In France, 53% of dwellers live in single family detached houses, which are considered to be the ideal home by almost 90% of the population(1). The construction of this type of houses has progressed 12% in the last few years, representing, for the year 2000, 61% of all residential buildings. In spite of an increase in building and land costs, the construction of suburban houses has progressed 9,6%(2). This market is almost completely controlled by building contractors and developers leaving only 5% in hands of the architects(3). The reason why architects can be sidelined is legal: only constructions above 130 m² (approx. 1300 sft.) require the signature of an architect. But this is not the only reason, according to Monique Eleb(4), the majorities of the French are «frightened» by the architect and prefer to deal with a building contractor or developer, they dread a possible conflict between their desires and the propositions made by the architect. The differences go beyond aesthetic and stylistic considerations, previous research(5) has pointed out the importance of the factors of ambience for the clients specially for the living-room space. We refer to “ambience” or “ambient environment” as the ensemble of perceptions that a person can have of the interactions between the built space and the natural phenomena (sunlighting, solar loads, air flow, heat transfer, humidity, noise transmission, etc). This research is interested in the differences between architects, building contractors and there clients. The studies that compare architects and clients take two main directions: one analyses their preferences and perceptions of architectural styles and aesthetics, the other studies how they interact during the conception process. Our research takes a different approach by analyzing house plans produced by architects and building contractors for a specific client and for architectural competitions (no specific client) and we focus on the characteristics of the ambiences produced by each group for each kind of client. The sample consists of two groups of affordable medium-sized detached houses located in northwest France near Nantes. The first group is a real-estate development of 225 houses with independent clients of which 72% (162 houses) were produced by developers and 28% (63) by architects. The second sample is the result of two architectural competitions – one of which was patronized by a real-estate developer – it includes 74 projects for affordable houses but with no specific client. The research studies the spatial features of the sample in order to characterize the living-room space according to: 1) size, form, proportions and plan organization; 2) solid/void ratio of closing elements; and 3) orientation of openings. The results show little difference between the ambience produced by architects and developers when there is a specific client. On the other hand, there are great differences between the ambience of project presented at the architectural competition and the real-estate development, the former seem relegated well after formal and stylistic considerations. A typology of the ambience of the living room is advanced.