One of the less expensive ways of decreasing humidity in homes and buildings is to purchase a dehumidifier. Humidity control all year round is important to improve air quality, protect building components, and prevent the growth of molds, mildews, dust mites, and other allergens.
Like all household appliances, there are so many dehumidifier brands, types, and sizes to choose from. Your device should match the space of your room and the scope of your moisture problem. You should consider personal preference, your living condition, and many other factors in making your selection.
Humidity is the amount of water vapor or moisture from the air. An ideal indoor humidity ranges from 30 to 50%. High humidity can make you feel uncomfortable and can be dangerous when combined with hot temperatures.
Damp air can cause damage to construction materials, components, or systems through a number of failure mechanisms such as wood rot, corrosion, staining, delamination, mold growth, loss of insulation, dimensional changes, and freeze-thaw damage.
Indoor mold and moisture is a society-wide problem, as emphasized by the World Health Organization in a 2009 report: “The most important means for avoiding adverse health effects is the prevention (or minimization) of persistent dampness and microbial growth on interior surfaces and in building structures.”
Certainly, there is no fungal growth without moisture. Like all living systems, the development of molds requires the availability of water. Note that molds do not need to be visible to affect you; these are microscopic organisms and can be present anywhere.
Fungal development is high in areas with (1) high humidity, (2) high water content, (3) plenty of organic materials like wood, paper, insulation, and cardboard. Wood and wood-based products are not the only materials susceptible to fungal growth. Molds can grow on painted surfaces, plasters, renders, and wallpapers.
A dehumidifier is a home appliance that reduces and maintains the level of humidity in the air through a process called dehumidification. These simple machines effectively remove water vapor from damp air. High moisture content in the air can bring a number of problems:
Most dehumidifiers work the same way. The moist air is driven by a fan through the appliance, where it passes over a refrigerated metal coil. At that point, moisture is extracted from the air and is stored into a tank or drained away.
In some cases, kitchen and bathroom exhaust fans are enough to reduce humidity to acceptable levels. A typical air conditioner can also remove a certain amount of moisture out of the air, but dehumidifiers do it more efficiently. Home dehumidifiers remove between 10 liters and 50 liters of water from the air each day.
The effects of high humidity levels on your body
Have you ever wondered why humid days feel hotter than dry ones? The main reason is that humid air doesn’t carry heat away from your skin as well as dry air does.
Your body tries to eliminate heat and cool itself down through perspiration. In an ideal setting, the sweat evaporates, taking some of your body heat with it and you will feel a bit cooler.
But sweat cannot evaporate in an environment with humid air, as the air is already full of moisture and cannot hold any more water. In return, your body’s cooling process is slowed down and you feel hot and sticky.
So you don’t actually sweat more on humid days, your sweat just doesn’t evaporate. That is why it is best to use a dehumidifier in the summer, and a humidifier in the winter.
Unlike a dehumidifier, humidifiers increase the moisture level in the air to prevent dryness of the skin, nasal passages, and other parts of the body. You need a humidifier if your indoor humidity falls below 35%. They are recommended during the dry, winter season and are often used in children’s rooms.
Humidifier – adds moisture to the air
DEhumidifier – removes moisture from the air
Absorption dehumidifiers do not have compressor parts so they are lighter and quieter. They use absorbent materials or desiccants to extract water from the air and then heat it internally. They may include a heater and are able to increase room temperature by 3-5°C. These are useful in residential and industrial areas with high humidity and low temperatures.
Refrigeration or compressor dehumidifiers are the most common type of dehumidifiers. A small fan pulls damp air over a cold metal coil, which causes the moisture to condense. The droplets drip into a collecting space inside the unit (which needs to be emptied from time to time) or pumped through a drain. They work better in high temperatures so it’s best to use them during hot summer days.
This type removes moisture from the air using a fan and Peltier heat pump to create a cold surface where water can be extracted. It is quiet but has a low-efficiency rating. Peltier dehumidifiers are small and lightweight, but they are only effective in small areas like the bathroom or closet.
After deciding what type of dehumidifier you need in your home, it’s time to pick the size. The size of a unit is determined by it’s drying capacity or the total capacity to remove water. Capacity is often rated according to how many pints of water they can remove in 24 hours. Wet spaces need a dehumidifier with higher drying capacity. Medium capacity units are ideal for spaces that are not quite as damp.
Standard dehumidifier sizes
Small capacity – 30 pints
Medium capacity – 50 pints
Large capacity – up to 70 pints
Most dehumidifiers with compressors and fans typically make noise. But some models are advertised as having silent or quiet operation. These models are designed with additional insulation or a smoother-running fan to reduce noise. The average noise level for dehumidifiers is about 40 to 50 decibels (dB), closer to the level a refrigerator makes.
If you want an energy-efficient appliance, look for the Energy Star label. Models that are qualified under the Energy Star program are constructed with more efficient components such as fans, compressors, and refrigeration coils. They can remove the same amount of moisture using 15% less energy. Another thing to check is the energy factor in the unit’s specifications; the higher the energy factor, the more efficient the unit.
Humidity Control – lets you set a specific humidity level and the unit will automatically maintain it.
Automatic Shut off – if the drip pan is full and needs to be emptied, the unit will automatically switch off.
Caster Wheels and Handle – this mobility feature will make it easier to move the unit from one place to another.
Defrost – automatic defrost prevents damage from iced coils.
Auto Restart – automatically restarts the unit after a power outage–a useful feature if you are away from home
Air Filter – this optional accessory protects the coils from dirt and dust–choose models with removable and washable filter
Q: How do I measure humidity in my home?
A: You need a device called a hygrometer. You can find digital hygrometers for less than $10. You can also find tutorials on how to make a simple hygrometer (sling psychrometer), which measures relative humidity and dew point.
Q: What causes high humidity inside the house?
A: High humidity levels at home can be due to a lot of things such as drying laundry, showering, cooking, pipe leaks, and poor ventilation to name a few.
Q: Can high humidity cause health problems?
A: Although damp air in indoor environments does not directly cause diseases, it promotes the proliferation of house contaminants that can cause adverse health effects. Fungal growth or molds have been linked with upper respiratory diseases in children and adults. Dust mites and other allergens exacerbate asthma and can damage lung cells. Indoor pests like booklice, cockroaches, and springtails are also attracted to moisture.
Q: Can I use a dehumidifier in the winter?
A: You can use a dehumidifier at any time of the year. The only factor to consider is the level of humidity in your room. If you have high humidity even if the room is cold, you can run a heater for a few hours to make it easier for the humidifier to control the humidity. Dehumidifiers work best in temperatures above 50 degrees Fahrenheit.
Q: Will a dehumidifier kills mold?
A: A dehumidifier does not kill mold but prevents them from developing by reducing humidity. Bleach and vinegar can remove small outbreaks of mold, but vinegar can better penetrate porous materials. Consult a qualified repairman for major mold infestations.