How a gas supply offer works, in plain words.

Two halves of a bill

A gas bill has two kinds of charges. Delivery (the customer charge, distribution or transportation, riders) pays the utility for its pipes and meters, and you pay it whoever sells you the gas. Supply (the gas itself: "gas cost", "gas supply", "commodity") is the part a supplier's offer replaces. So an offer is compared with the supply part only, never with the whole bill. Source: PUCO supplier worksheet

The default price

If you never choose a supplier, the utility supplies the gas at its own default price. Its name differs from place to place ("price to compare", "gas cost recovery", a "standard" offer and others), and it can change every month. It is the number an offer has to beat. If you already buy from a supplier, the supply line on your bill is that supplier's price, not the default. The Bill Reader finds the supply price per therm on any bill.

Units

The meter measures volume: cubic feet, usually shown in hundreds (Ccf) or thousands (Mcf). Prices compare fairly only as heat, in therms (100,000 Btu). The bill's heat factor turns one into the other: at the 2025 U.S. average, 1 Ccf is 1.037 therms and 1 Mcf is 10.37 therms. A Dth (or MMBtu) is 10 therms. Source: EIA unit FAQ Convert units.

Fixed, intro and variable prices

Fixed: one price for the whole term. You know the supply price; you do not know whether the default will end up above or below it. Intro: one price for the first months, then another. If the offer does not fix the second price, nobody can compare it honestly: test it at a few prices. Variable: the price can change every month, so any comparison holds only while today's price holds.

Fees and rewards

A monthly fee is part of the price. Divided by your use it becomes cents per therm, and for a small home it can be most of an offer's cost. A sign-up fee is paid once. A sign-up reward (a gift card or a bill credit) is also paid once, while a higher price is paid every month. The Offer Check counts all of them in the first 12 months.

Leaving early and the end of a term

Many fixed offers charge a fee to leave before the term ends: a flat amount, or an amount for each month left. And every term ends: the contract says whether you roll onto a variable price, renew at a new price, or go back to the default. Put the end date in your calendar; the Offer Check makes a calendar file with a reminder 30 days before.

Questions to ask a supplier

Ohio's utility commission publishes a worksheet of questions for anyone comparing natural gas suppliers. Put your own state's commission in place of Ohio's and they work in any state where you can choose a gas supplier:

• Are you licensed (certified) by your state's utility commission? Check the answer on the commission's own list of suppliers.
• What is the price per Ccf or Mcf (or per therm)?
• Is the price fixed, or does it change? If it changes, how?
• Does the price depend on how much or when I use gas?
• Is there a switching fee? Is there a fee if I cancel early?
• Is there a customer incentive for signing up?
• Are there any special add-on services?
• How long will the rate stay in effect, and what happens when the contract expires?
• Will I get one bill or two, and who sends it? Is there a budget plan?
• Are there built-in price increases or decreases?

The same worksheet says to ask for the supplier's supply price and compare it to your current average cost of supply, to read the whole contract, and to give out your account number only when you are ready to sign up. Source: PUCO supplier worksheet

Some state commissions publish their own charts of offers or a bill calculator for their utilities, for example the District of Columbia's. Therm & Term lists no offers; it does the arithmetic on the one in your hand.