For keeping the elderly people living safely and in good health ‘at home’, various systems, which we called ‘Informational Care Systems at Home’ (ICSH), are being developed using informational technologies these days. One of these systems, the emergency-call system, is now introduced in more than 80 percent of municipalities in Japan, so it could be considered as one of the representative models of these systems. On the other hand, systems such as ‘the tele- monitoring system’ using network technology are also developed actively, in order to deliver information between family members beyond spatial distances. In this paper, we focused on the cognitive barriers to use these ICSH and hypothesized their causes from the users' personal view: that is, these ICSH systems can be thought as the transmitter of users' private sphere, that is the dual concept of public sphere. In the private sphere, people have controls on information delivery as what can be given to whom, in which the recipients are such as family members, doctors, friends, or neighbors. With ICSH systems, the residential users' controllability on information change in a drastic manner, therefore, these systems cause implicit and cognitive barriers to use. To verify the hypothesis, interviews with 6 people who were users of the emergency-call system were conducted, and found positive evidences for our hypothesis; the existence of the cognitive barriers, needs on controllability on information delivery at home, and also lack of mental models of the emergency-call system itself. With these results, the possible ways to design ICSH to be user centered was discussed.