What It Means to Have Low Humidity in Your House

Having low humidity in your house can cause a number of issues that impact your health, comfort, and home. Understanding what low humidity is, why it occurs, and how to increase humidity levels is important for any homeowner. This comprehensive guide will explain everything you need to know about low humidity in your home.

What is Low Humidity?

Humidity refers to the amount of moisture in the air. It is measured as relative humidity, which is the percentage of water vapor present in the air compared to the maximum amount that could be held at a given temperature.

Low humidity occurs when the relative humidity drops below 30-40%. At these lower levels, the air is unable to hold much moisture. The air feels drier, and moisture evaporates more quickly from surfaces.

During winter months, low humidity is very common as colder outdoor air with lower moisture levels enters homes and is then heated, further reducing its relative humidity. Running heating systems dries the air even more.

Low humidity occurs more during winter months, but excessively dry air can happen at any time of year. Understanding the optimal humidity range and being aware of low humidity signs helps identify when action should be taken to increase moisture levels.

Signs of Low Humidity

There are several noticeable signs that indicate your home’s humidity may be too low:

  • Dry skin and sinuses: Low moisture in the air dries out skin, nasal passages, and airways. This can lead to itchy, flaky skin, chapped lips, dry eyes, and bloody noses.
  • Cracking wood: As wood dries out, it shrinks and can begin to crack, warp, or split. This is visible on wood floors, furniture, musical instruments, and more.
  • Static electricity: Dry air prevents static electricity from dissipating properly. This leads to more shocks, zapping, and crackling from static buildup.
  • Furniture damage: In addition to wood cracking and splitting, overly dry air can damage upholstered furniture and fabrics. It causes materials to become brittle and fray or tear more easily.
  • Peeling wallpaper: Wallpaper glue dries out faster when humidity is low. The adhesive loses tackiness, resulting in corners peeling and seams splitting.
  • Increased dust: Dust is more likely to become airborne and accumulate faster in low humidity environments. More frequent dusting is needed.

Paying attention to these common signs can clue you in to low humidity before it reaches problematic levels. It’s best to take action to boost moisture when the first symptoms appear.

What’s the Ideal Humidity Level?

The ideal indoor humidity range is 30% to 50% relative humidity. Below 30%, most people experience dryness discomforts. Above 50%, moisture issues like mold growth and condensation become more likely.

30-50% humidity is a sweet spot where air feels comfortable yet allows sufficient drying to prevent dampness problems in homes.

The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) recommends a humidity range of 30-60% as acceptable for health and comfort in residential spaces. But the narrower 30-50% zone is optimal for most homes.

Aim to keep your home’s humidity between 30% and 50% year-round. Use a hygrometer to monitor humidity, and make adjustments when levels drop too low or rise too high. Sustaining humidity in the ideal range prevents problems associated with air that is overly dry or damp.

Why Does Low Humidity Occur in Houses?

There are several reasons indoor humidity can plummet to lower than comfortable levels:

Cold, Dry Outdoor Air

In winter, bitterly cold air from outside enters homes. This frigid air holds very little moisture. When it’s heated by your home’s furnace, radiators or heat pumps, the heated air’s relative humidity drops significantly.

For example, if 0°F air containing 0.5% relative humidity is heated to 70°F, its relative humidity plunges below 5%. The large temperature increase causes moisture to decline sharply.

Home Heating Systems

Running your home’s heating system, whatever type it may be, directly reduces indoor humidity. Most heating systems add no moisture back to the air.

As air is heated, its capacity to hold moisture rises. But since no moisture is added by the heating process, the relative humidity percentage goes down.

Air Infiltration and Ventilation

Outside air inevitably enters homes through cracks around windows, doors, through foundations, etc. During colder months, this infiltration brings in drier outdoor air.

Ventilation like running bathroom and kitchen fans also removes warmer, more humid indoor air and replaces it with drier outdoor air. This exchange contributes to lower humidity.

Low Humidity Outside

In certain climates, like deserts or at high elevations, low outdoor humidity may persist year-round. When outdoor humidity is very low, it’s difficult to keep indoor levels in the ideal range.

Dry outside conditions coupled with other drying factors make sustaining sufficient indoor moisture especially challenging in these regions. Added efforts are needed.

High Thermostat Settings

The higher you set your thermostat, the more heat is applied to air. This rapidly strips moisture from the air as it warms.

Overheating homes in winter is a primary driver of extremely low indoor humidity. Keeping your thermostat at a moderate, comfortable setting helps avoid exaggerating the drying effect.

Excessive Ventilation

While some ventilation is beneficial, over-ventilating can excessively dry your indoor air. Running bathroom and kitchen fans longer than necessary replaces interior air with very dry outside air.

Leaving windows cracked for prolonged periods in cold weather also contributes too much dry air infiltration. Minimizing excessive ventilation preserves some humidity.

Dangers and Issues Caused by Low Humidity

Allowing indoor humidity to remain very low for extended periods can lead to a variety of problems affecting health, comfort, furnishings, and the home itself. Risks and effects of low humidity include:

Respiratory Problems

Prolonged exposure to dry air can irritate and inflame airways. Low moisture causes dryness and fragility in nasal passages. This makes respiratory infections more likely.

Sinus congestion and bloody noses are also common issues. Overall, low humidity exacerbates respiratory ailments like colds, flu, allergies, asthma, and bronchitis.

Dry, Itchy Skin

Skin needs sufficient moisture to stay supple and healthy. In arid conditions, skin becomes dry, leading to itchiness, flaking, cracking, and even lesions. Lotion and cream only provide temporary relief.

Dry air also prevents small wounds and cuts from healing properly. The risk of skin infections rises. Use of lotions and creams increases due to excessive dryness discomfort.

Damaged Wooden Materials

As moisture evaporates from wood, it shrinks and cracks. Low humidity causes wooden furniture, floors, musical instruments, and other items to split, warp, and crackle.

The structural integrity of wood buildings and furniture deteriorates over time in consistently arid conditions. Hardwood flooring may gape, lift, or cup.

Eye Discomfort

Dry eyes are another repercussion of low humidity. Tear film inadequately lubricates the surface of the eyes when moisture evaporates too quickly.

This leads to irritation, redness, stinging, blurred vision, and light sensitivity. Eye drops only provide temporary relief for dry eyes caused by excessively dry indoor air.

Elevated Static Electricity

Static buildup intensifies when humidity is low. This leads to more frequent static zapping and even small sparks when touching metal surfaces or electronics.

Excess static cling causes clothing, blankets, and other fabric items to stick together bothersomely. Static shocks are also annoying and prevent electronics from functioning optimally.

Increased Dust and Dander

Dust mites, pet dander, and other allergens can accumulate more rapidly when moisture is low. Dry air allows allergens to become airborne easily.

Frequent dusting is needed to control settled dust. Airborne particles also worsen allergies and asthma. Running a humidifier helps precipitate airborne allergens.

Higher Heating Costs

Heating systems run longer to maintain warmer temperatures in arid environments. The lack of moisture also makes homes feel colder at lower thermostat settings.

Combatting low humidity by turning up the heat results in much higher energy bills. Sustaining proper moisture levels reduces the urge to overheat for comfort.

Growth of Mold and Bacteria

Although low humidity does not directly cause mold, it creates an environment mold spores thrive in. Mold spreads over surfaces as they dry out.

Bacteria also proliferate faster in dry conditions. Low moisture allows harmful microbes to flourish and be disturbed more easily into the air.

How to Increase Humidity in a House

If your home’s relative humidity frequently drops below 30% or you notice dryness discomforts, taking action to increase moisture is advised. Here are ways to effectively and safely raise low humidity in houses:

Use a Humidifier

Humidifiers are designed to directly introduce water vapor into the air and raise indoor humidity. They are the most straightforward and effective solution for low humidity.

The two main types recommended for homes are warm mist and ultrasonic cool mist humidifiers. Follow the manufacturer’s guide to use the appropriate water and cleaning routine for your model.

Place portable room humidifiers in the main living spaces used most. Even better, install whole house humidifiers attached to your HVAC system to balance moisture through the entire home.

Adjust Your HVAC System

Make adjustments to the operation of your home’s heating, ventilation and air conditioning (HVAC) system to minimize effects that dry out the air:

  • Lower the thermostat to maintain a moderate temperature around 68-70°F. Overheating exacerbates low humidity.
  • Limit use of bathroom and kitchen exhaust fans to 15 minute cycles. Turn fans off promptly rather than letting them run for hours.
  • Have your HVAC system serviced to ensure it is in top working condition and circulating indoor air appropriately.
  • Consider upgrading your system’s air filter to a model containing activated carbon that helps maintain humidity.

Use Damp Rid

DampRid uses anhydrous calcium sulfate to draw moisture from the air and put it into a solid, gel-like form in a tub or on a hanger. Recharge crystals by boiling to use over and over in rooms.

Use a Dehumidifier

While dehumidifiers remove excess moisture, using one in a large open living space can pull enough humidity from other adjacent rooms to raise levels adequately.

Try operating a dehumidifier in your basement or other damp area on a low setting. Empty the tank often so some moisture redistributes to other house air.

Run an Aquarium

Keep a fish tank or aquarium to add some evaporative moisture into a room’s air naturally. The larger the water surface area, the more ambient humidity is increased.

Cook, Shower, and Do Laundry at Home

Home activities that inherently add warm moisture to the air can help counteract dryness. Cook more meals at home and take more showers or baths to temporarily boost humidity.

Running the clothes dryer, especially on a water-saving cycle, also pumps some needed moisture into indoor air.

Use a Vaporizer

Vaporizers heat and vaporize water to emit steam into the air like a humidifier. The steam saturates air with moisture and raises humidity.

Add Houseplants

Houseplants naturally transpire moisture into the surrounding air through their leaves. Having several plants in a room can add a few percentage points of humidity through this evapotranspiration.

Install Indoor Ponds or Fountains

The exposed water surface of indoor ponds, fountains, aquariums, and other water features evaporates into the air and provides natural humidification.

Use Window A/C Units

If you have a window air conditioner, use its vent setting to close the outdoor air damper while running the system fan. This circulates indoor air without bringing in more dry air.

Adjust Blinds and Curtains

Keep blinds, shades, and curtains closed so sunlight streaming in through windows doesn’t overheat and dry out interior air. Keeping curtains drawn also provides insulation.

Limit Cold Air Infiltration

Add weatherstripping around leaky doors and windows to minimize the amount of outdoor air leaking indoors. Keep doors and windows closed as much as possible.

Use a Humidifier in Your HVAC System

Installing a whole-house humidifier directly into your home’s HVAC system provides the most complete solution. The moist air can circulate evenly throughout the home.

Frequently Asked Questions About Low Humidity in Houses:

What are the health effects of low humidity?

Low humidity drying out nasal passages, skin, and airways. This leads to increased sinus congestion, dry skin, itchy eyes, bloody noses, and worsened respiratory illnesses. Germs also spread faster in dry air.

At what temperature does low humidity occur?

Low humidity can happen at any indoor temperature, but is most problematic when overheating homes in winter. Setting thermostats excessively high exacerbates low moisture. Keep temperatures moderate.

What humidity level is too low in a house?

Indoor humidity below 30% is considered too low. Air feels overly dry and moisture-related issues start developing below this level. Humidity between 30-50% is healthiest.

Why is my humidity suddenly low?

Sudden drops in indoor humidity are most often due to a change of seasons with cold, dry air moving in. Turning up your heat, using fans more, and poor weatherization allowing air infiltration can also cause sudden low moisture.

Is 15% humidity in house too low?

Yes, 15% humidity is dangerously low for an indoor environment. This severity of dryness irritates airways, drastically dries skin and nasal passages, and significantly damages furnishings. Take urgent action to raise humidity above 30%.

How can I tell if my house humidity is low without a meter?

Signs like static zaps, dry skin and sinuses, furniture damage, excessive dust, and wood cracking signal low humidity without using a meter. Paying attention to these symptoms can alert you to aridity issues.

Does low humidity affect sleep?

Yes, overly dry air resulting in congestion, coughs, sore throats, and skin irritation leads to poor sleep quality. Using a humidifier in the bedroom helps sustain comfortable moisture levels that enable better rest.

Key Takeaways: Maintenance Tips for Dealing with Low Humidity

  • Monitor indoor humidity regularly using a hygrometer. This allows you to catch low moisture issues before they intensify.
  • Use humidifiers, vaporizers, and HVAC tweaks to directly raise humidity when it drops too low. Houseplants and aquariums also help a little.
  • Limit excessive ventilation from bath fans, range hoods, and clothes dryers. Don’t over-ventilate your home.
  • Moderate your thermostat temperature. Excessive heating dries the air. Keep home around 68-70°F.
  • Have your HVAC system serviced yearly to maximize proper moisture balancing airflow. Change filters regularly.
  • Weatherstrip windows and doors to stop outside air infiltration that brings drier air inside. Keep them closed.
  • Add moisture directly to your home’s air as needed using humidifiers. Don’t let low humidity persist unchecked.


Low humidity below 30% causes a host of issues like dry skin, respiratory problems, static, and wood damage. Cold winter air, heating systems, and excessive ventilation dry out indoor air. Using hygrometers to monitor moisture, running humidifiers, and adjusting HVAC operation can effectively raise low humidity for healthier indoor conditions.

Sustaining proper humidity year-round prevents dry air discomforts and problems. With active maintenance and moisture adding solutions, you can maintain lower levels within the ideal 30-50% range for comfort and well-being.