A small boiler is a type of heating system that is typically used in residential and commercial buildings. It is designed to provide hot water or steam for heating purposes, and is usually much smaller than a traditional boiler. Small boilers are usually wall-mounted and can be powered by either electricity or gas. They are usually more energy-efficient than larger boilers, as they use less fuel to produce the same amount of heat. Small boilers are also often more cost-effective, as they require less maintenance and can be installed in tighter spaces. They are ideal for smaller buildings, such as apartments, condos, and single-family homes, where space is limited. They are also ideal for areas with low water pressure, as they are able to provide hot water even when the pressure is low.