Today more than ever, people are demanding higher-quality housing, and therefore, there is an increasing need for scientifically sound methods of systematic housing assessment that are capable of addressing multiple, conflicting, and irreconcilable aspects in both qualitative and quantitative terms. Existing studies and models often use a relatively small number of indicators and consider housing quality from a single perspective. This paper presents a methodology used to develop a model for assessing the quality of multiple conflicting spatial characteristics of an apartment. Through a literature review and a survey of 12 architects, 24 spatial indicators were identified and then classified into five categories: (i) additional rooms, (ii) room size, (iii) window orientation and ventilation, (iv) circulation, and (v) spatial organization. Finally, the overall rating of the apartment is calculated as the sum of the ratings of all indicator categories, where the share of each category in the overall rating and desirable characteristics of the apartment is determined by the user. The model was tested on the example of two apartments in the city of Osijek, Croatia.