The amount of water vapor, the invisible gaseous state of water, in the air is better known as humidity. The amount of moisture in your home is determined by air temperature and air pressure. Depending on the season and personal preference, the ideal indoor humidity levels in your home should range from between 30 percent to 50 percent (relative humidity). The goal is to be between 35 percent and 40 percent. Health experts agree that this is a comfortable humidity level for pets as well.

Indoor Humidity in Winter vs Summer

Indoor Humidity

Outdoor temperatures play a major role in indoor humidity levels. Indoor air quality and the health of occupants are affected by the moisture in a home’s foundations, walls, and roof. The lower the outside temperature, the more excess moisture there is likely to be inside.

Cold, moisture-laden air finds its way indoors through cracks and drafty doors and windows, and condensing on the surfaces, as it clashes with the warmer air indoors. For example, if the outdoor temperature is between 25 degrees Fahrenheit to 50 degrees Fahrenheit, the humidity levels of the indoor air will be around 40 percent.

Winter Humidity

In the winter, indoor humidity drops to be between 25 percent and 35 percent. Keeping humidity levels higher than that will be difficult due to the cold climate. Contrary to popular belief the furnace does not dry out humidity.

Cold air is dry, therefore, the air becomes drier as it finds its way into the house. Cold air can enter through drafty doors, older windows with broken seals, as well as through the roof.

The challenge in the winter is to keep the humidity levels low enough so that condensation doesn’t form inside. Try to do so while keeping humidity high enough to ward off static electricity and dry skin.

Furthermore, dry air can cause discomfort and illness such as sore throats, sore noses, sore eyes, the flu, and even allergies. Dry air can also support the spread of viruses.

Do your best to keep the cold dry air out to prevent sickness and higher heating bills. If the indoor air remains very dry, use a home humidifier for better humidity control.

How to Increase Humidity Indoors in the Winter

Although using a humidifier to add moisture to the air in your home is the easiest way to control humidity levels, these other options work just as well. To add moisture to dry indoor air in the winter you might consider the following.

  • Adding houseplants is not only great for decorating, but it will also help purify the air and add to the humidity level.
  • Boil water and cook using the stovetop to release steam into the air while you prepare food.
  • Set out a pan or vase of water near heating vents.
  • Hang dry laundry. Not only will moisture enter the air, but you will also save on energy costs as dryer usage decreases.
  • Open the bathroom door to release shower steam into your home.
  • Leave bathwater in the tub to cool down before draining.
  • Upgrade doors, windows, and weatherstripping to keep heat and moisture from leaking outside your home. You might also consider installing new modern windows. This is also a great way to save on home energy bills.

Types of Humidifiers

Humidifiers add moisture to the add to ensure the air in your home is not dry. There are many factors you need to consider before purchasing a humidifier. Such factors include your budget and the size of your home or room that you need to add moisture to.

Warm Mist Humidifiers (Steam Vaporizers)

Warm mist humidifiers use boiling water to increase moisture content in the room. This type of humidifier is great for people who have nasal congestion or an irritated throat.

Cool Mist Humidifiers (Evaporative – Ultrasonic – Impeller)


Evaporative humidifiers add moisture to rooms using the basic principles of evaporation. The fan in the humidifier pulls in air and blows it through a wick filter at the base of the humidifier. This causes the water to evaporate and turn into water vapor which is then released back into the room.


Ultrasonic humidifiers use high-frequency sound vibrations to create water vapor that is expelled back into the room. Because this humidifier uses ultrasonic vibrations instead of a fan, this type of humidifier is much quieter than those that use a fan.


This type of humidifier uses a rotating disk to fling water onto a diffuser. The diffuser then breaks down the water into tiny droplets which then are released into the air. You must clean the humidifier often in order to prevent bacteria and/or minerals from being released into the air and inhaled.

Whole-Home Humidifiers

This type of humidifier is built into your HVAC system and is best for adding moisture to your entire home. A whole-home humidifier is a great option for people living in dry climates.

Summer Humidity

High humidity, over 45 percent, can leave rooms feeling clammy and sticky which can be unbearable. A humidity level of over 50 percent isn’t just uncomfortable, it can also cause health issues and higher HVAC system bills.


While heat is good for preventing the spread of viruses, excessive humidity can lead to condensation on your windows, bacteria, mold growth, and mildew which can spread easily. This happens when cold air blows against warm, moist interior walls, causing condensation to mix moisture and mold spores. Mold spores can then become airborne and be inhaled into the lungs. This can provoke allergies and result in respiratory conditions such as asthma.

In addition to causing discomfort and health issues, high humidity levels can be problematic for your house. Moisture in the air can rot framing, roofing, and flooring when excess humidity is present.

How to Reduce Humidity Indoors in the Summer

While everyone loves the warmth and sunshine of summertime, most people would say they don’t enjoy the outdoor or indoor humidity in the summer. When your home’s comfort is being overrun by warm air and levels of humidity exceeding 45 percent, even with a dehumidifier running, you might find the following tips helpful for dehumidifying the air.

Utilize Fans & Proper Ventilation

Turning on ceiling fans, floor fans, and exhaust fans is an effective and inexpensive way to reduce the temperature and humidity in your home. As the fan circulates the air in your home, the breeze evaporates excess moisture, causing the room temperature to drop.

Be sure to have ceiling fans working in a counterclockwise motion in order to maximize their effectiveness and push warm air downwards. Also, when you are cooking, cleaning, and bathing, be sure to turn on exhaust fans so the hot, warm air from your home can release outdoors.

Install A New Air Conditioner or Schedule HVAC Maintenance

When battling excessive humidity during the summer months, it is easy for an old air conditioning unit to overwork and malfunction. The best solution to controlling humidity levels in your home is to install an air-conditioning unit that can dehumidify in summer and add moisture in the winter. This popular HVAC upgrade will not only help to regulate humidity but will also help to lower heating and cooling bills in the summer and winter.

Tips for Saving Money on Summer Energy Bills

Monitor and Manage Indoor Humidity Levels

Be proactive and measure the indoor humidity levels to pre-empt skin dryness or asthma. Invest in a digital Hygrometer Indoor Thermometer to obtain accurate readings of humidity levels in your home. A hygrometer will allow you to manage the air-conditioning and or humidifier, to help keep heating and cooling bills under control while keeping the family healthy and comfortable all year round.

Additional Reading: Moisture Control via

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