What effect can relative humidity have on mold growth? When relative humidity is above roughly 60%, there is a risk of mold growth– with risk really increasing when the RH exceeds 80%. Elevated relative humidity can also lead directly to condensation.
Water Vapor
If there are no cold-condensing surfaces and the relative humidity (RH) is maintained below 60 percent indoors, there will not be enough water in those materials for mold to grow. However, if the RH stays above 70 percent indoors for extended periods of time, mold will almost certainly grow.
Remember, mold grows best at a relative humidity of 55% so keeping the humidity well below that percentage is your safest bet. Most modern dehumidifiers have the ability to set a minimum humidity level. Set yours right around 40% to keep mold from growing in your home.
Sometimes, humidity or dampness (water vapor) in the air can supply enough moisture for mold growth. Indoor relative humidity (RH) should be kept below 60 percent -- ideally between 30 percent and 50 percent, if possible. Low humidity may also discourage pests (such as cockroaches) and dust mites.
Let's talk about what humidity levels you should keep in your home year-round, and different techniques to do so. Ideal in-home humidity levels should hover around 45%. Anything under 30% is too dry, and over 50% is too high.
An indoor humidity level is too high when it's above 50%. At this level, your home is susceptible to increased dust mite infestations, as well as mildew, mold growth, and other bacteria. This can cause serious health issues for those who breathe in mold spores or are exposed to bacteria for long periods of time.
The Health and Safety Executive recommends that relative humidity indoors should be maintained at 40-70%, while other experts recommend that the range should be 30-60%.
Mold stays “dormant” in the air or on surfaces even when there's no excess moisture to help it grow. If the humidity in a room increases, mold will start growing in patches on walls, clothes, and more. So, to answer your question, dehumidifiers do NOT kill mold, but they do prevent it by reducing humidity.
Do air purifiers help with mold? Air purifiers help capture mold spores from the air, preventing them from reproducing and spreading throughout your home. While air purifiers won't help treat active mold that's already present on surfaces, they are a great way to control the spread of airborne mold particles.
Keep the thermostat at 78 degrees or above. A higher thermostat setting and slightly warmer air temperature results in drier indoor air. In the cooling mode, temperatures lower than 78 degrees generate more humid air and cool indoor surfaces, increasing condensation that breeds mold.
Spring and Fall are commonly known as the worst seasons for mold growth. Especially in regions with heavy rain and high water levels, the moisture can cause expedited growth. Heavy rain showers can bring the best environment for mold.
Keeping your humidity level between 30%-60% helps manage the prevention of mold growth. But active mold requires remediation to end the problem and ensure it will not begin to grow again. Mold can develop on wet or moist organic materials in your home within 24 to 48 hours of the moisture exposure.
Even when temperatures drop below freezing, mold spores don't die; they simply become dormant and will begin to multiply and grow again as soon as the temperature rises. That's why controlling the temperature alone will not solve your mold problems.
Mold generally looks slimy or fuzzy, tends to have a raised texture, and can come in a rainbow of colors, including deep green and black. Mildew is powdery, looks white or gray, always appears flat, and grows on surfaces.
Get Your Dehumidifier Settings Right: Between 30-50%!
So what is the best humidity setting for a dehumidifier? According to Energy Star, the optimal level of relative humidity in your home should be between 30% and 50%.
Some people are sensitive to molds. For these people, exposure to molds can lead to symptoms such as stuffy nose, wheezing, and red or itchy eyes, or skin. Some people, such as those with allergies to molds or with asthma, may have more intense reactions.
If you live in a humid environment and want to control moisture levels to prevent mold growth, a dehumidifier may be the best choice. Dehumidifiers are effective at reducing humidity levels and removing excess moisture from the air, which can help prevent the growth of mold and mildew.
To get the most out of a HEPA filter for mold spore removal, it should be allowed to run 24/7. This means you should check to see if the air purifier you buy is Energy Star certified, so it does not use too much electricity. Noise is another concern, especially if it will be running in an area where you sleep or work.
Ventilation fans are the best way to prevent mold build up inside a home. Think about it: what happens when a home has a flood? Typically, a water damage expert will be called in and the first thing they do is bring in ventilation fans to dry out the moisture and wetness inside the home.
Use 1 part bleach to 3 parts water, according to Sherwin-Williams. If you don't want to use bleach but do want something other than water, try vinegar, borax or branded products that you can find at a hardware store or home center, which also kill mold.
Disconnect the dehumidifier's cover to access the coil. Spray the coil with a no-rinse foaming anti-microbial coil cleaner. The foaming cleaner should drip into the water collection tank; though, follow the instructions on the type you use. Use a soft cloth to wipe down the coil and parts.
A home should have a relative humidity of 30% to 60%. Above 60% and you have what's considered “high” humidity. Besides being less comfortable, high humidity causes a host of other problems in your home, including: Growth of fungus and mold in various parts of the home.
If the levels are off, whether too high or too low, you face structural damage to your home as well as potential health issues. Comfortable levels of humidity range between 30% and 60%, however, the ideal humidity level, according to ASHRAE, is between 45% and 55%. Anything above 55% is considered to be high.
Research shows that the ideal relative humidity for your home is between 40%-60%. However, to discourage the growth and spread of mold, levels should be kept below 50%.