Regular boilers and system boilers have some similarities, but differ in their components:* **Regular boiler (conventional boiler):** Needs several external components, including a cold water tank (usually located in the loft), a hot water cylinder (often in an airing cupboard), and an expansion tank. It takes up considerable space due to the separate tanks..* **System boiler:** A more compact system, as some components are integrated within the unit itself. This means it takes up less space and is easier to install than a regular boiler..The best choice depends on the size of your home and your hot water needs.