In states with electricity choice, you can buy the electricity itself from a company other than your utility. The utility still delivers it and still sends most customers the bill. Offers arrive by mail, phone and at the door. The only way to know whether one saves money is to compare it with your utility’s default price, called the price to compare.
What You Are Actually Comparing
A bill in a choice state has two main parts:
| Part | Who sets the price | Changes if you switch? |
|---|---|---|
| Supply (generation) | Your utility’s default price, or your supplier’s contract price | Yes |
| Delivery (transmission and distribution) | Your utility, under rates set by regulators | No |
Illinois’ state shopping site describes the utility’s default supply as provided “without any mark-up or profit.” Delivery charges are the same whoever supplies your power.
Your price to compare is on your bill or your state’s shopping website. In Illinois, ComEd’s price to compare for October 2026 to May 2027 is 10.103¢ per kWh. See our Illinois guide and, for Ohio, our Ohio guide.
The Formula
Effective price = (supplier rate × monthly kWh + monthly fee) ÷ monthly kWh
Then compare the effective price with the price to compare for the same months.
Break-even usage = monthly fee ÷ (price to compare − supplier rate)
Below the break-even usage, the fee outweighs the lower rate.
Worked Example
A hypothetical offer compared with ComEd’s 10.103¢ price to compare:
| Default supply | Supplier offer | |
|---|---|---|
| Rate | 10.103¢/kWh | 9.49¢/kWh, fixed 12 months |
| Monthly fee | None | $4.95 |
| Cost at 700 kWh | 700 × 10.103¢ = $70.72 | 700 × 9.49¢ + $4.95 = $71.38 |
| Effective price at 700 kWh | 10.103¢ | 10.20¢ |
| Cost at 1,000 kWh | $101.03 | $99.85 |
- Break-even: $4.95 ÷ (10.103¢ − 9.49¢) = about 808 kWh a month.
- At 700 kWh the offer costs $0.66 more a month. At 1,000 kWh it saves $1.18.
The offer is invented to show the method. The price to compare is real but changes. ComEd’s runs through May 2027.
Introductory Rates
Some offers start low and then change. Suppose a hypothetical offer charges 7.99¢ for 3 months, then a variable rate averaging 12.5¢ for the next 9 months, at 700 kWh a month:
- Supplier year: (3 × 700 × 7.99¢) + (9 × 700 × 12.5¢) = $955.29
- Default supply at 10.103¢ for 12 months: $848.65
The offer that looked 21% cheaper costs $106.64 more over the year. Always ask what the rate becomes after the introductory period, and how it is set.
Fixed, Variable and Unlimited Plans
Pennsylvania’s official shopping site, PAPowerSwitch, describes the trade-offs:
| Plan type | How it works | Watch for |
|---|---|---|
| Fixed | One all-inclusive per-kWh price for at least three billing cycles or the contract term, whichever is longer | May cost a little more; may carry cancellation fees; may roll to variable at the end |
| Variable | Price can change by hour, day or month under the contract terms | Hard to budget; can rise sharply in extreme weather |
| Unlimited (flat) | One monthly price for supply, not based on kWh | Ask about pricing tiers, usage limits and cancellation fees |
What Pennsylvania Requires Suppliers to Give You
Pennsylvania is a useful model of the disclosures to look for. Suppliers there must provide a one-page contract summary at enrollment that states:
- Whether the price is fixed or variable, and for variable rates, what it is based on and any ceilings.
- The supply price, including any introductory rate and how long it lasts.
- Prices at 500, 1,000 and 2,000 kWh if fees or usage tiers apply.
- That the supply price “may not always provide savings.”
- Contract length, cancellation fees, and what happens at the end of the contract.
- A 3-day right of rescission.
You also get two renewal notices, 45 to 60 days and 30 days before the contract ends. PAPowerSwitch warns that if you take no action, “a fixed rate may change to a monthly variable rate.” Switching back to the utility has no cost in Pennsylvania, though your supplier contract may have a cancellation fee.
Rules differ by state. Check your state’s shopping site for its version.
Municipal Aggregation
Some cities and towns buy supply for all residents who don’t opt out. These programs are not automatically cheaper. The Citizens Utility Board of Illinois reported that most municipal aggregation deals it reviewed in Ameren territory cost more than the utility’s price. Compare your program’s rate with the price to compare the same way.
Solar Owners
If you have net metering, switching supplier can change how your exports are credited. Ohio’s net metering rules, for example, let competitive supplier customers keep net metering, but suppliers “may compensate excess generation differently than utilities,” according to Solar United Neighbors. Ask any supplier, in writing, how it credits exported power before you sign. See our Ohio net metering article.
Checklist Before You Sign
- Find your current price to compare and the months it applies.
- Get the supplier’s rate, monthly fee, contract length and cancellation fee in writing.
- Calculate the effective price at your own usage, using last year’s bills.
- Ask what happens after any introductory period and at contract end.
- Note the rescission period and the renewal notice dates.
- Never give your account number to someone you did not contact. Your account number is how a supplier enrolls you.
Limitations
Rules, fees and protections differ by state. The detailed disclosure rules here are Pennsylvania’s. The offers in the examples are invented. Default prices change, usually every six or 12 months. This is general information, not financial advice.
Sources
- PAPowerSwitch (Pennsylvania PUC), “Understanding Contracts”
- PAPowerSwitch (Pennsylvania PUC), “Understanding Fixed, Variable & Unlimited”
- Plug In Illinois (Illinois Commerce Commission), “Understanding the Price to Compare”
- Citizens Utility Board, ComEd new price, September 28, 2026
- Solar United Neighbors, Net metering in Ohio
Frequently asked questions
What is the price to compare?
It is your utility's default price for electricity supply, the part of the bill a competitive supplier would replace. It does not include delivery charges, which you pay to the utility no matter who supplies your power.
How do I know if a supplier offer will save money?
Calculate the effective price: the supplier's rate times your monthly kWh, plus any monthly fee, divided by your kWh. Compare that with the price to compare for the same months, and check how long both prices last.
Is a fixed rate or a variable rate better?
A fixed rate stays the same for the contract term and is easier to budget, but may cost a little more and can carry cancellation fees. A variable rate can rise or fall with the market and often has no cancellation fee. Pennsylvania's PAPowerSwitch notes variable rates can rise sharply in extreme weather.
What happens when my supplier contract ends?
It depends on the contract and state rules. In Pennsylvania you get two renewal notices, and if you take no action a fixed rate may change to a monthly variable rate. You can usually return to your utility's default service.
