Ulymoon,
As Mr. Silverwood mentioned, there are some good technicians at this forum. I have over 30 years experience, and others are here who are very experienced also. Pianoworld does still have a small number of decent techs remaining from the many, many who have left...but unfortunately, they are usually not the ones who are responding there to technical questions most of the time. You can spot these few with their signatures indicating their business...the rest are wannabe's and hacks. The site has become very "American" and few there are familiar with issues related to pianos in other countries, older antique pianos and the many European pianos available worldwide.
90% of the dialogue at PW seems to center around Unequal Temperaments or what they call ET alternatives, and these are all traced to a few techs there who author them, and are trying to promote them ad naseum. They also promote substituting UTs for ET without informing clients of the change...this is considered unethical by most technicians. That is the only forum in the world where this stuff is discussed or considered viable in every day business. They can't even agree on what is a "good" tuning and absurd concepts are constantly being tabled like unisons tuned away from beatless, stretched octave intervals that beat and of course...the temperament flavour of the month.
Most regions of the world have very accurate climate data available on line where average degree days, humidity averages are logged and kept track of. Looking at these first will help you decide what type of climate control you need for what. I am not familiar with "all in one" conditioners for rooms, although the Dampp Chasers do address both humidity and dryness extremes. They have a humidifyer tank for dryness, and also heating bars which chase away high humidity, and will regulate both swings efficiently with an accurate sensor controlling it.
My personal experience with DC is good but I believe they have limits for their effectiveness. If you are in a dryer climate than 20% RH or a wetter one than 75% RH, you would likely be served better with a stand alone humidifyer and a dehumidifyer. Upright pianos seem to fair a bit better than grands for Dampp Chaser effectiveness at the extremes, mainly because the unit is fully contained in the cabinet.