There has been lots of debate over many years about the extent to which hospitals should provide single rooms for patients. Should every patient have a single room for the sake of privacy? Would this help to reduce HCAI? And would it be safe even if it did? A recent review suggests that more single rooms equals less HCAI. The systematic review found that hospital wards with more single rooms had lower rates of HCAI. This makes sense: physical segregation of patients with infectious agents is an ancient approach to preventing transmission. However, whilst the evidence that single rooms reduces HCAI is compelling, there are other reasons why a mixture of single rooms and bays may be a better approach. Some patients benefit from the social aspects of communal bed-spaces. Also, when things go wrong, there is some evidence that patients in multi-occupancy bays are helped more quickly and have better outcomes. On the balance of this evidence, it may be that a mixture of single rooms and bays is the best design for a hospital of the future. The UK recommends at least 50% single rooms for new hospitals, which would seem a sensible approach based on the current evidence!