What to Know About Solar Panels in St. Louis

Revised August 20, 2026

Imagine it’s a Saturday morning in Affton and there’s a guy on your porch with a tablet, telling you your roof faces the right way and you’ve already been pre-approved. Two weeks ago your cousin in Florissant got the same knock. A neighbor in Kirkwood put panels up three years back and won’t stop talking about how good it was. Somebody in Belleville took theirs down last spring and gets quiet when you ask why.

All four of those can be true at once, which is why this is so hard to research. Solar here isn’t one product with one answer. It’s a roof question, an insurance question, a utility-tariff question and a resale question stacked on each other — and the tax rules underneath all of it changed less than a year ago.

So here’s the honest version, sources named and dated, no pitch. If you read one section, read the next one. It holds the fact most likely to be wrong in whatever quote is sitting on your kitchen table.

Is the 30% solar tax credit going away in 2026?

It already went away. The 30% federal Residential Clean Energy Credit — Section 25D, the one homeowners claimed on their own tax return — does not apply to a system finished after December 31, 2025. The IRS page for the credit, last reviewed or updated July 4, 2026, states flatly that the credit “is not available for any property placed in service after December 31, 2025.”

The change came from Public Law 119-21, signed July 4, 2025. The IRS then issued fact sheet FS-2025-05 on August 21, 2025, spelling out the timing trap: an expenditure “is treated as made when the original installation of the item is completed.” Not when you signed. Not when you paid the deposit. If installation wrapped up in 2026, the IRS treats the expenditure as made in 2026, and there is no 25D credit to claim. The companion Section 25C credit for insulation, windows and efficient HVAC ended on the same date. So if anyone quoting you in 2026 subtracts a 30% federal credit from your purchase price, that quote is wrong. Verify it yourself at irs.gov before you sign — this is a five-figure decision that deserves ninety seconds of checking.

Two things did survive, and pitches blur them together on purpose. First, the business-side clean electricity investment credit, Section 48E, was not repealed on the 25D schedule. That is the credit a leasing company or PPA fund claims on equipment it owns and puts on your roof. You never claim it and it never appears on your return. Second, Illinois still runs state-level solar programs, which is a genuinely different situation from Missouri. If you did finish an installation in 2025, ask a CPA about carrying an unused amount forward; the IRS describes 25D as nonrefundable with carryforward of unused amounts, but how that lands on your return is a question for your own preparer.

Is solar worth it in Missouri?

In Missouri it now hinges almost entirely on how much of your own power you use the moment you make it, because Ameren Missouri does not buy your surplus at retail. Its customer-owned solar page, checked August 2026, credits excess generation at 3.84 cents per kWh in summer (June through September) and 3.39 cents per kWh in winter (October through May). Every kWh your house consumes while the panels are making it is worth full retail to you. Every kWh you export comes back at roughly four cents. That spread is the whole Missouri argument, and it is why storage, load shifting and running the dryer at 1 p.m. matter more here than in retail-buyback states.

The rules sit in the Missouri Net Metering and Easy Connection Act, RSMo 386.890, with the Public Service Commission rule at 20 CSR 4240-20.065. As the Missouri Department of Natural Resources explains, the program covers systems up to 100 kW, credits excess at the utility’s avoided fuel cost, and bars a utility from charging “any additional standby, capacity, interconnection or other fee or charge that would be unique to a customer generator.” For systems of 10 kW or less, no extra liability insurance or additional distribution equipment can be required. Utilities must answer an application within 30 days for systems 10 kW and under, or 90 days up to 100 kW.

Nothing is left on the incentive side either. Ameren Missouri’s solar rebate ran under RSMo 393.1670 at 50 cents per watt for systems operational between January 1 and June 30, 2019, then 25 cents per watt through December 31, 2023 — and it ended there. Add the repealed federal credit and a Missouri homeowner buying outright in 2026 has no federal credit, no state credit and no utility rebate. The sunshine is unchanged; the subsidy stack is not.

One more wrinkle worth a call to your county assessor. RSMo 137.100 lists “solar energy systems not held for resale” among exempt property, but the Missouri Supreme Court held that exemption unconstitutional in Johnson v. Springfield Solar 1, LLC, docket SC99441, decided August 9, 2022. That case involved a commercial facility in Greene County, and how assessors treat a residential rooftop array varies — ask St. Louis County, St. Charles County or Jefferson County directly. To run your own numbers, pull twelve months of Ameren statements, total the dollars, total the kWh, and divide.

How is solar different on the Illinois side of the river?

Illinois is a meaningfully better policy environment than Missouri right now, and the difference is state law, not sunshine. Homeowners in Belleville, Edwardsville, Granite City and O’Fallon sit under Illinois Shines, a state program in which Illinois utilities purchase renewable energy credits from qualified solar projects. The incentive is paid to a state-Approved Vendor and, as the program puts it, “may be passed on to customers as savings.” Missouri has no statewide equivalent.

Net metering there changed recently too. Under the Climate and Equitable Jobs Act, Ameren Illinois applies a new crediting structure for applications after January 1, 2025: excess generation earns credit against the supply and transmission portions of the bill and no longer offsets delivery service charges. Customers who applied before that date keep the older arrangement, and net metering covers systems 100 kW and smaller. In exchange, Ameren Illinois posts a smart inverter, or distributed generation, rebate — for residential DS-1 customers, $300 per kW-DC for the inverter connecting a solar generator and $300 per kWh for an energy storage system inverter. The rebate and the supply-only crediting travel together, so a good Illinois quote shows both sides of that trade in dollars, not adjectives.

Then there is Illinois Solar for All, the income-qualified program for households at or below 80% of area median income. It is the closest thing to genuine no-up-front-cost residential solar in this metro, and its structure requires that a participant’s savings exceed any subscription or loan payment. It is also popular: the program announced that its single-family and two-to-four-unit categories reached capacity in 2025, with residents likely waiting on more funding in 2026. Two houses ten miles apart, one in Webster Groves and one in Granite City, get different answers to the same question.

What is the 20% rule for solar, and is there a 33% rule?

Neither is a law, a tax rule or a utility requirement. Both are internet rules of thumb, and they don’t even carry the same meaning from one website to the next. The 20% rule is usually a sizing buffer — some writers use it to mean building headroom above average usage for cloudy stretches and system losses, others to mean deliberately undersizing. The 33% rule most often refers to fire-code limits on how much of a roof’s plan area an array may cover before extra access pathways and setbacks kick in, and sometimes to oversizing a DC array relative to its inverter. Conversation starters, not standards.

Here is the sizing rule that actually binds you in Ameren Missouri territory, from Ameren’s own customer-owned solar page: most recent 12 billing months in kWh, divided by 8,760 hours times a 15.6% capacity factor, equals your maximum allowable nameplate capacity in kW DC. Ameren’s worked example uses a home at 13,512 kWh a year: 13,512 ÷ (8,760 × 0.156) = 9.887 kW.

Two useful things fall out of that. Your size is anchored to what you have already used, not what you plan to use — so if an EV or a heat pump is coming next year, raise it early, because last year’s bills are the input. And Ameren’s 15.6% capacity factor works out to roughly 1,370 kWh a year for every kW DC installed in its Missouri territory, a utility-published local planning number that beats any national average in an ad. For your address specifically, run the free PVWatts calculator the National Renewable Energy Laboratory publishes at nrel.gov. On roof coverage, what governs your house is whichever fire code edition your city adopted. St. Louis County alone contains more than 80 municipalities, so setbacks and permit fees can differ from one side of a street to the other.

Wildly off-topic — the roof crew will want sandwich shops at noon.

What do St. Louis hail, roofs and tree cover do to a solar system?

Hail is the most underrated line item in a St. Louis solar decision. Using National Weather Service Storm Prediction Center counts of hailstones one inch or larger, the Insurance Information Institute reports Missouri had 253 hail events in 2025 — fifth-most of any state — and Illinois had 167, ninth-most. Texas led with 902, Kansas followed with 375. This is not a distant risk. It is our normal spring.

So call your homeowners carrier before you sign, not after the first storm. Ask three questions and get the answers in writing: is a permanently mounted rooftop array covered as part of the dwelling or does it need its own endorsement; what is my wind and hail deductible, and is it a flat dollar amount or a percentage of dwelling coverage; and does adding an array change my premium, deductible or eligibility at renewal. Percentage wind-and-hail deductibles are common here, and the gap between a $1,000 deductible and 2% of a $400,000 dwelling is not a rounding error.

Roof age is next. A quality array is built to sit up there for decades; shingles in this climate are not. If your roof has fewer than about ten years left, replace it first, or you are buying a future removal-and-reinstall job nobody budgets for at signing. A good local company will tell you to do the roof first and lose the sale — take that as a signal. If you’re pricing materials for that roof job, the counters at St. Louis hardware stores are still good for exactly that kind of question.

Then trees. Older neighborhoods — Webster Groves, Maplewood, Ferguson, big stretches of south city — carry serious canopy, and shading does not cut output in a neat straight line. A branch across one corner of an array in late afternoon can cost far more than its shadow suggests, depending on whether the system uses a string inverter, optimizers or microinverters. Ask for a shade analysis taken on site, tied to your actual roof planes. A satellite screenshot with a sunny-day overlay is a sales graphic, not an engineering study.

Buying, leasing or a PPA — which is which?

Three ways end up with panels on your roof, and they are wildly different assets. You buy with cash or a loan and own it outright. You lease, paying a fixed monthly amount for equipment you do not own. Or you sign a power purchase agreement and buy the electricity the system makes, at a per-kWh rate, from the company that owns it.

Since the homeowner credit ended, far more 2026 offers steer toward leases and PPAs, and there is a real reason for it: Public Law 119-21 repealed residential 25D but left the business-side Section 48E credit standing on a different timetable, so the fund that owns the equipment can still claim a federal credit you cannot. That is legal and normal. The fair question is how much of it is reflected in your monthly payment — ask for the answer as a number. Then get five items in writing: term length, the annual escalator percentage, the buyout schedule year by year, who pays to remove and reinstall the array when your roof is replaced, and what happens at the end of the term. A 2.9% escalator sounds harmless in year one and is a very different number in year eighteen.

Why is it so hard to sell a house with solar panels?

Usually it isn’t the panels — it’s the paperwork bolted to them. A leased or PPA system is a long-term contract sitting on your roof, and it commonly carries a UCC-1 fixture filing recorded against the property. At closing that gets resolved one of three ways: the buyer qualifies with the solar company and formally assumes the agreement, the seller buys the contract out, or the filing is released so title passes clean. Each takes time, in the middle of a purchase contract with a clock running.

An owned, paid-off system is a different story — simply an improvement to the house, like a finished basement. An owned system with a loan against it typically gets paid off at closing like any other lien. The friction concentrates almost entirely in third-party ownership, worth knowing now if there is any chance you move within the decade. Whatever you own, keep a folder from day one: the signed interconnection agreement with Ameren, the permit and final inspection, warranties with registration confirmations, the monitoring login, and the production history. And be skeptical of any resale-premium percentage a salesperson quotes for this metro — there is no current, credible St. Louis-specific figure behind one.

Why are people getting rid of their solar panels?

About seven honest reasons, most of which have nothing to do with solar being a bad idea in principle. A roof needs replacing and the array has to come off. The installer went out of business, so the workmanship warranty is worthless and nobody else wants to touch the system. A lease payment escalated past the value it delivers. An inverter failed after its warranty ended. Storm damage where the deductible ate most of the claim. Production that never came close to the projection, usually from shading or an oversold estimate. And squirrels or birds nesting under the panels and chewing wiring, a common and expensive nuisance in wooded neighborhoods. Worth noting that much of what looks like removal is really removal and reinstall around a roofing job, and the panels go right back up.

Why is my electric bill high if I have solar?

Because solar reduces the energy portion of your bill, not the whole bill. The fixed monthly customer charge stays. Delivery charges largely stay. In Ameren Illinois, for applications after January 1, 2025, excess generation credits do not offset delivery service charges at all. In Ameren Missouri, exported kilowatt-hours come back at 3.84 cents in summer and 3.39 cents in winter, not at what you pay to buy power in the evening.

The other usual suspects: new load that arrived after the system was sized, such as an EV charger, a heat pump or a hot tub; an annual true-up landing in one lump; snow or leaves sitting on the array; and an inverter that faulted out and went unnoticed for weeks because nobody opened the monitoring app. Set a monthly reminder to check production. Then handle the boring load-side work — a house full of old fixtures and bulbs quietly raises the size of system you need, and swapping lighting fixtures costs far less per kilowatt-hour saved than adding panels.

Can you really get free solar panels in Illinois or Missouri?

On the Illinois side something close to it exists and it is real: Illinois Solar for All serves households at or below 80% of area median income, with no up-front cost and a program requirement that savings exceed any subscription or loan payment. It is state-run, works through Approved Vendors, and has run out of room before — both its single-family and two-to-four-unit categories hit capacity in 2025. In Missouri there is no statewide equivalent and no state program giving away residential panels. Nearly every free-solar ad aimed at a Missouri address is a lease or PPA with no money down. That can still work for the right household, but it is financing, not a giveaway, and the word free is your cue to read the contract twice.

What solar installers wish St. Louis homeowners knew

From the other side of the counter, a residential solar company is a sales operation with a construction crew attached, and customer acquisition — not hardware — is the line item that decides whether the shop survives the year. That is why you get knocked on. Because 25D turned on completed installation rather than payment, late 2025 was a scramble to finish jobs by December 31 and early 2026 was the quiet side of that cliff, which is much of why so many companies now lead with lease and PPA offers instead of cash quotes. The other quiet tax is paperwork: with more than 80 municipalities in St. Louis County, the same 8 kW job runs through a different building department, fire official and fee schedule depending on the address. The good operators pull your last twelve months of usage before quoting, and walk away from a roof with five years left in it. That work still has to be findable locally, which is what a complete listing on St Louis Near Me Directory is for.

Frequently asked questions

What is the biggest downside to solar electricity?

It only makes power while the sun is up, so its value depends on what your utility pays for surplus. In Ameren Missouri territory, excess generation is credited at 3.84 cents per kWh in summer and 3.39 cents in winter — far below what you pay after dark. That timing mismatch, not panel quality, is what most often disappoints homeowners here.

How much does a solar system cost for a 2000 sq ft house?

Square footage does not set the price — your electricity usage does. Ameren Missouri sizes systems from your most recent twelve billing months, divided by 8,760 hours times a 15.6% capacity factor, so two 2,000-square-foot houses can need very different arrays. Get three itemized quotes priced per watt installed off the same usage data. Anyone quoting from square footage alone has not read your bills.

What is the 33% rule for solar panels?

A rule of thumb, not a legal standard. Most often it refers to fire-code limits on how much of a roof’s plan area an array can cover before extra access pathways and setbacks are required; sometimes it describes oversizing a DC array relative to its inverter. What governs your roof is the fire code edition your municipality adopted, so ask your installer to name it.

What I wish I knew before getting solar panels?

The four regrets that come up most: not replacing an aging roof first, not calling the insurance carrier about wind and hail deductibles, not grasping that surplus power sells back for pennies rather than retail, and signing a lease without reading the escalator and buyout schedule. All four are avoidable in one afternoon of phone calls before anybody gets a signature.

Can you get free solar panels in Missouri?

No. Missouri has no statewide program that installs residential panels for free, and Ameren Missouri’s solar rebate ended December 31, 2023 under RSMo 393.1670. The federal 25D credit ended for systems completed after December 31, 2025. A free-solar ad aimed at a Missouri address is almost always a lease or power purchase agreement with no money down.

Can you really get solar panels for free in Illinois?

Something close, if you qualify. Illinois Solar for All serves households at or below 80% of area median income, with no up-front cost and a requirement that savings exceed any subscription or loan payment. It runs through state-Approved Vendors and has limited room — the program reported its single-family and two-to-four-unit categories reached capacity in 2025, with more funding expected in 2026.

Will the government pay you to install solar panels?

Not a Missouri homeowner in 2026. The federal residential credit ended for systems placed in service after December 31, 2025, and Missouri has no state credit or utility rebate left. In Illinois, yes indirectly: Illinois Shines has utilities buy renewable energy credits through Approved Vendors, and Ameren Illinois posts a $300 per kW-DC smart inverter rebate for residential customers.

How to apply for free solar scheme in 2026?

If you are in Illinois and income-qualified, apply through an Approved Vendor listed by Illinois Solar for All at illinoissfa.com, and check current capacity first, since categories have filled up before. If you are in Missouri, there is no such program to apply for. Ignore any text message or door pitch claiming a government solar scheme is enrolling your address.

Is solar worth it financially?

That depends on your blended rate, your roof and which state you are in — and the honest answer changed in 2026, when the 30% federal credit ended. Do the math yourself: total the dollars and the kWh across twelve months of bills, divide for your real rate, then estimate how much production you would use on-site rather than export at pennies.

What are 5 disadvantages of solar power?

One, output stops when the sun does. Two, exported surplus is credited well below retail in Ameren Missouri territory. Three, an aging roof has to come off and go back on around the array. Four, hail exposure is real here, with Missouri fifth nationally in 2025 hail events. Five, leased and PPA systems complicate a home sale through recorded fixture filings.

About the Author: The St Louis Near Me Directory Team
Written by a dedicated team of St. Louis locals who live, work, and play right here in the St. Louis metro. Founder Lane Forman and team are committed to building the region’s most trusted directory by verifying listings and connecting local businesses with loyal customers across Missouri and Illinois.

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