Ethan BrooksBy Ethan Brooks

Updated November 2026

Illinois solar net metering is the export credit system most homeowners with rooftop panels are asked to compare against newer, export-based billing. For most households that already run a system sized to their annual use, the older full-retail credit structure still makes the stronger case. Homeowners who plan to oversize their array, or who expect their usage to fall, need to look closer at the newer approach, because the value of each exported kilowatt-hour is set differently. This comparison walks through the two options side by side so you can match the program to your roof, your load and your goals.

Before comparing, it helps to know what each option is. Under the traditional structure, every kilowatt-hour your panels push onto the grid offsets one kilowatt-hour you pull back later, at roughly the full retail rate. Under the newer export-based structure, the utility credits your exports at a lower, time-varying rate, and your system is evaluated on what it sends out rather than what it displaces. If you want the general mechanics first, Solar Net Metering Requirements: What You Need to Qualify (Step-by-Step) covers eligibility, and Solar PV Net Metering Explained: How It Works and Credits Your Bill explains how credits roll through a monthly statement.

Comparison Table

Criteria Traditional Net Metering Export-Based Billing (Net Billing)
Credit value for exports Close to full retail rate, one-for-one offset Lower, varies by hour and season
Monthly excess handling Rolls forward, typically with a dollar-based true-up at the annual period Exports credited at the export rate; net usage billed at retail
Best system sizing Sized near or slightly above annual consumption Sized to self-consumption, often with batteries
Battery value Modest, mainly backup and peak shifting High, because storing and using power on site beats exporting
Predictability Simple, easy to model on a bill Depends on time-of-use exports and utility rate schedules
Paperwork and setup Standard interconnection, bidirectional meter Standard interconnection, plus time-of-use metering in many cases
Fit for homes with rising usage Good, credits offset growing load Weaker, since surplus exports earn less

Credit Value: Which Option Pays More Per Kilowatt-Hour?

Winner: Traditional net metering. Under the older structure, each exported kilowatt-hour is credited close to the full retail rate, so a panel that produces 10,000 kWh a year can offset roughly that much of your household use. Under export-based billing, the same kilowatt-hour is credited at a lower rate, and that rate can fall further during midday hours when solar output is highest across the grid. Owners often report that the gap feels largest in spring and fall, when production is strong and household load is light.

Surplus Exports and Monthly Rollover

Winner: Traditional net metering, for most homes. Excess credits generally carry forward month to month, and any remaining balance at the end of the annual period is settled, usually at a rate set by the utility. Export-based billing treats each hour’s surplus as a sale, which can be useful for a home that exports heavily but offers less protection if you produce far more than you use. Read your utility’s tariff language on rollover carefully, since the annual true-up terms are where most surprises show up.

System Sizing and Oversizing

Winner: Depends on your roof and goals. Under traditional net metering, sizing a system at or slightly above your annual kilowatt-hour use is the common target. Oversizing beyond that adds credits you may never fully use, and some utilities cap system size for net-metered interconnection. Under export-based billing, the logic reverses: a homeowner who can use most solar power on site, especially with a battery, often gains more from a moderately sized array than from one built to export.

Battery Storage and Self-Consumption

Winner: Export-based billing. When credits for exports are low, every kilowatt-hour you use directly from your panels or a battery is worth more than one you send to the grid. A battery lets you shift evening use into the afternoon, which tends to pay better under time-varying export rates. Traditional net metering still benefits from storage, mainly for backup during outages and for smoothing peaks, but the financial pull toward storage is weaker. For more on how grid-tied systems behave during outages, see How Grid-Tied Solar Works: Net Metering, Interconnection and Outages.

Predictability and Bill Modeling

Winner: Traditional net metering. A one-for-one credit is easy to model with a spreadsheet and a year of bills. Export-based billing requires you to know your utility’s hourly export rates, your usage pattern by time of day, and any seasonal schedule changes. Homeowners who like clear, simple numbers will find the older structure easier to plan around. For a real example of how the figures appear on a statement, Solar Net Metering Bill Example PDF: How to Read Yours Step by Step walks through a sample line by line.

Eligibility, Paperwork and Interconnection

Winner: Tie, with a note. Both options require an interconnection application, a utility-approved installer or licensed electrician, and an inspection before the system is energized. Both generally need a bidirectional meter. Some utilities add time-of-use metering for export-based customers, which may mean a meter change. Check your utility’s current application forms, since program details change, and confirm which tariff you are placed on before installation.

Which Should You Choose?

  • Choose traditional net metering if your system is sized near your annual use and you want simple, one-for-one credits.
  • Choose traditional net metering if you expect your household load to grow, for example from an EV or a heat pump.
  • Choose export-based billing if you plan to add a battery and use most of your solar power on site.
  • Choose export-based billing if your roof supports a larger array and you can time your use to midday production.
  • Choose traditional net metering if you want the most predictable bill and dislike tracking hourly rates.
  • Get a second opinion from a licensed installer or energy advisor before committing, especially on battery sizing and tariff choice.

If you are still deciding how to combine panels, storage and metering, Is Net Metering Worth It? What Home Solar Owners Should Know offers a broader financial frame, and Net Metering Solar Program: How It Works and How to Get Credited covers the enrollment side.

Both options use the same core hardware: panels, an inverter, a monitoring system and a bidirectional meter. The choice affects how much you invest in storage and monitoring. Here are product types to research, matched to each approach.

Product picks:

  • Enphase IQ8 Microinverter (for traditional net metering systems that favor module-level monitoring) View on Amazon
  • Tesla Powerwall 3 (home battery suited to export-based billing and self-consumption) View on Amazon
  • Emporia Vue 3 Energy Monitor (circuit-level monitor to track import and export) View on Amazon

FAQ

Does Illinois still offer traditional net metering for new systems?

Program rules change, and eligibility can depend on system size, utility territory and the date your application is submitted. Check with your utility and the Illinois Commerce Commission for the current tariff before you sign a contract.

Will a battery make export-based billing worth it?

Often yes, because storing solar power for evening use avoids the lower export credit. Whether it pays off depends on your battery cost, usage pattern and the utility’s hourly rates. A licensed installer can model your specific case.

What happens to unused credits at the end of the year?

Under most net-metering tariffs, leftover credits are settled at the end of the annual period at a rate set in the utility’s tariff. Read the true-up language in your agreement, since it varies.

Can I change my system size after installation?

Adding panels usually requires a new interconnection review, and the utility may apply different tariff rules to the expanded system. Discuss expansion plans with your installer and utility before buying equipment.

Should I talk to a professional before choosing a program?

Yes. Program rules, tax treatment and equipment warranties all affect the outcome, and small errors in sizing or tariff selection can be costly to correct. A licensed electrician, solar installer or energy advisor can review your roof, usage history and utility bills.

Conclusion

For most homeowners sized to their annual use, traditional net metering offers the simpler and more generous credit. Homes planning a battery, or those that can use most of their solar power on site, may do better under export-based billing. Start by pulling twelve months of usage data, estimating your annual production, and asking your utility which tariff applies to your address. Then compare the two options against your own numbers before you commit, and confirm the details with a licensed professional.

Ethan Brooks

About Ethan Brooks

Ethan Brooks is part of our editorial team and reviews and edits our home solar guides, checking product details against manufacturer specifications and owner feedback.