There are many instances where an indoor unit of a split-type air-conditioner used in ordinary home is installed, e.g., at the upper part of a side wall because a central area or space within a room when viewed three-dimensionally or an area or space slightly below the central area is allowed to be mainly air-conditioned. In that case, a temperature sensor for sensing a room temperature is provided in the vicinity of an interior air inlet of the indoor unit.
Meanwhile, so called a free built-in type air-conditioner which can be installed in the state where such an air-condition is embedded not only in a wall portion, but also is embedded at/in any other portions such as a ceiling portion or a cupboard or closet near the ceiling, etc. is proposed as an air-conditioner for ordinary home. An air-conditioner of this type is composed of an indoor unit and an outdoor unit. More particularly, the indoor unit is comprised of a blower unit and a heat exchanger unit wherein the blower unit and the heat exchanger unit are connected through a duct. Accordingly, when the positions of the inlet and the blow-off opening for interior air are determined, the installion positions of the blower unit and the heat exchanger unit in correspondence with those positions are determined.
In a free built-in type air-conditioner of this kind, a temperature sensor for the indoor unit is provided in the vicinity of the air inlet. Accordingly, in dependency upon the installation position of the indoor unit, the temperature sensor senses an air temperature in the vicinity of the upper part of a side wall, or senses an air temperature of a space close to a cupboard or closet on the floor. As well known, an air within a room is circulated to some extent by air-conditioning, so temperatures at respective portions within the room are caused to become uniform to some degree. However, in practice, there is a considerably large difference between a temperature at the portion in the vicinity of the ceiling and a temperature of a space near the cupboard on the floor. For this reason, there exists a temperature difference which cannot be neglected between a temperature at a central portion of a room which is the position to be mainly air-conditioned and a temperature at the position where the temperature sensor is provided.
Hitherto, since any measure was not taken for such a temperature difference, for example, in the case where an indoor unit is installed on the ceiling, there were instances where heating at the central portion of a room becomes insufficient in a heating operation, or a central portion of a room becomes too cool in a cooling operation.