Kerosene vs Propane Heater Calculator
| $/MMBTU gap (P = propane wins) | propane $2.20 | $2.60 | $3.00 | $3.40 |
|---|---|---|---|---|
| $3.50 | P by $1.8 | K by $2.5 | K by $6.9 | K by $11.3 |
| $4.00 | P by $5.5 | P by $1.2 | K by $3.2 | K by $7.6 |
| $4.50 | P by $9.2 | P by $4.9 | P by $0.5 | K by $3.9 |
| $5.00 | P by $12.9 | P by $8.6 | P by $4.2 | K by $0.2 |
Enter what kerosene and propane cost per gallon at your pumps, the heater size in BTU, and how many evenings it runs. The calculator prices each fuel per hour of flame and per million BTU, shows the season gap, and computes the propane price at which the two tie.
The framing beyond the math: propane wins most price pairs because it carries more heat per dollar at typical pump prices - but kerosene keeps advantages the calculator cannot see. Kerosene stores for years without tanks exchanging, works from a simple fill spout, and every unvented model of either fuel shares the same two rules: ventilation and a CO alarm.
How to use
- Pump prices in dollars per gallon - kerosene typically runs $4-5 at the pump, propane exchange or refill $2-3.
- Heater size: convection kerosene units run 10,000-23,000 BTU; radiant propane cabinets 4,000-18,000.
- Hours per evening and days per season - a cold-region season of evening use is 100-150 days.
- Read the parity line: if your propane price is above the parity number, kerosene is the cheaper fuel for you.
Frequently asked questions
Is a kerosene heater cheaper to run than propane?
Usually not: kerosene carries 135,000 BTU per gallon against propane's 91,333, but kerosene's pump price is typically 60-80 percent higher, so per million BTU propane usually wins by 10-30 percent. At $4.50 kerosene against $2.80 propane the gap is about $3 per MMBTU - the calculator prices your actual pump pair.
How much does a kerosene heater cost per hour?
Divide the burner by 135,000 and multiply by the price: a 10,000 BTU unit at $4.50 is about 33 cents an hour, roughly $13 per 40-hour month. The same size propane unit at $2.80 runs about 31 cents - close enough that local prices, not the fuels, decide.
Which kerosene should I buy - is 1-K worth it?
Yes, always 1-K for indoor heaters: it is the low-sulfur grade that keeps the flame clean and the odor down. Red-dyed 2-K is for outside equipment; burned indoors it soots and stinks. Even 1-K leaves a faint smell that some people never notice and others cannot live with - which is the real reason kerosene heaters are a basement-and-garage tool for most families.
Do kerosene and propane heaters need ventilation?
Both, always: unvented fuel burners consume oxygen and emit water vapor and combustion byproducts, so crack a window and run a CO alarm in the room regardless of fuel. Venting requirements are the reason vented units exist at all - and why neither fuel is a whole-house answer.
Which fuel stores better for emergencies?
Kerosene, clearly: 1-K keeps 5-10 years in a sealed blue can without degrading, while propane is effectively immortal in the tank but you are storing metal cylinders or filling a larger tank. For a prepper shelf, kerosene plus a wick heater is the lower-maintenance pairing; for barbecue-adjacent convenience, propane is already in the garage.