Combi vs System vs Conventional Boiler: What's the Difference?

Choosing a new boiler can be challenging, especially when trying to understand the differences between each type. You need a boiler that not only suits your home and lifestyle but is also reliable and cost-effective.

In this article, we'll guide you through the main differences between combi, system and conventional boilers. This way, you can determine which type of boiler is the ideal fit for your home.

With over a decade of expertise in boiler installation and maintenance, Surrey Heating Specialists are committed to helping you make an informed choice that aligns with your specific needs.

Combi vs system vs conventional boiler – what’s the difference?

A combination (combi) boiler is a compact unit that’s usually hung on a wall. It generates both your heating and hot water without the need for a separate hot water tank.

A conventional (also known as ‘heat-only’) boiler has a water tank. It heats your radiators up directly and connects to a separate cylinder or tank to provide hot water.

System boilers are similar to conventional boilers, but are a modern upgrade on the older model. Unlike a conventional, they don’t need both a hot and cold water tank and their pumps and valves are built-in.

Which boiler is right for me?

Combination

As they are wall hung, combination boilers are space-saving singular units, making them ideal for smaller houses. They’re also highly energy efficient – helping you to save money on bills. Plus, they’re easy to install, cheaper to maintain and easy to service, as most engineers are trained to work on combis. If you want instant hot water without having to wait for a tank to heat up, combis are best.

If you have more than one bathroom, combis can be limiting because the water pressure and flow rate will drop if people are showering at the same time, or if more than 10 radiators are in use at one time. Combis are also reliant on the water pressure from the mains – if it’s low, it’ll impact their function. There are also more moving parts, so the boiler is at increased risk of breakdown.

Conventional

Larger, older households with more than one bathroom benefit from a conventional boiler. Hot water can run from several locations at once and they don’t rely on high mains water pressure. They’re also compatible with solar heating systems and can be more cost-effective to replace.

You do have to wait for water to heat up with a conventional boiler, as water is stored in an external cylinder. Once the hot water tank runs out, you have to wait for it to refill before you have hot water. Overall, this means less efficiency and a more expensive installation cost. You also need the space to store both a hot and cold water tank/cylinder as well as the boiler itself. If this is in a cold spot like an attic, this can result in either leaks or system freeze in winter months.

System

Like a conventional boiler, a system needs an external hot water tank or cylinder – but they don’t need one for cold water. All components are integrated to take up less space, meaning a quicker install, as there are fewer pieces to fit.

As with combi boilers, system boilers rely on mains pressure, so you can face issues with flow rates or water pressure.

Find the right boiler with Surrey Heating Specialists

Looking for a new, energy-efficient boiler? Surrey Heating Specialists are here to help. With over a decade of experience, we install over 200 boilers annually, ensuring top-quality service. Enjoy the benefits of 0% interest financing, speedy installations within 48 hours, and up to 12 years of manufacturer’s warranty.

Call us now for an instant quote and experience the warmth of exceptional service! If you have further questions on which boiler type is right for you, chat with our team today. Get in touch on [email protected] or 01784-252-107.