Your electric bill is still high after going solar. Here is how to find out why.

By Olivier Beauchemin · 2026-08-18 · v1

Your electric bill is still high after going solar, and you're starting to wonder whether you got sold a story. You're not imagining it and you're not alone. Massachusetts homeowners filed more than 200 complaints against solar installers with the Attorney General in a single year, and "promised savings not materializing" was one of the named categories.

I went solar in Massachusetts myself, and I built OwlWatt because my installer couldn't answer my questions about this. What I learned: a high bill after solar has three real causes, and you can tell them apart. Fifteen minutes with two documents narrows it down. That matters, because only one of the three gives you something you can make a claim about.

Three causes, and only one of them is worth a fight

1. Your rate structure changed. The panels are fine. What each kilowatt-hour is worth to you moved.
2. Your household is using more electricity than it used to. The panels are fine. The denominator moved.
3. The system is producing less than it was sold to produce. This is the one with a contractual remedy attached.

It is tempting to jump straight to number three, because it's the explanation that feels right when you're angry. Often it isn't the one. And if you accuse your installer of underproduction when the real cause was a tariff change, you've spent your credibility on the wrong argument.

Cause 1: what your kilowatt-hours are worth changed

Solar economics aren't really about production. They're about what the utility credits you for the production. Three things commonly move underneath a homeowner after the contract is signed.

Net metering terms

Under full retail net metering, a kilowatt-hour you export is worth the same as one you buy. Under the successor tariffs that many states have adopted, an exported kilowatt-hour is worth substantially less than a purchased one. If your system was modeled on retail-rate credit and you're now on an export-rate tariff, your panels can be dead on target while your bill savings collapse.

Time-of-use pricing

On a time-of-use rate, the hours when your panels produce the most are often the hours when electricity is cheapest. You export cheap and buy back expensive. Same panels, same sunshine, different bill.

Fixed charges and minimum bills

Part of your bill has nothing to do with how many kilowatt-hours you used: customer charges, distribution minimums, and in some territories a demand or grid-access charge aimed at solar customers. Solar doesn't touch those. If you were told your bill would go to zero and you're staring at $28 every month, read the fixed-charge lines on the bill before you conclude the system is broken.

Cause 2: you're using more electricity than you were

Nobody likes this one, and it's true a lot of the time. Solar installs cluster with other changes: an electric vehicle, a heat pump, a finished basement, a new baby, someone starting to work from home. Any one of those can add several thousand kilowatt-hours a year.

The check is simple. Find your total annual consumption for the year before the install and for the last twelve months. Consumption, not cost. If you were using 9,000 kilowatt-hours a year and you're now using 14,000, the system is covering a load it was never sized for. That's a sizing conversation, not an underproduction claim.

Cause 3: the system is producing less than it was sold to produce

Now the one you came here for. To judge it you need two numbers, and almost every homeowner only has one.

The number you have is actual production. Your monitoring app reports it. Add up the last twelve months.

The number you need is expected production: what a system with your panel count, your orientation, your tilt, your shading and your location should have produced under the weather that actually happened over those twelve months. Not the proposal number. The proposal was modeled against a long-run average weather year, before your system existed. If the last twelve months came in cloudier than that average, a shortfall against the proposal is weather, not fault.

That difference is why an app showing you below your estimate isn't a claim yet. An expected-output figure computed against the real historical weather for your location is what turns a complaint into evidence. It comes from the open-source model the National Renewable Energy Laboratory publishes, run against your actual system geometry. We walk through the whole calculation in how OwlWatt measures your system.

Why your monitoring app won't tell you this

Your installer's app and your inverter portal both answer one question: are the panels reporting? Neither answers whether they should have produced more. A system can sit at green every day and still run twenty percent low, because two strings face a direction nobody modeled or because a tree grew. Green means reporting. It doesn't mean correct.

One more thing, bluntly. The company that sold you the system is the company whose app tells you how the system is doing. That isn't a conspiracy, but when money is on the line you want a number that doesn't come from them.

What the gap is worth, in your own numbers

This part is arithmetic you can do at the kitchen table, so do it with your own figures. Say a system was sold to produce 10,000 kilowatt-hours a year, and say power costs $0.30 per kilowatt-hour. Both are examples: use your own estimated annual production, and take your own rate straight off your bill. A shortfall costs you this much over a year.

OwlWatt costs $9.99 a month, or $87.89 a year. Even the 5% row comes to more than that in a single year. At 10%, the gap is roughly three and a half times what the subscription costs.

And here's what changes the size of this. Most production guarantees are measured over a contract year, assessed at each anniversary. So 10% under isn't a one-time $300. It's $300 this year, and again next year, for as long as it stays under and the guarantee runs, often ten to twenty-five years. Ten years of that is $3,000. Whether each year is separately claimable depends on your contract.

Now the honest part. OwlWatt doesn't recover that money for you. We measure the gap and document it with dated evidence. Whether a claim goes anywhere depends on what your contract says and, if it gets that far, on a licensed attorney in your state. So read those figures as what's at stake and what you currently can't see, never as what you'll get back.

And the honest answer may be that you have no meaningful gap at all. Plenty of systems check out fine. Finding that out has real value too, because it lets you stop suspecting the panels and go deal with your rate structure instead.

Running this in the wrong order costs you, and it is worth saying why. Going straight to step three is tempting, because underproduction is the answer you want it to be when you are annoyed. But walking into a conversation with your installer without the first two steps behind you means you cannot answer the first question they ask, and you have spent credibility you will want later. Steps one and two take an afternoon.

What a production guarantee actually promises

If your contract has a production guarantee, read the clause itself rather than the sales summary of it. Most follow a common shape: the installer commits that actual output will land within some percentage of estimated output, commonly ninety percent, and if it falls short they owe you either a cure or a payment for the shortfall kilowatt-hours at a stated rate.

Three details decide whether a shortfall is collectible:

• The threshold. Ninety percent of estimate means a nine percent shortfall triggers nothing.
• The measurement window. If yours is defined as a full contract year, one bad month will not trigger it.
• The exclusions. Look for carve-outs covering shade that existed at signing, weather, grid outages and homeowner-caused issues.

A guarantee isn't a warranty, either. Equipment and workmanship warranties cover things that break. A production guarantee covers output falling short. They're different instruments with different remedies, and mixing them up is the fastest way to get a claim rejected.

The order to do this in, and who does what

Work the diagnosis in order, because each step rules out a cheaper explanation than the next:

1. Rate structure and fixed charges, before versus now.
2. Annual consumption, before versus now.
3. Only if both are steady, expected output modeled against real weather, compared to actual.
4. If the gap survives step three, the guarantee clause checked against its threshold, measurement window and exclusions.
5. The whole thing in writing to your installer, with the numbers attached.

That's what OwlWatt does. You upload your utility bills and connect the monitoring you already have. We read the billing period, the kilowatt-hours and the rate off each bill, so steps one and two happen without you comparing anything by hand, and we compute the independent expected-output figure for step three. If a gap survives that, it comes out as a claim report with the inputs, the method and the dated evidence attached.

We're independent of your installer by design. We don't install, we sell no equipment, and we take no referral fees from installers, which is why the number holds up when you put it in front of yours.

You could do steps one and two yourself this afternoon with two bills, and some people will want to. Step three is the one nobody can do alone, and it's the one that decides whether you have a grievance or a claim.

If you haven't signed yet, the assumptions to interrogate are in what to check before you sign a solar contract, and the modeling optimism behind inflated savings numbers is in why your solar savings calculator was wrong.