If you’re replacing an old combi boiler with a new one (a combi-to-combi swap), it’s generally a straightforward job that usually takes just a few hours. This process involves disconnecting the old boiler and installing the new one with minimal changes to your pipework.
However, converting from a different type of boiler, such as a system or regular boiler, to a combi boiler can be more involved. This type of conversion may require additional work, like rerouting pipes, removing old water tanks, and upgrading your gas supply, which can take one to two days to complete.