A combi boiler is more modern than a regular boiler. It is the most commonly used system in all of the UK. A combi boiler is a single unit which does not require a tank or a hot water cylinder. Combi boilers draw water directly from your mains and provide you with hot water on demand. On the other hand, combi boilers are only suitable for smaller homes without much demand for hot water. As a result, they are inconvenient in larger homes with a high hot water demand. That’s why you should always make sure to choose what’s right for your home and needs.