Dehumidifier
Not a cleaning tool at all, and the most effective single purchase against mould — because it treats the cause the spray bottle cannot reach.
In detail
A dehumidifier removes water vapour from indoor air, either by condensing it on a cold coil or by adsorbing it onto a desiccant wheel. It matters for cleaning because the authorities on mould are unanimous that the moisture problem is the problem: the US environmental regulator's guidance states that unless the moisture source is corrected, growth returns, and a state health department's guidance frames control of indoor humidity as the primary measure rather than a supporting one. Every mould spray in every bathroom removes a symptom that will return on the same timetable it returned on last time. Lowering the relative humidity, ventilating after showering and cooking, and drying wet surfaces changes the timetable itself. A dehumidifier is also the reason a wetted carpet or a washed upholstery panel dries in hours rather than a day, and drying speed is what decides whether a cleaned soft surface develops an odour or brown wicking marks afterwards. It is not a substitute for fixing a leak, a cold bridge or a failed damp course, and it should not be treated as one.
What works
Dehumidifier is effective against Mould Supported
Sources for this page
Sources
A Brief Guide to Mold, Moisture, and Your Home
United States Environmental Protection Agency (EPA), Office of Air and Radiation, 2012 · Government or regulator
Relied on for: That controlling indoor moisture is the primary measure against mould growth and that mould returns where the moisture source is not corrected. (states this directly)
Minnesota Department of Health · Government or regulator
Relied on for: That controlling indoor humidity and drying wet materials promptly are the measures that prevent mould growth. (states this directly)