Indoor Humidity: How To Test Humidity In Your Home

The humidity level inside of your home can be crucial. Too much or too little moisture in the air you breathe can have a profound impact on our daily lives, influencing our comfort, health, and even the condition of our homes. As we spend a significant portion of our lives indoors, understanding and maintaining the right levels of humidity becomes essential.
In this article, we will cover what humidity levels can do to you and your home, how to test humidity in your home, and ways to increase or decrease the humidity when required.
From the basics of humidity measurement to the health and comfort effects of imbalanced humidity, we will equip you with the knowledge to create an ideal indoor environment.
Basics of Indoor Humidity
Indoor humidity is a fundamental aspect of our living environment, and to understand it better, we need to start with the basics.
Humidity, in simple terms, refers to the amount of moisture or water vapor present in the air. It is typically expressed as a percentage, known as relative humidity (RH), which represents the ratio of the current water vapor content to the maximum amount of water vapor the air can hold at a specific temperature. This percentage tells us how “saturated” the air is with moisture.
Relative Humidity vs. Absolute Humidity
- Relative Humidity (RH): As mentioned earlier, relative humidity is the most common way to express humidity levels. It tells us how close the air is to reaching its saturation point. For instance, if the relative humidity is 50%, it means the air is holding half the moisture it could potentially hold at that temperature.
- Absolute Humidity: Absolute humidity, on the other hand, represents the actual amount of water vapor in a given volume of air, typically measured in grams per cubic meter (g/m³). While relative humidity gives us a percentage, absolute humidity provides a precise measure of moisture content. It’s a useful metric in various scientific and engineering applications.
Ideal Indoor Humidity Levels
Maintaining the right indoor humidity levels is crucial for our comfort and health. The ideal indoor relative humidity levels typically range between 30% and 60%. Here’s a breakdown of these levels:
- Low Humidity (Below 30% RH): When indoor humidity falls below 30%, the air becomes dry and can lead to various discomforts. Skin can become dry and itchy, and you might experience respiratory issues like a scratchy throat or nasal congestion. Low humidity can also cause static electricity and damage wooden furniture or flooring.
- Moderate Humidity (30% to 50% RH): This range is generally considered ideal for indoor comfort and health. It prevents the air from becoming too dry or too humid, offering a balance that minimizes health risks and maintains a pleasant living environment.
- High Humidity (Above 60% RH): High indoor humidity levels can lead to a host of problems, including mold and mildew growth, which can negatively affect your health and damage your home. High humidity can also make the air feel warmer, contributing to discomfort and higher energy bills.
Effects of Humidity on Your Health, Comfort & Home
Humidity isn’t just a number on a weather report; it plays a significant role in shaping our well-being and the condition of our homes. Understanding the effects of humidity is important for creating a healthy and comfortable indoor environment.
High Humidity: Problems and Risks
- Mold and Mildew Growth: When indoor humidity levels are consistently high, especially above 60% relative humidity, your home can become a breeding ground for mold and mildew. You may notice condensation on the insides of windows. Mold and mildew can not only damage your walls, ceilings, and floors but can also have severe health implications, including respiratory issues and allergies.
- Health Issues: High humidity can lead to discomfort and health problems. It can exacerbate respiratory conditions like asthma and allergies, as the increased moisture in the air creates a favorable environment for dust mites and other allergens to thrive.
Low Humidity: Problems and Risks
- Dry Skin and Eyes: During the colder months, when indoor heating systems are running, humidity levels often drop significantly. This can result in dry, itchy skin and irritated eyes. These discomforts can be particularly troublesome for individuals with sensitive skin or preexisting skin conditions.
- Respiratory Discomfort: Low humidity can lead to dry and irritated nasal passages and throat, making you more susceptible to respiratory infections. It can also worsen existing respiratory conditions like bronchitis and sinusitis.
- Damage to Your Home: Low humidity can cause timber to crack, split, and warp. This can lead to damage to furniture and possible structural damage
The Importance of Maintaining a Balanced Humidity Level
Maintaining an ideal humidity level in your home is not just about comfort; it’s about safeguarding your health and protecting your property. By striking the right balance, you can:
- Enhance Comfort: The ideal humidity range, typically between 30% and 60%, ensures a comfortable indoor environment year-round. It prevents that sticky feeling during hot summers and alleviates dryness during the winter.
- Preserve Your Home: Maintaining proper humidity levels can extend the lifespan of your home’s structural elements, furniture, and possessions. It helps prevent warping, cracking, and deterioration.
- Safeguard Health: By keeping humidity within the ideal range, you reduce the risk of respiratory issues and allergies. You also discourage the growth of mold, mildew, and dust mites, which can trigger health problems.
How To Test Humidity In Your Home
Testing the humidity levels in your home is a crucial step in ensuring that you maintain a healthy and comfortable indoor environment. Fortunately, there are various methods available for testing humidity, ranging from simple DIY techniques to more advanced tools like hygrometers.
Hygrometers: Types and Usage
Hygrometers are specialized instruments designed for measuring humidity accurately. There are two primary types:
- Analog Hygrometers: These are traditional, analog devices with a dial or needle that indicates humidity levels. They are easy to use and can be found in hardware stores.
- Digital Hygrometers: Digital hygrometers provide precise humidity readings on a digital display. They often come with additional features like temperature readings and memory functions. Many modern thermostats also have built-in digital hygrometers.
Indoor hygrometers are available in various sizes and designs at your local hardware store or online. There are also many different types of hygrometers, including digital and analog versions. A simple hygrometer will cost you approximately $25 or less but will be well worth the investment for the health of your home and family.
To use a hygrometer, simply place it in the room or area you want to measure and wait for it to display the humidity level. Make sure to follow the manufacturer’s instructions for calibration and maintenance.
DIY Humidity Tests
If you don’t have a hygrometer on hand, you can perform some simple DIY tests to get a rough estimate of the humidity:
- Observations Made Within Your Home: One of the best and easiest ways of how to test the humidity in your house is through observation. You just simply have to pay attention to the conditions inside your home and make note of changes. If the humidity levels are too far to one end of the spectrum, you should be able to tell.
- If windows or mirrors are covered in moisture and closets have mold on the walls, those are clues that the humidity is too high.
- The humidity is too low if you see evidence of cracking plaster or wood, static electricity forming from walking across a rug, or you find yourself refilling flower vases frequently.
- The Hair Test: Human hair responds to humidity. Place a strand of hair in a small, sealed container with a damp cloth or sponge. If the hair lengthens, humidity is low; if it curls, humidity is high.
- The Ice Cube Test: This is how to test humidity without a hygrometer. Put ice and water into a glass, stir it, then leave the glass sitting alone in the room for about three minutes. After this time, there should be some moisture on the glass. If there is no moisture on the glass, you will know the humidity is low. If excessive amounts of moisture form on the outside of the glass, your indoor humidity is likely high. This is how to test humidity in a room, but should not be used as a test in the bathroom or kitchen as both of those places produce their own moisture.
Where to Place Hygrometers for Accurate Readings
To get the most accurate humidity readings, it’s essential to place your hygrometer in the right locations within your home:
- Living Areas: Put a hygrometer in commonly used rooms like the living room or bedroom to ensure you’re comfortable where you spend the most time.
- Basements and Attics: These areas are prone to humidity problems. Placing a hygrometer here can help you identify and address issues promptly.
- Near Problem Areas: If you’ve noticed specific humidity-related issues, such as mold growth in a bathroom, place a hygrometer in that area to monitor the situation closely.
Ideal Humidity Levels for Different Seasons
Indoor humidity is not a static concept; it varies with the changing seasons and outdoor weather conditions. To maintain a consistently comfortable and healthy indoor environment throughout the year, it’s crucial to understand the ideal humidity levels for different seasons.
Summer: Managing Humidity During Hot and Humid Weather
During the summer months, outdoor air tends to be warm and humid. To maintain comfort and prevent problems like mold growth, aim for indoor relative humidity levels between 30% and 50%. High outdoor humidity can infiltrate your home, making it feel muggy and uncomfortable. It can also lead to condensation on windows and potential mold issues.
Tips on how to control humidity in summer:
- Use Dehumidifiers: Portable or whole-house dehumidifiers can help remove excess moisture from the air.
- Proper Ventilation: Ensure good airflow through your home to minimize humidity buildup.
- Air Conditioning: Running your air conditioner not only cools the air but also dehumidifies it.
Winter: Combatting Dry Indoor Air
In contrast to summer, winter air is typically dry, both indoors and outdoors. Aim for indoor relative humidity levels between 30% and 40% to maintain comfort and minimize dryness. Dry indoor air can lead to various discomforts, including dry skin, cracked lips, and respiratory irritation. It can also cause damage to wooden furniture and flooring.
Tips on how to control humidity in winter:
- Use Humidifiers: Portable or whole-house humidifiers can add moisture to the air.
- Seal Leaks: Proper insulation and sealing gaps in windows and doors can help maintain indoor humidity levels.
- Avoid Overheating: Overheating your home can exacerbate dryness. Keep your thermostat at a comfortable but not excessively high temperature.
How To Control Indoor Humidity
There are a few simple things you can do to bring the humidity level in your home back to within a safe and comfortable range. The methods differ slightly from low humidity to high humidity.
How To Increase Humidity Levels
- Humidifiers: In the winter, when indoor heating systems can lead to dry air, humidifiers come to the rescue. These devices add moisture to the air, making it more comfortable and reducing the risk of dry skin, respiratory discomfort, and damage to your home’s wooden elements. Use a humidifier in the room(s) or area where the humidity level is low. Humidifiers come in various sizes and are rated based on the amount of space they can service. You could also have a whole-house or furnace humidifier system installed and only use it during colder and/or drier times of the year.
- Houseplants and Natural Methods: Another way to increase humidity in your home is by doing this naturally. You can place shallow dishes of water in several places around your home. As the water evaporates, moisture will be added to the air. Leaving the bathroom door open following a shower or opening the dishwasher after it has completed a load also adds moisture to the air. Houseplants are not only aesthetically pleasing but also natural humidifiers. The moisture they release through transpiration can help increase humidity levels in small spaces.
How To Decrease Humidity Levels
- Ventilation and Air Circulation: Ventilation will help move excess moisture out of the home from various sources ranging from washing machines, clothes dryers, and showers. You can help ventilate by opening windows, using exhaust fans or humidity control systems, and increasing air circulation just by keeping doors open throughout the home.
- Dehumidifiers: When dealing with excessively high humidity levels, especially during hot and humid summer months, dehumidifiers become your best allies. It essentially does the opposite of a humidifier by pulling moisture out of the air and collecting it as water in a removable pail or container, or draining it away via a hose. These units come in various sizes and are rated by the volume of water they can collect in 24 hours. Click here for information on choosing the right dehumidifier.
- Air Conditioners: You can also use your air conditioner more often to help regulate humidity levels. Although we don’t want to use our A/Cs continuously due to energy prices, it is important to note that using the A/C will draw moisture out of the air and result in humidity levels decreasing.
Additional Resources
To further your understanding of indoor humidity and its management, we recommend exploring the following resources and references:
- Hygrometer Recommendations:
- The Best Indoor Hygrometer Options: provides a comprehensive guide to choosing the right indoor hygrometer for your needs.
- Mold Control Tips:
- A Brief Guide to Mold, Moisture and Your Home: The U.S. Environmental Protection Agency offers practical tips on reducing mold and moisture in your home.
- Humidity-Related Health Information:
- Indoor Air Quality and Health: The EPA’s resources on indoor air quality and its impact on health.
- Home Maintenance and HVAC Information:
- Humidifier Maintenance Checklist: HVAC.com provides guidance on keeping your humidifier in top condition.
- HVAC and Humidity Control: The U.S. Department of Energy’s information on how HVAC systems affect humidity.
In Conclusion
The normal humidity inside a house should be between 30% and 50% RH. When the levels are beyond this range, the conditions can be problematic for both you and your home.
Indoor humidity is not a trivial matter; it’s a pivotal factor that can affect the quality of your life and the condition of your home. Whether it’s battling the oppressive heat and humidity of summer or the dry chill of winter, the ability to maintain optimal humidity levels can make a world of difference.
Understanding the ideal humidity levels for different seasons enables you to adapt and create a year-round haven of comfort. Summer or winter, you now have the tools to strike the right balance and ensure your indoor environment remains ideal.
There are simple ways for how to test humidity in your home and to rectify the situation. By keeping the humidity in your home within the safe and comfortable range, you will be able to enjoy and protect your home all year round.