If you live in a humid region, you’d know too well how humidity can make a hot day even more miserable. Humidity is always a part of our environment, but there is only a certain range of humidity levels where we can remain comfortable and healthy. Ideally, indoor humidity should be around 30% to 50%, adjusted depending on the temperature. High relative humidity makes high temperatures feel even hotter.
Too little or too much humidity can have many negative effects. On the low end, a lack of humidity can cause skin dryness, nasal congestion, and exacerbated allergies and flu symptoms. However, in excess, it can also trigger allergies and lead to mold growth that can damage different materials.
To maintain indoor comfort, it’s essential to control the relative humidity, particularly during extreme weather conditions. Unbalanced humidity levels can intensify the impact of these conditions on your health and surrounding. Below, you can learn more about the effects of humidity and its changes.
What is Humidity?
Some amount of water vapor is always present in an environment where there is heat and any water source. While any part of your house can become humid, certain areas may be more prone to moisture than others. For example, bathrooms always have some moisture or steam and a basement or crawl space is typically damp and cold due to its location underground. In general, if the humidity level outside is high, then the humidity level inside is likely also high.
What is Relative Humidity?
We usually refer to the relative humidity (RH) when measuring humidity levels. It is the percentage of the amount of water that is actually in the atmosphere relative to the maximum amount the air could hold at its current temperature.
We also refer to the dew point when talking about relative humidity. This is the temperature at which the air becomes saturated, equivalent to 100% relative humidity.
At a higher temperature, the air can hold more water. The closer the temperature to the dew point, the higher the relative humidity. The relative humidity changes when either the temperature and moisture level changes. In the same environment, you could get a higher relative humidity with warmer air or lower relative humidity with colder air, and vice versa.
What is Absolute Humidity?
When talking about humidity levels, the absolute humidity also comes up. Compared to the relative humidity, the absolute humidity is not relative to the temperature. It is simply the amount of water vapor actually present in the air, measured in grams per cubic meter of water vapor. Thus, with the same absolute humidity, the relative humidity is higher in cold air (when the temperature is closer to the dew point) and lower in warm air.
What is the Ideal Relative Humidity Levels?
To maintain comfort, the ideal indoor humidity levels range from 30% to 50% RH. Variations within this range may be preferred depending on factors such as the ambient temperature. In most cases, anything below 30% is considered too low. It can cause dry skin and chapped lips and at worst, even lead to nosebleeds, dehydration, and common cold and flu symptoms. Special cases wherein the temperature is below freezing may warrant ideal humidity levels no higher than 30%.
On the other hand, humidity levels above 50% is considered high. During summer, humidity around 55% may still be acceptable, but 60% and beyond start to feel heavy or sticky to most people. High humidity indoors can cause mold growth and pest infestation. Musty smells, condensation on windows, and damp stains on walls and ceilings are some of the common effects of excess humidity.
Why Does Humidity Make You Feel Hot?
High relative humidity creates a muggy, unpleasant environment. You may say that your skin feels sticky during humid weather. This is because the air is already saturated with moisture and your perspiration cannot evaporate into the damp air. This causes the sweat to stick to your skin.
When the body temperature increases, your body produces sweat to help cool off your body heat as the sweat evaporates. And so, if the sweat cannot evaporate, it makes you feel even warmer. This is why “dry heat” often feels more comfortable.
When the relative humidity is high, high ambient temperature feels even higher. To give you a better idea of how hot the heat actually feels, we measure the heat index. This is the “feels like” temperature when the relative humidity and a few other factors are also considered. No matter the temperature, when relative humidity is higher than the optimal levels, it can feel warmer and unpleasant.
Conversely, when relative humidity is low, it can make the cold, dry air feel even colder. This is why the humidity must be balanced relative to the air temperature and personal preference.
What are the Effects of High Relative Humidity?
Besides causing discomfort, excessive perspiration due to high humidity can clog up your skin pores and lead to heat rashes, acne, and make skin conditions worse.
Also, high humidity conditions are suitable for the growth of mold, dust mites, and other microorganisms. Touching mold or inhaling mold spores may trigger allergy symptoms and asthma attacks. Dust mites are also another airborne allergen that can cause reactions similar to hay fever.
Mold and other fungi grow on walls, ceilings, furniture, or almost any moist, porous material. Once they settle on a surface, they feed off of organic matter such as wood and soft furnishings. This can damage your furniture, carpets, flooring, and your very house structure if left unattended for too long. Mold growth is commonly found in dark, damp areas such as bathroom walls, under sinks and toilets, behind furniture, or beneath the carpeting.
High moisture levels may also cause damp stains on walls, ceilings, and floors, which can lead to cracks in the drywall and gaps between the floor and baseboard. Excess moisture also affects other wooden materials, causing them to warp and rot and metals to rust and corrode.
How to Beat Indoor Humidity
If you have a hygrometer, humidistat, or any device that can measure the relative humidity levels, it helps monitor the conditions inside your home and fix any problems in a timely manner. In case the relative humidity reading is often around 60% or even higher, then you have high humidity problems. Depending on the intensity and coverage, you may need more than natural remedies, but rather an appliance to reduce indoor humidity.
A dehumidifier helps control indoor humidity by removing excess moisture from the air. If you have extreme cases of high humidity, you can greatly benefit from a good dehumidifier. Typically, a dehumidifier is useful during hot, humid summers, but you can use it at any time of the year. Depending on the intended purpose, dehumidifiers come in different types and sizes. We have guides to help you choose the best one for you.
However, if you don’t want to use an electrical appliance due to the costs and maintenance requirements, you may also try other alternative ways to help maintain proper relative humidity levels. The simplest way to do this is to open the windows to let cool, fresh air in, but this only helps if the humidity outside is lower. If you can’t open the windows, either a fan or an air conditioner can also help reduce humidity. You may also try natural desiccants or moisture absorbers such as rock salt, baking soda, calcium chloride, and silica gel.
Both the temperature and relative humidity are essential to maintain your comfort indoors. Overall, high relative humidity levels can make the apparent temperature feel higher than it actually is. So when looking at weather reports, the heat index will give you a better idea of the apparent temperature.
To prevent the above unpleasant effects, relative humidity should be maintained around 30% to 50% depending on the ambient temperature. When necessary, effective humidity control can be achieved with a dehumidifier and other natural ways.