Airing
Yes.It works in the hot press because the heat energy released there is quite large compared to the volume of it.As well one has to consider that the hot press has no cold outside walls -not more than one at the most- and therefore condensation simply can't occur,the hot press is hot most of the time but an airing room would be hot only for a short time.That would mean that the walls have no time to get hot enough to avoid condensation.
Condensation can be avoided if the difference of wall temperature versus air temperature is less than 6 degrees Celsius.To achieve this the walls of the airing room either have to contain a wall heating system or the radiator(s) would have to run around the clock on quite a high temperature.At least at the openings -necessary to let out the moist air and to allow fresh dry air to enter-you would still run the risk .
There was a discussion here on AAM (at the beginning of this week?)about having a bathroom inside/at center point of the house ,it's advantages and disadvantages.One major advantage which had not been mentioned to the extense is that interior walls are naturally warmer than exterior walls and hence help avoiding condensation.
At the continent they use "dry houses" to dry corn on the cobs for example.These are shed-like constructions which allow the air/wind to blow through but stop the rain getting in.Remember that in Island people wash their clothes in winter as well-and they don't wait till summer to dry them.Even at minus temperatures water will evaporate.It all depends on the saturation of the surounding air-heat is not the essential point.In the tropical countries the washings could rot on the cloth line.
So a drying room would work-provided you invest in a lot of energy.A cloth dryer would be the cheaper (cheaper than an extension at least)and a "greener" solution as well.There are nowadays even A-rated ones available.