In this paper, to better understand indoor humidity in cold regions where it is more difficult to maintain indoor humidity in winter and to obtain basic information for improving indoor humidity, we evaluated thermal environments from measurement data in special nursing homes for the elderly of Miyagi and Hokkaido, and estimated the lack of humidification from an analysis of ventilation amount in these cold regions. From the measurement data, it was shown that the indoor temperature and CO2 concentration were almost within reference ranges, but the relative humidity was less than 40% in most facilities. From an analysis of ventilation amount and required humidification amount, it was shown that the ventilation amount changed according to various situations, and that humidification rates could be below 50% when carbon dioxide concentrations were controlled to 1,000ppm.