Heating Oil Basics → Kerosene vs Heating Oil
K-1 kerosene and #2 heating oil are closely related fuels — both are petroleum distillates used for home heating. But they're not interchangeable in every situation. The difference comes down to cold weather performance, cost, and where your tank sits.
This guide covers the practical differences so you can decide which fuel (or blend) makes sense for your home.
The single most important difference between these fuels is gel point — the temperature at which wax crystals form and clog fuel filters and lines.
| Property | #2 Heating Oil | K-1 Kerosene |
|---|---|---|
| Gel point | ~20°F (-7°C) | ~-40°F (-40°C) |
| BTU per gallon | 138,500 | 135,000 |
| Efficiency | 85% | 87% |
| Typical price premium | Base | +$0.50–$1.00/gal |
| Sulfur content | Higher | Very low |
| Soot production | Normal | Minimal |
#2 heating oil has slightly more energy per gallon (138,500 vs 135,000 BTU), but K-1 kerosene burns more efficiently (87% vs 85%) and produces less soot. In practice, the heat output per gallon is nearly identical.
Outdoor tanks. If your oil tank is outside — above ground or in an unheated shed — kerosene or a kerosene blend is essential in cold climates. An outdoor tank in Maine at 5°F with straight #2 oil will gel, and your furnace will shut down.
Extended cold snaps below 20°F. Even indoor tanks in poorly insulated basements can be at risk during prolonged cold. If your basement stays above 40°F, you're fine with straight oil. If it drops below 30°F, consider a blend.
Backup kerosene heaters. Portable kerosene space heaters require K-1 kerosene — never use #2 heating oil in them. The higher sulfur in oil produces dangerous fumes in unvented heaters.
Indoor tanks above 40°F. If your tank is in a heated basement, there's no reason to pay the kerosene premium. The fuel never gets cold enough to gel.
Cost-sensitive situations. At $0.50–$1.00 more per gallon, kerosene costs $137–$275 more to fill a 275-gallon tank. If you don't need the cold weather protection, that's money saved.
Most homeowners in cold climates don't use 100% kerosene — they use a blend. Mixing kerosene with heating oil lowers the effective gel point proportionally:
| Blend | Gel Point Protection | Best For |
|---|---|---|
| 100% Oil | ~20°F | Indoor tanks, mild winters |
| 80/20 Oil/Kerosene | ~8°F | Moderate cold (10–20°F) |
| 70/30 Oil/Kerosene | ~2°F | Cold weather (0–10°F) |
| 50/50 Oil/Kerosene | ~-10°F | Extreme cold (-10–0°F) |
| 100% Kerosene | ~-40°F | Outdoor tanks, sub-zero |
Many suppliers offer pre-blended fuel during winter months. You can also add kerosene to an existing tank of oil — the fuels mix freely.
Use our blend calculator to find the right ratio for your temperature and see the blended cost.
Kerosene typically costs $0.50–$1.00 more per gallon than heating oil from the same supplier. The premium reflects additional refining required to lower the gel point and reduce sulfur content.
For a 275-gallon fill:
| Fuel | Price/gal (example) | 275-gal fill | Savings vs kerosene |
|---|---|---|---|
| #2 Heating Oil | $4.50 | $1,238 | $206 |
| 80/20 Blend | $4.65 | $1,279 | $165 |
| 70/30 Blend | $4.73 | $1,300 | $144 |
| 50/50 Blend | $4.88 | $1,341 | $103 |
| 100% K-1 Kerosene | $5.25 | $1,444 | — |
The 80/20 blend hits the sweet spot for most homeowners — gel protection down to ~8°F at only $41 more than straight oil per fill.
Kerosene delivery works the same as heating oil — COD (cash on delivery) with typical minimums of 100–150 gallons. Most suppliers carry both fuels on the same truck.
Not all suppliers publish kerosene prices online. If you don't see a kerosene price listed, call and ask — many suppliers offer it but only quote by phone.
Compare K-1 kerosene prices from local suppliers →
Kerosene use is concentrated in northern New England, where outdoor tanks and extreme cold are common:
South of Massachusetts, kerosene demand drops significantly because winters are milder and outdoor tanks are less common.
Yes. K-1 kerosene is fully compatible with #2 heating oil furnaces and boilers. You can use it straight or blended with oil in any ratio. Many homeowners switch to a blend during cold months and back to straight oil when temperatures moderate.
No. Kerosene actually burns cleaner than #2 oil, producing less soot and leaving less residue on heat exchangers. Some technicians recommend an occasional kerosene fill to help clean the system.
No. Portable kerosene space heaters are designed for K-1 only. #2 oil has higher sulfur content and produces toxic fumes when burned in unvented heaters. Only use K-1 kerosene in appliances labeled for kerosene.
Signs of gelling: furnace cycles on but shuts down quickly, fuel filter appears cloudy or waxy, fuel won't flow through lines. If temperatures drop below 20°F and you have an outdoor tank with straight oil, gelling is likely. Call your supplier for a kerosene delivery to blend into the tank.
K-1 kerosene is lighter and more refined than diesel. Both are distillates, but diesel has a higher gel point (~15°F for winter blend) and higher sulfur. You can use K-1 kerosene as a diesel anti-gel additive, but don't use diesel as a kerosene substitute in heaters.
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