Condensation and dehumidifiers.

I think you are right to be somewhat suspicious of the company & their claims.

Best advice is to find the source of the condensation first before spending thousand of euro's of trying to get rid of it.

Have you got gas heaters by any chance ??

If you have just moved to the property has it been empty for a long period with no windows open therefore no air circulation.

As Roland has said try to find the cause before spending any money often with false promises.

I would suggest you make a mixture of bleach and water in a spray container and was the walls and see what happens over a period of time monitoring if or how long it takes for any mold to reappear.

Modern inverter air conditioning units will cool, heat and dehumidify, and even a top make like LG costs around €400 per unit with room to haggle on installation. In summer our biggest unit set to cool to 22C fills a 5 litre bottle with extracted water in a day when the weather is at its worst imitation of Mumbai!

Air flow and daylight .Mold loves the dark and high humidity. Check no water is entering the property when you are not there.Bleach the walls and floors.De humidifier compressor type is cheaper to run than desicant type but you may never need one if you take these steps.My seller in Lancashire has been sorted with a UVC 30watt light bulb kills mold spores stone dead if they see the light in 20 minutes, UVC is used in operating thearters ,water treatment and other industry, but mark the bulb as to what it is as its very dangerous to the body and eyes like a welding flash I use a timer to turn it on when I use it every couple of months so I never see the light, it also puts out a lot of Ozone that you do not want to breath, but it WORKS for about £20.Forget others sorting it for a fortune for you.

Regards

Mike