Types of Heating Oil in the UK: A Clear Overview

Heating oil remains a vital energy source for many households and businesses in the UK, especially in rural areas where mains gas supply is unavailable. Delivered in bulk and stored on-site, heating oil powers oil-fired boilers and heaters that provide warmth and hot water. While heating oil might sound like a single product, it comes in different types with varying characteristics, uses, and legal regulations. This article explores the main types of heating oil used in the UK to help you understand their differences and applications.
What Is Heating Oil?
Heating oil is a refined petroleum product specifically designed for use in heating systems. It is similar to diesel but refined to different standards to ensure efficient and clean combustion. Heating oil is typically delivered in bulk and stored in tanks before being burned in oil-fired boilers or heaters.
Main Types of Heating Oil in the UK
In the UK, two primary types of heating oil are commonly used: Kerosene (28-second oil) and Gas Oil (35-second oil or red diesel). These differ in viscosity, taxation, application, and environmental impact.
1. Kerosene (28-Second Oil)
Kerosene, also known as 28-second oil, refers to the time it takes to flow through a test nozzle at 20°C — approximately 28 seconds. This oil is the standard for domestic heating.
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Usage: It is primarily used in homes to fuel oil-fired boilers and heaters.
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Benefits: Kerosene burns relatively cleanly, producing less soot and particulate matter, which helps maintain boiler efficiency and reduces maintenance.
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Cost: It is usually more expensive than gas oil because it carries a higher fuel duty.
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Environmental Impact: Though still a fossil fuel, kerosene produces fewer harmful emissions compared to heavier oils, making it a cleaner choice for residential heating.
2. Gas Oil (35-Second Oil or Red Diesel)
Gas oil, commonly called red diesel due to the red dye added for taxation purposes, has a thicker consistency and higher viscosity, taking around 35 seconds to flow in the standard test.
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Usage: This oil is mainly used in commercial, agricultural, and industrial heating systems, as well as some vehicles and machinery.
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Benefits: It is cheaper than kerosene because of its lower tax rate.
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Cost: The lower price makes it economical, but it is legally prohibited for domestic heating.
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Environmental Impact: Gas oil tends to produce more soot and particulate emissions, increasing pollution and potentially raising maintenance costs.
Emerging Option: Bioheating Oil
Bioheating oil is a growing alternative that blends traditional heating oil with renewable biofuels derived from vegetable oils or animal fats.
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Advantages: It reduces carbon emissions and can often be used in existing oil boilers without modification.
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Availability: Many UK suppliers now offer biofuel blends containing up to 30% renewable content.
Safety and Regulations
In the UK, kerosene is the only heating oil approved for most domestic heating applications. Gas oil is restricted to commercial and agricultural use due to tax laws. Proper storage in certified tanks and regular boiler servicing are essential for safety and efficiency.
Conclusion
For UK households, kerosene remains the standard heating oil due to its cleaner burning qualities and legal acceptance. Gas oil, while less expensive, is primarily reserved for commercial and agricultural purposes. Bioheating oil offers a promising environmentally friendly alternative that supports carbon reduction efforts. Understanding the differences between these heating oils helps consumers make informed decisions based on cost, efficiency, and environmental considerations.