>The FMR estimates include utility costs and vary depending on the number of bedrooms in each unit, from zero to four bedrooms. We assumed that a one adult fa

>The FMR estimates include utility costs and vary depending on the number of bedrooms in each unit, from zero to four bedrooms. We assumed that a one adult family would rent a single occupancy unit(zero bedrooms) for an individual adult household, that a two adult family would rent a one bedroom apartment, and that two adult and one or two child families would rent a two bedroom apartment. We further assumed that families with three children would rent a three bedroom apartment (the adults are allocated one bedroom and the children two bedrooms). So they covered their assumptions in their technical documentation that is linked at the top of the page. The increase in housing costs seems reasonable to me personally but as with all assumptions not everyone will agree.