#2 heating oil and diesel fuel are very similar petroleum products that are often mistaken for one another. While they share many of the same physical and chemical characteristics, there are some key differences between the two fuels that consumers should be aware of.
What is #2 Heating Oil?
#2 heating oil, also known as home heating oil, is a liquid petroleum product used to heat homes and businesses. It is a mid-weight distillate fuel oil that is typically comprised of longer hydrocarbon chains with between 10 and 20 carbon atoms per molecule.
#2 heating oil has a boiling point between 500-680°F and is less viscous and thinner compared to heavier fuel oils like #6 oil. It produces fewer emissions when burned compared to lighter fuels like kerosene or gasoline.
The #2 designation refers to its category under the American Society for Testing and Materials (ASTM) fuel grading system. It is also categorized as a Group II distillate fuel oil alongside diesel fuel. Other common names for #2 heating oil include:
- Fuel oil
- ASTM 2 fuel
- ASTM D396 No. 2 fuel oil
- Heating oil, burner oil
#2 heating oil is commonly used in the following applications:
- Oil burners in residential and commercial furnaces
- Boilers
- Oil-fired water heaters
It accounts for about 20% of all residential energy needs in the United States. Most oil heating systems are in the Northeast, where winters are coldest.
What is Diesel Fuel?
Like #2 heating oil, diesel fuel is another mid-weight petroleum distillate classified as a Group II fuel oil. Some key facts about diesel include:
- It is composed of long hydrocarbon chains with between 10-15 carbon atoms per molecule.
- Typical boiling point is 350-650°F.
- It has a lower viscosity compared to heavier fuels.
- Cetane rating of 40-55.
- Comes in grades 1-D, 2-D, and 4-D.
Diesel fuel is predominantly used to power diesel engines in vehicles and generators. Common applications include:
- On-road diesel vehicles like trucks, buses, and cars.
- Locomotives
- Marine vessels
- Construction equipment
- Agricultural vehicles
- Stationary generators.
Diesel accounts for about 20% of fuel sales in the United States annually.
Key Differences Between #2 Heating Oil and Diesel Fuel
While #2 heating oil and diesel fuel share many similarities, there are some key differences between the two:
1. Intended Use
The main difference is their intended use. #2 heating oil is intended for home and commercial heating applications like furnaces and boilers. Diesel fuel is made for powering diesel engines in vehicles and equipment.
2. Chemical Additives
Diesel contains additional chemical additives and up to 5% biodiesel. These additives help improve combustion, lubricity, and emissions in diesel engines. Heating oil does not contain these extra additives.
3. Taxation
In the United States, diesel fuel is taxed at a higher rate at the pump compared to heating oil. Heating oil is dyed red to indicate it is untaxed for legal use in stationary heating equipment only.
4. Storage Life
Diesel fuel often has additional stabilizers to prolong its storage life in vehicle tanks. Heating oil does not contain these stabilizers, so its storage life is generally less than diesel.
5. Performance
While their performance is fairly equal for home heating, diesel’s additives give it an edge over heating oil in vehicle diesel engines. Using untreated heating oil can lead to accelerated wear in diesel engines.
Can You Use #2 Heating Oil in Diesel Vehicles?
While not recommended, you can burn #2 heating oil in a diesel vehicle engine in an emergency if diesel is unavailable. However, there are some downsides to be aware of:
- May cause accelerated engine wear over time without additives.
- Heating oil lacks cetane improvers for optimal combustion.
- Risk of fuel filter clogging without anti-gelling agents.
- Legal risks associated with using untaxed red-dyed heating oil on roads.
Overall, it’s best to use diesel-formulated fuels in diesel vehicles when possible. Pre-treating heating oil with cetane boosters and other additives can help offset some of the downsides if diesel is not available.
Can You Use Diesel Fuel in Home Heating Systems?
You can safely use diesel fuel as an emergency backup option in oil-fired heating systems. However, there are some drawbacks:
- Higher cost – diesel fuel is taxed much higher than heating oil.
- Diesel additives are not needed for home heating performance.
- Risk of staining walls or giving off unpleasant odors from diesel exhaust smell.
Overall, it’s best to use #2 heating oil formulated specifically for home heating use. Diesel can be used in a pinch, but is not the ideal fuel for oil burners.
Key Specification Differences
Here is a table summarizing some of the key fuel specification differences between #2 heating oil and diesel fuel:
| Specification | #2 Heating Oil | Diesel Fuel |
|---|---|---|
| Intended Use | Residential/commercial heating | Diesel engines |
| Cetane Number | 40-50 | 40-55 |
| Chemical Additives | None | Detergents, cetane improvers, stabilizers |
| Taxation | No road tax, dyed red | State/federal road taxes |
| Typical Uses | Furnaces, boilers, heaters | Vehicles, engines, generators |
Finding the Right Fuel for Your Needs
When purchasing fuel, be sure to choose the product designed specifically for your intended application. While diesel engines can burn heating oil, and heating systems can burn diesel fuel, each product is specially formulated for optimal performance in its intended application.
Always consult your equipment manufacturer for fuel recommendations. Improper fuel usage can lead to decreased performance and costly repairs down the road.
Both heating oil and diesel fuel are widely available from fuel suppliers and delivery companies. Heating oil is sold per gallon and delivered by truck for easy home filling. Diesel is available at any gas station pump in the United States.
With rising fuel prices, many consumers are looking to save on heating and transportation fuel costs. While diesel and heating oil are very similar products, understanding the key differences allows you to choose the right fuel for your specific needs.
Conclusion
In summary, while #2 heating oil and diesel fuel share many physical and performance characteristics, they differ primarily in their intended use cases and fuel formulations. Diesel contains additives beneficial for engines, while heating oil is specially refined for home and commercial heating with oil burners and furnaces. Both can be used interchangeably in a pinch, but each is specially designed to excel in their target applications.