You can burn used motor oil, transmission fluid, and other clean petroleum-based oils in a waste oil heater, ensuring they meet local regulations.
Waste oil heaters offer an eco-friendly and cost-effective way to repurpose used petroleum products while heating your facility. But knowing exactly what you can and can’t burn is critical for safety, efficiency, and equipment longevity.
Approved Fuels for Waste Oil Heaters
Most waste oil heaters can safely burn these common petroleum products:
- Used motor oil (crankcase oil from gasoline/diesel engines)
- Transmission fluid (automatic and manual)
- Hydraulic fluid (standard petroleum-based)
- Gear oil
- Diesel fuel
- #2 heating oil
- Synthetic oils (most types)
Many systems allow mixing these approved oils in any combination. For example, a built-in gas heater might offer similar flexibility with fuel types.
Special Considerations for Hydraulic Fluid
While most hydraulic oils burn well, some varieties require special handling:
| Hydraulic Oil Type | Burnability | Notes |
|---|---|---|
| Standard petroleum-based | Excellent | Burns similar to motor oil |
| High-temperature grades | Poor | Requires mixing with more volatile oils |
| Water-glycol based | Never | Can damage system and create safety hazards |
According to Clean Energy Heating Systems, water-containing hydraulic fluids should always be avoided as they can cause gelling in preheaters.
Substances You Should Never Burn
These materials can damage your heater or create dangerous conditions:
- Antifreeze/coolant
- Brake fluid
- Chlorinated solvents
- Paint thinner
- Gasoline
- Kerosene
- Water-containing fluids
- Any flammable liquids with flashpoints below 100°F
As noted in waste oil heater forums like WasteOilHeaterForum.com, improper fuels can lead to clogged filters, damaged pumps, and even explosions in extreme cases.
Optimizing Your Waste Oil Mixture
Viscosity Considerations
The ideal waste oil blend has a viscosity similar to #2 heating oil (about 5-7 cSt at 40°C). Too thick and it won’t atomize properly; too thin and it may not provide enough lubrication for pumps.
Pre-Treatment Recommendations
For best results:
- Let oil settle in storage tanks to allow water and contaminants to separate
- Filter through at least 10 micron filters before burning
- Pre-heat thicker oils to improve atomization
These steps are similar to maintenance practices for other heating systems like the best indoor propane space heaters.
Environmental and Efficiency Benefits
Properly burning waste oil:
- Reduces hazardous waste disposal costs
- Provides nearly free heat (just equipment and maintenance costs)
- Can save $3-$5 per gallon compared to conventional heating fuels
- Meets EPA standards for approved waste oil burners
When maintained properly, waste oil heaters can be as efficient as many conventional heating systems, with some models achieving combustion efficiencies over 85%.
