To rapidly give an alarm or warning to a resident by minimizing heat input/output of interior exterior of a house in a highly airtight house, efficiently cooling or heating it, improving durability, and detecting harmful compound for effecting adverse influence to a human body.

The house A comprises an attic space 1, living space 2, an underfloor space 3 in such a manner that the space 1 communicates with the space 3 via a wall space 10 between an inner wall 8 and outer wall, a roof heat insulation sealing layer 6 and an outer wall heat insulation sealing layer 7 formed at a roof surrounding the space and the outer wall, an air supply port 9 and exhaust port 11 arranged in the space 2 in such a manner that the port 11 is connected to a heat exchanger D disposed in the housing A. Thus, the air of the space 2 is externally exhausted via the exchanger D. Meanwhile, the external air is exhausted into the space 3 via the exchanger D. The house A also comprises a sensor for detecting detrimental chemical substance contained in the air at one position in the house A, and an alarm warning unit for warning an alarm according to a signal from the sensor.