What is the Ideal Indoor Humidity in the Summer and Winter?

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What is the Ideal Indoor Humidity in Summer and Winter?

Are you wondering if you should be using a humidifier or dehumidifier? Learn more about the ideal indoor humidity in the summer and winter for a healthy, comfortable home.

Here, we are going to take a look at how humidity levels, both indoors and outdoors, can change from the summer to the winter months. We will discuss the ideal humidity levels for your home during these different seasons and why it’s so important that you regulate the humidity within your home, as well as some tips on how to do it.

Why Care About the Ideal Indoor Humidity in the Summer and Winter?

Whether you realize it or not, the chances are at some point in your life you have experienced some of the effects of having indoor humidity levels that are either too high or too low. Whether you’re feeling overly congested, having dry, itchy skin, or finding mold spores growing within your home, each of these could be directly caused by your home’s humidity levels being unregulated and out of balance.

Let’s start by thinking about what indoor humidity is, how it is affected by the seasons, and how we can measure it.

What is Indoor Humidity and How is it Measured?

Humidity is essentially the amount of moisture that is present in the air. It plays an important part in keeping us and anyone else in our homes healthy and comfortable.

The humidity within your home or any other indoor space will typically be measured in terms of relative humidity levels. This tells you how much humidity is present within your home, allowing you to take the necessary steps to reach the optimal levels based on your needs and the climate you live in.

To measure the relative humidity in your home, an instrument called a hygrometer is used. The Hygrometer measures the percentage of water vapor present in the air relative to the total amount of water that the air could hold based on its temperature.

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ThermoPro TP50 Digital Hygrometer Indoor Thermometer
ThermoPro TP50 Digital Hygrometer Indoor Thermometer
  • Humidity meter with humidity level icon indicates air condition -- DRY/COMFORT/WET
  • Updates every 10 seconds, has a tabletop stand and a magnetic back to attach to the fridge
  • Can also be as a refrigerator thermometer, freezer thermometer, reptile thermometer, soil thermometer, humidor hygrometer, cigar hygrometer, and more
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ThermoPro TP49 Digital Hygrometer Indoor Thermometer Humidity Meter
ThermoPro TP49 Digital Hygrometer Indoor Thermometer Humidity Meter
  • Face icon comfort indicator for DRY/COMFORT/WET air condition and large display numbers
  • High accuracy with refreshed updates every 10 seconds
  • Multiple mounting options: Tabletop Stand / Magnetic Back / Hanging Hole
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Two-Pack
Indoor Humidity Thermometer Hygrometer
Indoor Humidity Thermometer Hygrometer
  • 2-pack, easy to use and install digital hygrometer thermometer
  • Separate probe sensor for humidity and temperature, and 18 ultra-large sensitive vents, measuring the change per 10 seconds in real-time
  • Company offers a full refund for a worry-free purchase
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The humidity within your home is likely to be very different from the humidity levels outside. This is because there is less ventilation in indoor spaces and there is likely to be a temperature difference in the home due to air conditioning or heating systems that may be in use.

Humidity massively impacts our thermal comfort, which controls whether we feel too hot or too cold and can have dramatic effects on our overall health and wellbeing if not properly managed. It’s also true that humidity changes dramatically from season to season, as well as on a day-to-day basis.

Let’s take a look at how the relative humidity within your home may change in the hottest and coldest months and the potential impacts this might have on you and your home.

Related: What’s the Difference Between an Air Purifier and a Humidifier?

How Does Humidity Change in the Summer?

In most cases, as the temperatures rise in the summertime, so does the humidity.

Warm air is able to hold more moisture, meaning humidity levels tend to increase in the summer months. Typically, the highest humidity levels occur sometime between July and September, although this will vary depending on where you live.

Although warmer climates are generally conducive to having higher humidity levels, this isn’t always the case. If you live in a state with high temperatures but low precipitation, Nevada or Arizona, for example, you’re more likely to experience extremely low humidity levels due to the lack of moisture in the air.

The relative humidity levels in these desert states remain very low year-round. However, the general rule for most places is that higher temperatures in the summer equate to higher indoor relative humidity levels, causing the air to feel sticky and heavy. That is why it is helpful to know what the ideal indoor humidity in the summer is and try to attain it in your home.

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How Does Humidity Change in the Winter?

On the opposite end of the scale, cold weather in the winter generally brings with it much lower humidity levels.

Cold air holds substantially less moisture than warm air, making the air feel much dryer. When the cold air particles from outside enter your home the heat causes them to expand, reducing the humidity levels by siphoning any moisture out of the space.

This means that even though using heating systems will increase the temperature in your home, it won’t increase the humidity if the air outside is cold and dry.

What Happens When Humidity is Too High or Too Low?

When the relative humidity levels in your home become too low or too high, this can have detrimental effects on your comfort and overall health.

Indoor humidity that is too high can create a breeding ground for bacteria and mold spores within your home. This happens when humid air comes into contact with cooler surfaces, such as windows. This creates condensation which may then accumulate on surfaces such as walls and ceilings, leading to mold and mildew growth. Black mold is extremely dangerous and can cause numerous health issues such as allergic reactions, sinusitis, skin rashes, and breathing or lung problems.

Additionally, high humidity levels in the home can also cause damage to the infrastructure of your home, causing peeling of wooden surfaces or dampness and the emission of unpleasant odors from soft furnishings. Not to mention, the high levels of humidity are likely to leave you feeling increasingly sluggish, sweaty, and tired throughout the day, while also lowering the quality of your sleep during the night.

On the contrary, if humidity levels in the home are too low, you are likely to find that you experience increased congestion, a stuffy nose, sore throat, and dry cough. You may also have skin reactions such as eczema and itchy, flaky rashes caused by excess dryness. If the humidity levels in your home remain exceptionally low for prolonged periods of time, you might also see cracks or damage appearing within your home’s infrastructure, particularly on wooden surfaces.

Ideal Indoor Humidity in the Winter

So, how do we avoid these problems? Well, you should start by establishing the optimal humidity levels for your home. These will differ from summer to winter.

In winter, most experts recommend that indoor relative humidity levels should be kept between 30% and 40%. While you want to add moisture into the air, it’s important that levels are not increased too much to avoid the subsequent growth of mold within your home.

To regulate the humidity levels in your home during the winter, you might choose to use a humidifier. A humidifier will emit water vapor into the air, increasing the overall relative humidity levels.

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Everlasting Comfort Ultrasonic Cool Mist Humidifier
Everlasting Comfort Ultrasonic Cool Mist Humidifier
  • Ultrasonic humidifier has 1.6 gallon tank that works in rooms up to 500 sq feet and lasts for up to 50 hours
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AquaOasis™ Cool Mist Humidifier
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LEVOIT Wi-Fi Cool Mist Humidifier
LEVOIT Wi-Fi Cool Mist Humidifier
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Most high-quality humidifiers allow you to specify the desired humidity levels, making this a great, easy way to regulate your indoor humidity. There are various different types and models of humidifiers available, each with slightly different specialties, so it’s definitely worth doing a little research and shopping around before investing in one.

See our guide on the best place to put a humidifier.

Another way of increasing the humidity in your home is by adding more houseplants. While this is unlikely to make a huge amount of difference, it may add a small amount of moisture and can generally improve the overall quality of the air within your home.

You could also place water basins alongside any heating systems. The water will be evaporated and emitted into the air.

Related: The Best Whole House Air Purifier for Cleaner Air

ThermoPro TP49 Digital Hygrometer Indoor Thermometer Humidity Meter Room Thermometer with Temperature and Humidity Monitor Mini Hygrometer Thermometer ThermoPro TP49 Digital Hygrometer

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Ideal Indoor Humidity in the Summer

In the summertime, when outdoor humidity levels tend to be higher, it is recommended that indoor relative humidity levels be allowed to reach no higher than 50%. Exceeding 50% will greatly increase the chances of mold and bacteria growing within your home.

The first way you might try to decrease the humidity levels is by using an air conditioning unit or system to hit that ideal indoor humidity in the summer. By cooling the air, you remove excess moisture and decrease humidity levels. Just be sure to regularly clean out and replace any filters or pipes to prevent bacteria growth within the unit. Fans can also be used to increase circulation and ventilation and cool the air.

Alternatively, if the humidity levels in your home remain too high, you could opt to invest in a dehumidifier. A dehumidifier removes excess moisture from the air and improves the overall air quality in your home.

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Kesnos 70 Pint Dehumidifier
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hOmeLabs Dehumidifier
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  • Use in medium to large rooms and basements, up to 1,500 sq. ft
  • Energy Star
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Honeywell Energy Star DehumidifierHoneywell Energy Star Dehumidifier
  • Use in medium to large rooms
  • Energy Star qualified, various modes including auto-restart after power outage
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Much like humidifiers, there is an abundance of makes and models of dehumidifiers available, each with different functions. Choosing a model that allows you to pre-set your desired humidity levels is the best way of ensuring your home maintains a healthy level of humidity and optimal air quality year-round.

Related: Will a Dehumidifier Cool a Room?

Final Thoughts on What is the Ideal Indoor Humidity in the Summer and the Winter?

The relative humidity level within your home plays a vital part in the maintenance of a clean and comfortable space and is also directly linked to your own overall health and wellbeing.

By measuring and regulating the humidity levels in your home, you can ensure that your health and that of anyone else within your household are not at risk, regardless of the temperature outside.

Anyone who lives in an area with particularly changeable weather or adverse seasonal weather changes will know the struggles of maintaining healthy humidity levels in the home and will likely have had some experience with the negative impacts that too high or too low humidity levels can cause.

By having a good awareness of the home’s ideal indoor humidity in the summer and winter months and regulating your humidity levels accordingly, you should be able to prevent any of these adverse reactions from occurring in the future.

ImageProductOur RatingPrice
Top Choice
ThermoPro TP50 Digital Hygrometer Indoor Thermometer
ThermoPro TP50 Digital Hygrometer Indoor Thermometer
  • Humidity meter with humidity level icon indicates air condition -- DRY/COMFORT/WET
  • Updates every 10 seconds, has a tabletop stand and a magnetic back to attach to the fridge
  • Can also be as a refrigerator thermometer, freezer thermometer, reptile thermometer, soil thermometer, humidor hygrometer, cigar hygrometer, and more
9.7
Check Price on Amazon
Best Value
ThermoPro TP49 Digital Hygrometer Indoor Thermometer Humidity Meter
ThermoPro TP49 Digital Hygrometer Indoor Thermometer Humidity Meter
  • Face icon comfort indicator for DRY/COMFORT/WET air condition and large display numbers
  • High accuracy with refreshed updates every 10 seconds
  • Multiple mounting options: Tabletop Stand / Magnetic Back / Hanging Hole
9.7
Check Price on Amazon
Two-Pack
Indoor Humidity Thermometer Hygrometer
Indoor Humidity Thermometer Hygrometer
  • 2-pack, easy to use and install digital hygrometer thermometer
  • Separate probe sensor for humidity and temperature, and 18 ultra-large sensitive vents, measuring the change per 10 seconds in real-time
  • Company offers a full refund for a worry-free purchase
9.5
Check Price on Amazon

READ NEXT: Do Dehumidifiers Use a Lot of Electricity?

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