Differences between oil and gas boilers

When deciding on a new boiler for your home or property, it’s important to make the right choice that fits your needs and location. In this blog, we’re exploring the differences between oil and gas boilers so that you can decide which is best for you.

Do you need a new boiler?

It isn’t always necessarily obvious if you need a new boiler. Existing ones may last for 12 to 15 years if they are well maintained. However, older boilers often display signs of ageing, and telltale signs include rooms taking ages to heat up, strange noises or water tank leaks. Whilst you can still get your boiler serviced and repaired, a new boiler is probably more efficient and cost effective in the longer term. Many boilers arrive with warranties, sometimes with as long as 12-year guarantees. For instance, if a cheap boiler with a short-term warranty frequently breaks down over its 15-year lifetime, you could end up paying more than if you had opted for the 12-year warranty.

Boiler systems

The combination boiler, otherwise known as a gas combi boiler, is the most common type of British boiler system. It is self-contained and there is no need for any cylinder or extra tank. Neat and compact, it can easily squeeze into something like a kitchen cupboard. It is ideal for a small occupancy household where hot water is only used for one purpose at a time.

A conventional boiler requires a loft-based cold-water tank. It has extra parts and needs a lot of space compared to a combi unit. With hot water stored in tanks, conventional boilers are better suited to bigger households where different people might opt to use hot water simultaneously.

Then there are system boilers, or closed vent boilers, if you require a heat only boiler. The external features of this option are generally built in, as with the combi boiler. It still uses a hot water cylinder, but doesn’t require an extra tank up in the loft for expansion, and needs less room than the conventional boiler.

Gas and oil boilers: which one is best for you?

Research and identify the appropriate boiler for your property. Any boiler MUST be able to cope with a different set of demands, including the property size, output power and ability to handle mains pressure. Boilers will operate slightly differently depending on the energy source. Gas boilers and oil boilers work on the same principle in how they generate heat. Natural gas is supplied via the energy grid, whilst oil is delivered to homes and stored in a tank.

Oil boilers

In their favour, oil boilers are ideal for rural or isolated homes and free up space and minimise noise when they can be installed outside the building. This makes them easier to regularly maintain and refuel, reducing the risk of exposure to carbon monoxide. However, they can be impractical in smaller gardens. Additional issues can arise if oil supplies are not topped up or do not arrive on time.

Gas boilers

Gas boilers are cheaper to service, more energy efficient and also ‘greener’ if you are concerned about carbon emissions. Liquified petroleum gas (LPG) is a cleaner burning fuel which generates less soot and ash than oil boilers. Regular maintenance by a professional minimises the likelihood of gas leaks, prolongs the life of the boiler and ensures it runs at optimal efficiency.

What is cheaper to run: a gas or oil boiler?

Acquiring a new boiler is never cheap. Get a few quotes to compare and get the best deal you can. The cheapest one may not always be the right one. Oil prices are pegged to the price of crude oil, meaning they can fluctuate, especially in winter when demand is higher. Oil is more expensive than energy-efficient gas.


The price of your boiler installation depends on several factors, including the type of boiler, whether it’s new or just a replacement, any boiler relocation on the premises plus any optional extras like smart controls. When weighing up price, reputation and convenience, we recommend that you choose your trusted local supplier.

Select a trusted brand

If you find the range of boilers daunting, choose a trusted brand. Cheaper boilers won’t necessarily offer the same guarantees as one of the reliable brands. Where gas is concerned there should be no cost-cutting at the expense of safety. When in doubt, alwaysconsult an engineer.

Worcester Bosch’s accredited service partners provide professional heating engineers, boiler installation and repair, supporting customers in Chester, Wrexham, Mold and Oswestry since 2007.