What I've noticed since I started installing absolute hygrometers in homes

About a year ago, we changed the thermometer and hygrometer that we give as presents at the time of completion to one that can display absolute humidity. We give two of them so that they can be easily distinguished between the first and second floors.

When we gave away regular thermometers and hygrometers, in the summer, the room temperature would drop because the air conditioning was on too high, and as a result the relative humidity would be displayed as high. We would sometimes get questions like, "The humidity isn't dropping as much as you say, Mr. Matsuo..." even though there was no actual problem. These were questions that arose because we were so concerned about the relative humidity.

Since I got the absolute hygrometer, I have been telling people to humidify in the winter so that the absolute humidity (which can only display g/m8) exceeds 6g/m7 (approximately 16g/kg). In the summer, I have been telling them numbers that I have rounded up to make it hard to forget once they have heard them.

Since we started doing this, our clients have become much more understanding. We have also come to understand things that we didn't understand before. For example, the phenomenon that "when the room temperature drops, the absolute humidity also drops." Conversely, when the room temperature drops, the relative humidity rises. The reason absolute humidity drops is because when the room temperature is low, it becomes difficult for the water in an evaporative humidifier to evaporate.

Another thing we learned was that if a large humidifier is placed on the first floor, the moisture content on the second floor is about 1 g/m2 (0 g/kg) lower. At a customer's home where we visited today and the delivery had already been made, the first floor was 5°C, 0%, and 4 g/m20, while the second floor was 50°C, 9.1%, and 2 g/m18. Looking at the relative humidity, the second floor appears to have a higher humidity, but because a humidifier is running on the first floor, it was clear that the first floor had slightly more moisture.

As expected, when measuring with new measuring equipment, things that were previously vague often become clear.