Mildew is generally not as harmful to human health as certain types of mould. While mildew can cause some respiratory irritation or allergic reactions in sensitive individuals, it is typically less severe than the health risks associated with mould, especially toxic moulds like Stachybotrys.
Mould can produce mycotoxins that pose more significant health threats, particularly to people with allergies, asthma, or compromised immune systems, according to the NHS.
Additionally, mould can penetrate and damage building materials, leading to structural issues in a home. So, while mildew is an annoyance and should be addressed, it is generally not as dangerous as certain moulds, and mould should be dealt with more urgently and professionally.