipment issue. If the bill gradually increases over several years, the explanation is often more complicated. Your home may be consuming more electricity. Your solar system may be producing less. Utility rates may have changed. And all three can happen simultaneously.
At Supreme Solar and Electric, when our Palm Desert residential solar technicians evaluate a high electric bill, our goal is not simply to sell someone more solar. We want to determine what is actually causing the problem. We can review the home’s electricity consumption, analyze solar production, inspect the existing equipment, test older systems when monitoring is unavailable, identify underperforming circuits or components, and compare the system’s production against what the home actually needs today. Because before you spend money adding solar panels, installing batteries or replacing equipment, you should know exactly why your electric bill went up in the first place.