What type of oil is commonly used in oil heat systems?

The correct answer is No. 2 Heating Oil because it is the most commonly used type of oil in residential and commercial oil heating systems. No. 2 Heating Oil is a middle distillate fuel that provides an optimal balance between energy content and performance in burners commonly employed in heating applications. This fuel has a higher viscosity and a specific flash point, making it suitable for efficient combustion within the oil heating systems found in homes and businesses.

While No. 1 Heating Oil, kerosene, and diesel fuel can be used in some applications, they are not as prevalent as No. 2 Heating Oil for standard heating purposes. No. 1 Heating Oil is often more costly and better suited for extremely cold temperatures due to its lower viscosity. Kerosene, while similar in properties, is generally used in smaller space heaters and can be more expensive than heating oils. Diesel fuel can sometimes be used in place of heating oil but is not as suited for residential heating systems due to its different combustion characteristics and higher sulfur content (in the past) compared to No. 2 Heating Oil.