What Is the Right Heating Oil Tank for Your Home?

A heating oil tank has to do more than fit in your garden. It needs to hold enough fuel for your household and suit your heating system, and it has to meet the installation requirements that apply to your property.

Whether you are replacing an ageing tank or buying one for the first time, here is what to consider.

Bunded or single skin?

The first decision is how your oil will be contained.

A single skin oil tank has one wall holding the fuel. It usually costs less upfront, but has no built-in secondary containment if that wall leaks.

A bunded oil tank has an inner tank surrounded by a protective outer enclosure. This provides secondary containment if the inner tank leaks. A bund should hold at least 110% of the inner tank's capacity.

A bunded tank gives you more protection against oil escaping into the ground around it. However, whether bunding is legally required depends on your location and installation circumstances. Requirements differ across the UK, so a single skin replacement is not automatically acceptable just because you already have one. An installer can confirm what applies at your property.

Plastic or steel?

Both materials are used for home heating oil tanks, and either can suit a domestic installation.

Plastic tanks are generally lighter and easier to handle during installation. They do not rust and are available in different shapes, including slimline designs for restricted spaces. However, they still need correct support and regular checks for damage or deterioration.

Steel tanks are a sturdier option, but you will need to think about their weight and how you get them into position. Their protective coating and condition should also form part of ongoing maintenance.

Compare the individual tank's dimensions, warranty, and installation instructions alongside the material. OFTEC recommends tanks manufactured to OFS T100 for plastic or OFS T200 for steel.

What size heating oil tank do you need?

Your ideal heating oil tank size depends on how much oil you use and how frequently you want deliveries.

Start with your previous 12 months of delivery records, allowing for any difference in the tank level at the beginning and end of that period. Consider:

• Whether oil supplies heating, hot water and cooking.
• Your home's insulation and heating habits.
• Higher consumption during winter.
• Your preferred delivery quantity and a reserve between orders.

For example, using 2,000 litres annually does not automatically mean you need a 2,000-litre tank. A smaller tank with more frequent deliveries may suit your circumstances. A bigger tank gives you more flexibility over when you order, if you have the space and the budget.

Check whether the advertised capacity is nominal or usable. Follow the manufacturer's maximum filling level, and remember that any oil remaining in the tank reduces the amount you can order.

Will it fit the available space?

A tank's footprint is only part of the space you need. There must also be room for the base, and enough clearance around the tank to inspect it, maintain it and fill it safely.

Typical OFTEC separation guidance includes 1.8 metres from non-fire-rated buildings and 760mm from a non-fire-rated boundary, such as a wooden fence. Doors, windows, eaves and flue terminals also affect positioning. Where standard distances cannot be achieved, an installer must assess suitable fire protection.

The base should be level, non-combustible and capable of supporting the full tank, extending at least 300mm beyond its sides. An existing base will not necessarily take a new tank, so have it checked.

Measure the delivery route too: gates, narrow passages and tight corners can influence which model you choose.

Check the installation and total cost

Before buying, have an installer confirm that the tank's outlet arrangement suits your boiler and pipework. Top and bottom outlet options work differently, so check this before you commit.

Ask for a quotation covering the tank, delivery, base preparation, connections, any fire protection and removal of the old tank. Confirm which building control or planning requirements apply locally.

Arrange a site assessment before placing your order. It will tell you what capacity you need, what protection is required and where the tank can go, before you have spent anything.