Can You Use Diesel in a Fuel Oil Furnace?

A member of the Marstellar Oil & Concrete team pumping fuel.

Many Pennsylvania households use furnaces to keep warm during colder months. However, you may reach a time when you start running out of heating oil, and your next oil delivery is only in a few days.

If you run out of heating oil, you can use diesel as a short-term solution until you can get more. Learn more about using diesel as a replacement for oil in your furnace below.

Can You Put Diesel in Your Oil Tank?

Yes, you can. While waiting for your oil supply delivery, you can substitute diesel for heating oil. Diesel and heating oil can also be mixed if you’re running low on oil and are worried about running out. Both are midweight distillations of petroleum. Because of this, they burn similarly and can have the same heating effect.

While diesel makes an effective stop-gap when you’re short on heating oil, it should only be used as a short-term solution. Furnaces are made to run on specific oil and are built to accommodate the burning heat, viscosity and other characteristics of heating oil.

Diesel burns slightly hotter than heating oil, which can be beneficial for extremely cold nights. However, over time, this additional heat can wear down components at a slightly quicker rate, shortening the life span of your furnace.

In addition, diesel is more expensive than heating oil. Most oil tanks are around 275 gallons and hold approximately 225 gallons of fuel, so it’ll take multiple trips to a gas station to get enough diesel to fill up your tank. Using diesel for your furnace will be significantly more expensive than heating oil.

Kerosene is another alternative to heating oil. Like diesel, it should only be used as a short-term solution, as it burns hotter than oil. It also has a lower flashpoint than heating oil, making it easier to catch fire. Always follow the proper safety procedures to prevent accidents.

Please note that you should never use gasoline. It emits flammable fumes and may result in a fire or explosion.

Is Running out of Oil Bad for a Furnace?

The main concern when running out of oil is that your furnace will automatically shut down. Most furnaces have an emergency shutoff that switches off the furnace when oil levels get low. It’s a safety feature that helps protect your furnace from continuing to work without oil, which can cause significant damage.

Running on low or no oil for a short time every so often may not damage your furnace. However, if your furnace runs without oil frequently or for a long time, it can damage the filter, oil pump and oil line. You may also have to bleed the oil line to remove any dirty oil, sediment and air that may cause further damage or blockages.

A technician will have to replace these parts, resulting in extra costs and further delays in getting your furnace working to keep you warm. Additionally, your pipes may freeze if your furnace is off for long enough, leading to blockages and other damage that can be costly to repair.

What to Do if You Run out of Heating Oil

When you notice your oil levels are dropping or your furnace automatically shuts off, remain calm. The first thing you should do is check the thermostat control and ensure your furnace is off. Doing this will ensure you and your home are safe while you continue investigating.

Next, you need to make sure you’re actually out of oil. You can do this by checking the float gauge. If the float moves freely, isn’t visible or sinks to the bottom of the tank you are low on oil or out completely. Once you’re sure you’re out of fuel, you can contact your local heating oil supplier to organize a refill of your tanker.

Can you put diesel in your oil tank? Yes, you can substitute diesel for heating oil while waiting for your oil supply delivery.

The Difference Between Heating Oil and Diesel

In the past, there might have been variations in BTUs, but heating oil and diesel fuel are essentially the same. The key difference lies in the dye: diesel fuel lacks dye and is taxed for on-road use. Heating oil is dyed red, making it unsuitable for on-road applications and exempt from on-road taxes. It’s safe to use diesel fuel in a heating oil system, but it costs roughly $1.00 extra per gallon due to on-road taxes. Diesel and heating oil have different prices due to the way they’re taxed. Heating oil is untaxed, as it’s considered an essential fuel, while diesel has a road tax levied on it. This makes buying diesel at the pumps and getting it delivered more expensive, as the base cost of diesel is higher.

However, only a few gas stations may offer heating oil at the pumps, which means heating oil has to be delivered to your house. This additional delivery cost slightly raises the cost of heating oil, but it’s still cheaper than getting diesel delivered.

In addition, the price of heating oil and diesel fluctuates depending on the price of crude oil and the season. As demand for heating increases during winter or cold weather approaches, heating oil costs rise. You can combat this increase by filling your tank a few months in advance.

How to Safely Add Diesel to Your Furnace

Once you’ve confirmed you’re out of heating oil, you need to make you safely add it to your furnace tank. You can start by finding a fuel container. Depending on how long you need to run the furnace before you get your heating oil, choose to get either 5 or 10 gallons of diesel. If you don’t have any at home, you may be able to buy containers at the gas station.

Ensure you use the correct yellow diesel containers to distinguish between the different fuels you have at home. Once you have the diesel, confirm your furnace is off. You should never fill up your oil tank while your furnace is running. Locate your oil tank’s fill pipe and pour in your desired amount of diesel. A good rule is about 5-10 gallons for a day.

Close your tank fill pipe and wait about 15-20 minutes. This will give the diesel time to settle and allow any sediments to sink back to the bottom. Giving everything time to settle ensures sediment stays out of your fuel pipes and reduces the risk of blockages. Then, restart your furnace. This may take a few tries, as the diesel may need time to bleed through the lines.

Get fast heating oil deliveries in Central PA with Marstellar Oil and Concrete.

Get Fast Heating Oil Deliveries in Central Pennsylvania With Marstellar Oil and Concrete

While you can use diesel or kerosene in an oil furnace in an emergency, they’re not ideal long-term solutions for keeping warm. At Marstellar Oil and Concrete, we provide same-day or next-day deliveries of low quantities of home heating oil, so you always have heat in the winter. Our easy-to-use online heating oil ordering process can save you time and money.

Order heating oil through our website or contact us today!

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