Can You Mix Kerosene and Home Heating Oil Safely?

Yes, you can mix kerosene and home heating oil, as they are both distillate fuels, but it is essential to check local regulations and manufacturer guidelines to ensure compatibility and proper performance in your heating system.

Homeowners with oil heating systems often wonder if they can mix kerosene with heating oil. While possible in small amounts, it’s not generally recommended due to differences in flashpoints and additives. Here’s what you need to know before combining these fuels.

Create an image of a fuel canister with a blend of kerosene and heating oil, set against a backdrop of a cozy home.

Key Differences Between Kerosene and Heating Oil

Though similar, kerosene and home heating oil have important distinctions:

Property Kerosene Heating Oil (#2 Fuel Oil)
Flashpoint ~100°F ~140°F
Refinement More refined Less refined
Cold Weather Performance Resists gelling Can gel in extreme cold
Cost More expensive More affordable

Why Flashpoint Matters

The lower flashpoint of kerosene means it vaporizes and ignites at lower temperatures than heating oil. This affects both safety and burner performance. According to Smart Touch Energy, this difference can lead to unpredictable combustion when mixed.

Create an image of a harmonious blend of different elements, symbolizing the concept of mixing in various contexts.

When Mixing Might Be Acceptable

In very small proportions (under 3% of total volume), mixing is unlikely to cause issues:

  • 7.5 gallons kerosene in 275 gallon tank (2.7% mix) is generally safe
  • Some technicians recommend winter blends with up to 30% kerosene for outdoor tanks
  • Many furnaces can burn either fuel separately without modification

As noted in our guide on what to do if heating oil freezes, kerosene’s anti-gel properties make it useful in cold climates.

Potential Risks of Mixing

Safety Concerns

Combining these fuels can:

  • Increase fire risk due to lower combined flashpoint
  • Produce more toxic fumes
  • Trigger carbon monoxide alarms
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Equipment Issues

Long-term mixing may cause:

  • Uneven heat output
  • Increased burner wear
  • Nozzle clogging from additive interactions

Professional Recommendations

HVAC technicians advise:

  1. Check your furnace manual for approved fuels
  2. Never mix more than 10% kerosene unless specified
  3. Consider separate use rather than mixing – burn one then switch
  4. For outdoor tanks, use pre-blended winter fuel instead of DIY mixes

Our article on common oil boiler issues explains how fuel quality affects system performance.

Alternative Uses for Leftover Kerosene

Instead of mixing, consider:

  • Using in kerosene heaters (with proper ventilation)
  • Cleaning parts (though wear gloves as noted by users)
  • Emergency lighting (in approved lamps)
  • Donating to someone with kerosene appliances

According to U.S. Department of Energy, kerosene works best in appliances specifically designed for it.

Final Considerations

While small, occasional mixes are unlikely to cause immediate problems, consistent mixing isn’t recommended. The safest approach is to use each fuel as intended in properly configured systems. For those considering fuel alternatives, our comparison of propane vs kerosene heaters provides additional options.

Joye
Joye

I am a mechanical engineer and love doing research on different home and outdoor heating options. When I am not working, I love spending time with my family and friends. I also enjoy blogging about my findings and helping others to find the best heating options for their needs.