I have to run a dehudifier in my house often when I do cakes. Especially fondant cakes. It does help. Not drastically but it helps some. My air conditioner is also old and too small for our equally old house so battling the heat and humidity is always an issue for me. Working early in the morning or at night with the AC turned down as low as it will run (which for me still doesn’t get too cool!) with the dehumidifier helps. I can’t always work at night though. Good luck to you this is an issue many of us in tropical zones face.