ComEd Default Supply vs. an ARES: How a Small Business Should Decide

Small commercial customers in northern Illinois face a recurring decision: keep buying the supply portion of your electricity from ComEd at its default rate, or contract with a licensed Alternative Retail Electric Supplier (ARES). The choice is often presented as a foregone conclusion — that switching always saves money — but that framing is wrong. This guide explains what each option actually means, what changes and what stays the same when you switch, and how a small business should decide by benchmarking against the price-to-compare.

Two parts of your bill: delivery and supply

The most important thing to understand before deciding is that your electricity bill has two distinct parts:

• Delivery — the cost of moving electricity over ComEd's poles and wires to your building, plus metering and related charges. This is regulated and always handled by ComEd.
• Supply — the cost of the electricity itself, the commodity. This is the only part you can choose to buy from someone other than the utility.

Illinois has a competitive supply market, so eligible commercial customers can either take default supply from the utility or contract with a licensed ARES for the supply portion. For a deeper walkthrough of how this works, see how Illinois commercial electricity choice works and the broader commercial electricity overview. (Note that a few Illinois communities with municipal electric utilities, such as Naperville and Springfield, have no retail choice at all; this decision applies where competitive supply is available.)

What staying on ComEd default supply means

If you do nothing, you remain on the utility's default supply service. The Illinois Power Agency (IPA) procures power on behalf of default-service customers, and the resulting rate becomes the price-to-compare — the benchmark against which every competitive offer should be measured. See Illinois Power Agency default service explained for how this procurement works.

Default supply has some distinct characteristics. The rate can change on the utility's schedule rather than being locked for a term, so it offers less price certainty but also no long-term commitment. There is no contract to sign, no early-termination language, and no supplier relationship to manage. For some small, steady loads, that simplicity is genuinely valuable — and sometimes the default rate is simply the better deal. The guide price-to-compare: when utility supply wins explores exactly when staying put is the right call.

What contracting with an ARES means

An ARES is a licensed competitive supplier that sells you the supply portion of your electricity under a contract you negotiate. Contracting with one can offer things default service does not:

• A fixed rate for a defined term, which provides budget certainty across the contract period.
• Alternative structures, such as index or blended products, for businesses that want to manage price risk differently. See fixed vs. index commercial electricity.
• Specific features, such as renewable content, that a business may want for its own reasons.

Contracting also brings obligations. You sign a contract with a term, notice window, and termination language; you take on a supplier relationship; and you must read the terms carefully, because the headline rate is not the whole story. For a fuller treatment of what changes financially, see the financial implications of switching from ComEd default service to an ARES.

What actually changes — and what does not

This is where many small businesses are misled. When you switch to an ARES, here is what changes and what stays exactly the same:

Changes:

• Who supplies the commodity portion of your electricity.
• The supply rate and its structure (fixed term, index, etc.).
• Whether you have a contract with terms and a notice window.

Does not change:

• Delivery. ComEd still delivers your power over the same lines.
• Reliability and outages. ComEd still maintains the system and restores service during outages, regardless of your supplier. Your supplier has nothing to do with whether your lights stay on.
• Your meter and, typically, your bill. In most cases ComEd continues to read your meter and send a single bill that includes both delivery and the supplier's charge.

Understanding this cleanly removes the two most common myths: that a competitive supplier makes your power "greener at the plug" or "more reliable." Neither is true — the electrons and the wires are the same. What you are choosing is a commodity price and contract terms.

How a small business should decide

The decision comes down to a disciplined comparison, not a sales pitch. A workable process:

1. Establish your price-to-compare. Know the utility default supply rate for your customer class, for the period you would actually be shopping. This is the benchmark. Time-sensitive values should be confirmed against current ComEd and IPA sources rather than taken from a supplier's marketing.
2. Collect real offers on matched terms. Ask suppliers to quote the same start date and volume so the comparison is genuine. Then compare offers apples-to-apples — not just the rate, but what is included and what passes through.
3. Read the contract, not just the number. Check the term, the notice and renewal window, pass-through clauses, and early-termination language. A low rate wrapped in an automatic renewal or a punitive exit clause may not be the bargain it appears.
4. Verify the supplier is licensed. Confirm the ARES is licensed with the Illinois Commerce Commission before signing.
5. Weigh non-price factors honestly. Budget certainty, contract simplicity, and specific features all have value. If a competitive offer does not beat the price-to-compare on the terms that matter to you, staying on default supply is a perfectly valid decision.

For a small business new to this, the single most important discipline is measuring every offer against the price-to-compare. That one benchmark converts a confusing sales conversation into a clear yes-or-no question.

The bottom line

Choosing between ComEd default supply and a licensed ARES is a choice about the supply portion of your bill only. Delivery, reliability, and outage response stay with ComEd no matter what. A competitive supplier can offer a fixed rate, alternative structures, or specific features — but only a real, apples-to-apples comparison against the price-to-compare reveals whether switching actually serves your business. Sometimes it does; sometimes staying put is smarter. The benchmark is how you know.

Sources

• Illinois Commerce Commission — Plug In Illinois: Electric Choice Basics
• Illinois Power Agency — Electricity Supply Rates
• ComEd — Supplier and Rate Information

Comparing supply options helps you decide from a position of choice; it does not promise any particular rate or savings.