Dyson Purifier Hot+Cool Formaldehyde HP09chat_bubble_outlineFrom real comments

Setup instructions leave new owners guessing. One first-time owner unboxed the HP09 and found two different filter sets, small blue and larger grey, with no clear guidance on which goes where. The printed instructions inside the box were described as basically providing no useful information, and the reviewer had hoped an accompanying video would demonstrate filter insertion but found none. This left the impression of a promotional piece rather than a practical guide, suggesting Dyson could improve its included documentation and video support for people unfamiliar with the machine's filter system.

Filter construction differs noticeably between Dyson purifier models. A commenter who owns both a TP09 and an HP09 noted that the catalytic filters look quite different: the TP09's filter appears more metallic, while the HP09's is thin, resembling a mesh of fabric and foam at the base. They asked whether this construction difference actually affects performance, since Dyson doesn't clearly explain why the catalytic filters vary across models. This ambiguity around filter types adds to buyer uncertainty when comparing models.

Long-term reliability is praised, but heat mode showed odd behavior. One user who ran a cold-only Dyson formaldehyde purifier for two years described it as great, prompting them to upgrade to a hot-and-cold model, suggesting durable long-term satisfaction with the platform. However, another buyer of the actual HP09 reported that after setting the fan to speed 10 in heat mode, the fan dropped to roughly speed 1 within a minute while the display still showed 10, raising doubts about whether this was intended behavior or a fault.