U.S. propane inventories hit 107.013 million barrels in mid-August, the highest level ever recorded, according to Energy Information Administration data reported by LP Gas magazine. That’s useful context if your propane dealer just mailed you a propane prebuy offer with a September deadline. A prebuy locks your winter price, which protects you from a spike. With record supply going into the season, a spike is a smaller risk than usual, and the lock has a downside the dealer letters rarely spell out.
A propane prebuy is a bet, not a discount
Most of what you’ll read about prebuying comes from dealers, and the pitch is the same everywhere: lock in now and save. The part that gets skipped is that a fixed lock cuts both ways. New Hampshire’s Department of Energy states it plainly on its pre-buy page: the contract is legally binding, the amount and price can’t be changed, and if market prices fall, you still pay the pre-buy rate. The dealer has already bought the fuel at that price and isn’t going to eat the loss for you.
The real decision is how much you’re willing to pay for a known bill instead of a cheaper expected one. That’s a reasonable trade for a lot of households. It just shouldn’t be sold as free money.
What the average propane household spends
EIA’s winter fuels outlook last October expected the average propane-heated home to use 493 gallons over the 2025-26 winter at $2.46 a gallon, about $1,210 in total. About 5% of U.S. households heat mainly with propane, and for them a 20-cent swing per gallon is real money. By EIA’s April update, the propane estimate for that winter had risen to $1,286. Heating oil households had it worse: the April update put their winter bill at $1,749, 15% higher than the winter before.
Those numbers are national averages, and your own usage could be very different. The best guide is your own delivery history. Add up the gallons from last October through March and use that number for the math below.
The worked example: lock, cap, or neither
Say your household uses the EIA average of 493 gallons and your dealer offers a fixed lock at $2.46, the same price EIA used for last winter. Your contracted cost is $1,212.78.
If the winter’s market price ends up 10% higher, around $2.71, you’d have paid $1,334.06 without the contract. The lock saves you $121.28. If the market price ends up 10% lower, around $2.21, you’d have paid $1,091.50 without it, and the lock costs you $121.28. Same size win, same size loss.
A price cap changes that. Instead of a fixed price, you get a ceiling, and you pay the lower market price if it drops below it. New Hampshire’s page gives a typical cost of either a premium of about 20 cents a gallon or a flat fee of $50 or $100. With a $100 fee on 493 gallons, the cap pays for itself only if prices fall by about 20.3 cents a gallon. In the 10% drop scenario, you’d pay $1,091.50 plus the $100 fee, which is $21.28 better than the plain lock. If prices rise, the cap gets you the same protection as the lock but costs $100 more.
| Scenario (493 gallons) | No contract | Fixed lock at $2.46 | Cap at $2.46 + $100 fee |
|---|---|---|---|
| Prices fall 10% | $1,091.50 | $1,212.78 | $1,191.50 |
| Prices rise 10% | $1,334.06 | $1,212.78 | $1,312.78 |
The fee works like an insurance premium. The more gallons it’s spread over, the smaller the drop it needs to pay off: New Hampshire’s own example shows a $100 fee on 1,000 gallons breaking even at a 10-cent drop.
The fine print that costs more than the price
The per-gallon number is the only thing most people compare, and it’s often not where the money goes. Wisconsin’s consumer protection agency notes that propane prices aren’t regulated under state law, which means the contract decides everything, and it lists a set of fees worth asking about in writing: trip charges, after-hours and weekend delivery, partial fills, and tank inspections. A small-volume customer who needs one emergency delivery can lose the prebuy savings on that alone.
Two other terms deserve a slow read. The first is what happens to gallons you don’t use. New Hampshire says a common approach is to credit the leftover amount toward off-season purchases at the current price, not the price you locked. If you prebuy 600 gallons and burn 450 during a mild winter, those extra 150 gallons may not be worth what you paid for them. The second is what happens when you run out. Wisconsin’s guide warns that once prepaid gallons are used up, you’ll typically pay market price for the rest, so underbuying doesn’t fully protect you either. I’d prebuy no more than about 80% of your lowest recent winter’s usage and let the rest float.
A budget plan smooths the bill without the bet
If your real problem is that a $400 delivery in January wrecks your checking account, you don’t need a price lock. You need a payment plan. Many dealers offer budget billing that spreads the estimated season’s cost across 10 or 12 months. Using the same 493 gallons at $2.46, that’s $101.06 a month over 12 months or $121.28 over 10. Wisconsin notes that these payments can be adjusted mid-winter if your usage or prices change, so a cold January can still raise your payment.
You can also run your own version. Set aside about $101 a month in a separate savings account starting now, and you’ll have most of a season’s propane covered by March without signing anything. The same countdown approach in the post on starting a sinking fund in September works for heating fuel too.
How to decide before the deadline
There’s one more timing problem with September decisions. EIA’s weekly survey of residential propane and heating oil prices only runs during the heating season, October through March, so the government’s most useful consumer price data isn’t being collected while you’re deciding. Call two or three dealers and ask each for a fixed price, a capped price with the fee, and the current market price for the same number of gallons. That’s the only comparison that tells you anything. While you have them on the phone, ask for your own delivery history from last season if you don’t have the receipts. Dealers keep it, and it’s a far better basis for sizing a contract than a national average or a guess about how cold January will be.
If you own your tank, you can shop around freely. If you rent it, Wisconsin points out that most dealers won’t fill another company’s tank, so your bargaining power is weaker and the fee list matters more.
My rule of thumb: take a propane prebuy only if you can afford to pay for it upfront without touching emergency savings, and only for gallons you’re nearly certain to burn. If falling prices would really sting, pay for the cap and divide its fee by your gallons so you know exactly what drop you’re betting on. If neither option fits, a budget plan or a monthly transfer to savings does the main job (no surprise $400 bill in January) without asking you to predict the market.
Sources: U.S. Energy Information Administration, Winter Fuels Outlook 2025-26; New Hampshire Department of Energy, pre-buy contracts for heating fuels; Wisconsin DATCP, propane consumer tips; LP Gas magazine, August 2026 inventory report
