What is the Ideal Level of Indoor Humidity During Winter?

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Human beings have spent quite some time improving their indoor air quality; besides temperatures, a key aspect you shouldn’t forget is indoor humidity. 

But why is indoor humidity in winter important in the first place?

Humidity affects our health and thermal comfort. In simple terms, humidity determines whether we feel too cold or too hot. It also determines how healthy our respiratory system stays. 

For this reason, it is important to understand that an excess or lack of humidity could harm your body.

So, what is the ideal indoor humidity during winter? Continue reading to find out.

What’s the Best Indoor Humidity in Winter? — A Detailed Guide for Homeowners

Comfortable indoor humidity during winter should usually range between 30% and 50%. However, this will depend on how cold the outdoor temperature is. Here are guidelines on the level of humidity to maintain in your indoors based on outdoor temperatures.

  • When the outdoor temperature falls between 20˚F and 50˚F, ensure your indoor humidity levels are less than 40%.
  • Between 10˚F and 20˚F outdoor temperatures, maintain an indoor humidity of at most 35%.
  • When the temperature falls between 0˚F and 10˚F, the ideal humidity for a home in winter shouldn’t be more than 30%.
  • Once the outdoors temperatures dip between -10˚F and 0˚F, humidity levels should not exceed 25%.
  • For areas with winters ranging between -20˚F and -10˚F, always maintain an indoor humidity level of less than 20%.

Note: The high-end of this spectrum, 45% to  50%, will mostly cause condensation. And as such, it’s better to try and maintain the humidity between 30% and 45%.

How to Maintain the Ideal Indoor Humidity in Winter

If you’re eager to learn how to maintain the ideal home humidity in winter, you’re in luck. Our team at IMS Heating & Air has put together an in-depth guide that you can reference:

1. Humidity Percentage vs. your Home’s Structural Integrity

The United States Environmental Protection Agency (EPA) acknowledges that the ideal humidity level for your home in winter should be between 30% and 50%. You will need a hygrometer to determine the relative humidity in your house. However, most air conditioners come with a thermostat that helps you choose the preferred settings.

But is that all that matters? Your home’s structural integrity also influences the answer to this question.

Every house is built to withstand a specific relative humidity. Once that threshold is reached, problematic issues, like mold, are likely to occur.

Moisture is a well-known cause of problems in a house, especially if the rooms lack sufficient ventilation. Indeed, ventilation is critical when balancing humidity percentage and your home’s structural integrity.

An HVAC technician can help you evaluate the ventilation in your home and recommend the most suitable humidifier or HVAC system. 

2. Activities in Different Rooms in the House

Several activities can influence the percentage of humidity in your house. They include using appliances like dryers, steam radiators, combustion appliances like stoves, showering, and cooking.

That means that you could regulate how much you use indoor humidifiers. And a hygrometer will help you know when you reach the ideal indoor humidity during the winter.

Investigating if the air conditioning ducts are well insulated is also necessary. This will help with moisture issues, especially when dealing with excessive moisture.

Fixing the insulation problem could help you achieve the ideal humidity for your home in winter. Another example is air drying clothes in a room that is not directly connected to the main rooms, such as the living room and the bedrooms.

3. Using Portable or Whole-house Humidifiers

By now, you already know that a humidifier is the most effective and reliable way to increase indoor humidity, especially during the winter. You use either a portable humidifier or a whole-house humidifier attached to the HVAC system. But perhaps the most important thing to consider here is getting a suitable model that matches your home’s size and moisture needs.

If your option is to get a large humidifier, it is highly recommended to contact a qualified technician to guide you through the process. And if you choose to use portable humidifiers, you can either use ultrasonic or evaporative ones.

Portable humidifiers are, however, limited to single-room use. 

Benefits of having the Right Amount of Humidity in the House

Achieving the ideal home humidity in winter is paramount. 

But why should you care that much about humidity levels? What are the benefits of having the right humidity levels in your home?

1. Improved Health

It’s no secret that dry air can wreak havoc on your health. Some viruses and bacteria grow in dry air and also spread more in such conditions. This can cause frequent occurrences of flu, cold, sinus infections, and several other respiratory issues.

Too much humidity isn’t ideal, either. There are other types of bacteria that will thrive in moist conditions, such as mold, which can also cause respiratory issues.

Having the right amount of moisture in your house during winter is, therefore, essential in maintaining a healthy household.

2. Protection for Furniture

Less indoor humidity can cause your furniture, such as chairs and tables, to dry out and crack. In addition, floors, doors, and window frames can also suffer the same fate if you don’t maintain the right indoor humidity levels.

Ensuring that you have the right humidity levels protects your home’s furnishings, ensuring they stay in pristine shape for even longer. Doing this can save you a substantial amount of money in replacement costs.  

3. Better Sleep

Who doesn’t love uninterrupted sleep, especially after a long day at work? Dry indoor air can mess this up, causing you to stay for long without sleep and depriving you of much-needed rest.

More moisture in your bedroom improves your breathing, reduces snoring, and prevents respiratory system irritation. All these help you to get quality sleep and wake up ready for the next day’s challenges.


If your home is too humid or not humid enough, you can contact our team at IMS Heating & Air. We can help you find the perfect solution to your indoor humidity problems.