Quite conspicuously, the dehumidifier of yesteryear is quite noisy. It could be quite an ordeal to have to sleep in a room with one until you could get used to the noise. Of course, noise will in most cases lead to low quality sleep and will offset the comfort that you wanted to get out the appliance in the first place. Quite noticeably, dehumidifiers today are so much quieter thanks to many new technologies and design improvements. The new generation of dehumidifiers tends to be a lot more energy efficient as well.