guide5 min read

Illinois Net Metering Changed in 2025 — What It Costs You and How to Protect Your Savings

Ryan Cook•June 19, 2026

If you've been reading older solar guides for Illinois, there's a good chance they're describing a program that no longer exists. On January 1, 2025, the state ended full retail net metering for new solar customers. I still talk to homeowners who think they'll get paid the full rate for every kilowatt-hour they send to the grid. That deal is gone. Let me explain what replaced it and, more importantly, what you do about it.

What Actually Changed

Under the old rules, full retail net metering meant every unit of electricity your panels exported to the grid earned a credit worth the entire retail rate — supply, delivery, and transmission combined.

Under the new model, called net billing, new customers are credited only for the supply portion of exported electricity. The delivery and transmission pieces are no longer credited on what you send back.

The practical effect: the credit for the surplus you export is worth roughly half of what it used to be.

Let me be clear about what this does not touch, because the headlines get it wrong. The power your panels make that you use right now, in real time, still offsets electricity at the full rate. Net billing only reduces the value of the extra you push back onto the grid. That distinction is the whole game.

What It Costs You — In Plain Terms

Say your panels make more than you're using at noon on a sunny day. That surplus flows to the grid. Under the old rules, you banked a full-rate credit and pulled it back later at night for free. Under net billing, you bank a smaller credit for that surplus, then buy nighttime power back at the full rate, delivery charges and all — the same charges you weren't credited for on the way out.

So the leak is the gap between what you're paid for exports and what you pay to buy power back. Overbuild a system for big export credits the old way, and a chunk of that value now drains out through that gap.

The fix isn't to give up. It's to stop designing systems for a program that ended.

Before and after chart showing a kilowatt-hour exported to the grid earned full retail credit before 2025 but only the supply portion under net billing, plus three ways to protect savings: right-size, add a battery, self-consume

How to Protect Your Savings

Three moves keep your savings intact under net billing:

1. Right-size the system. Instead of overbuilding to sell big surpluses, you size closer to what your home actually uses. More of your production gets consumed on-site at full value, less gets exported at the reduced credit. Our calculator estimates the right size for your usage →

2. Add battery storage. A battery stores your extra daytime production and lets you use it at night, instead of selling it back cheap and buying it back at full price. Storage went from "nice to have" to "often worth it" the day net billing started. It also keeps your lights on during outages, which matters more every year as data center demand strains the Illinois grid. On many of our leases, battery backup is included or available for a modest monthly add. No big upfront check. Here's a deeper look at solar battery backup in Illinois.

3. Understand the smart inverter rebate trade-off. Both Ameren and ComEd offer a one-time rebate for systems with storage and a qualifying smart inverter. In Ameren territory especially, taking that rebate can change how your credits are calculated. Whether the rebate or the higher export credit wins depends on your specific setup, so it's worth running both before you decide.

Ameren vs. ComEd — A Quick Note

The net billing framework applies statewide, but the dollars differ because the rates differ. ComEd's all-in rate runs higher (around 17¢/kWh on average), so self-consumed solar is worth more per kilowatt-hour there. Ameren's summer rates spike hard (around 20¢/kWh), which makes summer self-supply especially valuable in central and southern Illinois. The ComEd rate breakdown and Ameren rate breakdown show the full picture for each territory.

My Take

The 2025 net metering change made a lot of people think solar in Illinois got worse. I see it differently. It got more dependent on doing it right.

The old full-retail program was forgiving. You could overbuild and still come out fine. Net billing rewards a system sized for your home, with storage that captures your own production. Designed well, the savings are still very real, because the thing driving those savings — rising utility rates — keeps getting worse, not better.

Designed poorly, you leave money on the table. That's the actual risk now, and it's why I'd rather walk you through the design than have you guess. Check what your roof can do or get a free, no-pressure estimate.

Ryan Cook is the founder of Ltd Solar Consulting, helping Illinois homeowners compare solar options across Ameren and ComEd territory. Questions about net billing? Get a free quote or call (618) 217-2001.

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Frequently Asked Questions

On January 1, 2025, Illinois ended full retail rate net metering for new solar customers and switched to a net billing model. Under the old rules, every kilowatt-hour your panels sent to the grid earned you a credit worth the full retail rate — supply plus delivery plus transmission. Under net billing, new customers are credited only for the supply portion of that electricity, not the delivery and transmission charges. In practical terms, the credit for energy you export is worth roughly half of what it was before. This doesn't affect the power you use directly from your panels in real time — that still offsets electricity at the full rate. It only reduces the value of the surplus you send back to the grid. It's a meaningful change, but as we explain below, it changes how you should design a system more than whether solar still makes sense.

No — it means you design the system differently. The change only reduces the value of surplus electricity you export to the grid, not the power you consume directly from your panels. So the strategy shifts toward using more of what you produce on-site. That's done two ways: right-sizing the system so it more closely matches your actual usage instead of overbuilding for big export credits, and adding battery storage so extra daytime production is stored and used at night instead of sold back at the lower credit. Meanwhile, the savings side keeps getting stronger — Illinois utility rates are up roughly 90% in five years, so every kilowatt-hour you self-supply is worth more each year. Net billing trimmed one piece of the value, but rising rates more than offset it for most homes.

The smart inverter rebate is a one-time payment from your utility for installing a solar system with battery storage and a qualifying smart inverter — equipment that can support the grid and respond to its needs. Both Ameren and ComEd offer versions of it, paid per kilowatt of installed capacity. There's an important trade-off to understand in Ameren territory: taking the smart inverter rebate can affect how your net metering credits are calculated, so it isn't automatically the right choice for every home. Whether the rebate or the higher export credit nets out better depends on your system size, your battery, and how much you export. This is exactly the kind of detail that's easy to get wrong on your own, and getting it wrong can cost you. It's worth having someone run both scenarios before you commit.

Since the net metering change, batteries make more sense for more Illinois homes than they used to. Under net billing, surplus power you export earns a reduced credit, so storing that surplus and using it yourself at night — instead of selling it back cheap and buying it back at full price — protects more of your savings. A battery also keeps essential circuits running during an outage, which matters more every year as the grid gets strained by data center demand and capacity shortfalls. On many of our leases, battery backup is included or available for a modest additional monthly amount, so you don't have to pay thousands upfront to get it. A battery isn't mandatory, and a well-sized system without one can still save money — but the 2025 rule change tilted the math toward storage for a lot of households.

If your system was interconnected and operating under full retail net metering before the January 1, 2025 cutoff, you were generally allowed to keep those terms for a defined period under the transition rules — existing customers weren't immediately flipped to net billing. New customers connecting in 2025 and later fall under net billing from the start. Because the transition details and grandfathering windows have specific dates and conditions, you shouldn't assume your situation from a blog post — including this one. If you already have solar, check your interconnection paperwork or ask your utility what rules apply to your account. If you're shopping for a new system now, plan around net billing, because that's the framework you'll be designing within. We can walk through exactly what applies to your address and utility.