The concept of central heating is not one that the Japanese have caught on to. The common heating model is to have independent heating and cooling units in each room.
The benefit is that you gain room by room control which can be more energy efficient. The downside is that each room is different and there is no ability to add a central humidifier as you do in a forced air system.
As the weather moved from insane scalding hot (August) to a beautiful warm fall and now into their winter the humidity has changed (Insert Canadian scoff at 8C winter .. The other day I walked to a restaurant without a jacket and everyone around me must have thought I was nuts as they were bundled like it was -10).
Returning from holiday it became very apparent that we had a problem with humidity, as the apartment had become unbearably dry. A brief conversation with the building manager brought out that every gaijin complains about it each year and then goes out and buys more humidifiers. The Japanese can figure out how to store data on glass for 10’s of millions of years, but when it comes to central humidity it is a no go.
The only option? Buy a few humidifiers. In our case 6. What a pain.