When the dewpoint of the outdoor air is +60^F, the basement floor and walls may have condensation forming and growing mold. In finished basement, it's best to keep the relative humidity below 50%. This will control mold and dust mites. Get a good relative humidity meter to monitor humidity meter. You will need good dehumidifier in regions that have green grass during the summer months. Check EPA'S Energy Star web site for efficiency ratings. Figure 50 pints capacity per 1,000 square feet.