Space heater parts can sometimes be reused between similar models. However, space heaters often use proprietary, single-purpose parts, whereas central heating systems typically use standard parts that other manufacturers use as well.
Another problem with reusing space heater parts is how space heaters are manufactured compared to central heating units. Central heating systems are typically made to be easy to disassemble and reassemble. Since they cost more to purchase and install, users expect to be able to repair broken components. They are also generally given a significant amount of space, which makes it easier to access individual components.
Space heaters, on the other hand, are designed with portability in mind, so components are placed as closely together as possible. If a part breaks, the entire unit may need to be disassembled, and parts may not be connected in a manner that makes them easy to reconnect. Some parts may even be soldered together and require expertise to reassemble.
Despite these limitations, space heater parts can often be salvaged. When a manufacturer releases a new system, at least some of the parts are likely to have come from similar older models. Simply upgrading a part or two within the system may make it reasonable for the manufacturer to rebrand the system. This is particularly true for electrical components, which can sometimes be shared between products by different manufacturers.