NCIDQ IDFX Practice Exam

How is the efficiency factor calculated?

1. Available area divided by total area

2. Net area divided by usable area

3. Usable area divided by rented space

4. Rented area divided by total building area

The correct answer is: Net area divided by usable area

The efficiency factor is a key measurement in evaluating the functionality and layout of interior spaces within buildings. It is calculated by dividing the net area by the usable area. Net area refers to the actual space that is usable for occupants, which includes all work areas but excludes areas such as walls, corridors, restrooms, and other non-usable spaces. Usable area takes into account the total area available for tenants, which encompasses both net area and some common areas that are shared among occupants, but it typically does not include the totality of building facilities. By using the ratio of net area to usable area, the efficiency factor provides insights into the practical usability of space in context with the overall design and layout. A higher efficiency factor indicates a better ratio of usable space to total area, suggesting that more of the overall space is functional. This makes it a critical consideration for interior designers and architects when striving for efficient layouts that maximize the use of space. The other choices do not provide the appropriate context or formula for calculating the efficiency factor in terms of interior design and commercial space planning.