Most central heating upgrades are less disruptive than people expect. A power flush with chemical treatment is typically a day. Swapping a handful of radiators is usually done in a day, sometimes two. A controls upgrade is usually a half-day job. A full system refresh — new pipework runs, new controls, magnetic filter, flush, and radiator changes — runs two to four days depending on the property. We agree the sequence at the quote so you know what each day looks like, we protect floors and soft furnishings, and we tidy up properly each evening rather than leaving dust sheets and tools out overnight. Heating will normally be back on at the end of each day unless we've warned you otherwise in advance.