Humidity and Mold Management
High indoor humidity can be hard to control. Often people use their air conditioners to remove moisture from their home, since this happens as a by-product of cooling. However, dehumidification is not the primary purpose of an air conditioner. An air conditioner runs off of a thermostat which only senses temperature, not humidity levels.
When it is hot and humid outside and you run your AC all day, an air conditioner works fine to remove humidity. But if it is not hot enough to run your AC, the humidity levels outside may still be high enough to be uncomfortable and consequently the humidity level in your home is high too. It might be rainy and cool outside, wet enough to be humid but not hot enough to run your air conditioner.
- It only takes between four and six pints of water to raise the humidity level of a 1,000 square feet from 15% to 60%.
- The number of people in your home will affect the humidity level since one person breathing can produce up to 1/4 cup of water in an hour.
- Some mold can grow when the relative humidity level is above 50%. Most molds like relative humidity above 60-70%.
- You should have a hygrometer in your home to measure the temperature and relative humidity. Ideal relative humidity is 40-50%.
- Mold needs 3 things to grow: moisture, warmth and food.
- Mold decomposes dead organic materials like wood and materials made from wood, such as paper.
- Molds can digest some synthetic things such as pastes, paints, or adhesives.
- Molds secrete digestive fluids that decompose the substrate and make nutrients available.
- Mold cannot digest nonorganic materials like concrete, plastic, glass or metal, but it can digest a possible layer of dirt or dust that coats the surface of these.
- Typically relative humidity about 60% is needed to provide the moisture a mold needs to grow.
Humidity makes a surface damp enough to permit growth.
Here is a helpful table on common causes and cures for humidity and mold in your home. Click the image to download and print a PDF copy.