why is my upstairs so humid

Why is my upstairs so humid? Well, as you go up the stairs, do you wonder why a clammy embrace covers you from all corners?

Does it feel like a persistent mist is around you?

If the air feels dense and you notice your living space is slowly turning into an oppressive sauna, you have high humidity levels.

But, you may be wondering, “Why is the upstairs of my house so humid?” Well, it could be due to many reasons.

Higher humidity upstairs can result from various factors, including poor insulation, climatic conditions, an inadequate HVAC system, and everyday activities within the living space.

Why Is My Upstairs So Humid?

reasons for humid upstairs

It is typical for the upper levels of a residence to exhibit a humidity level that is approximately 1% to 5% greater than that of the lower levels.

If the indoor humidity surpasses 5%, it is possible that you are encountering issues related to humidity.

It is important to check the humidity levels in different parts of your home to know the difference. But what is considered normal?

SeasonHealthy Humidity Range
Summer40% to 60%
Winter30% to 50%

So many factors play a big role in raising the humidity levels in your home, and especially in the upper portion.

For instance: 

Poor Ventilation

poor ventilation

Insufficient airflow and inadequate ventilation systems can lead to negative consequences in the upper levels of a home, as a result of poor ventilation.

In situations where air circulation is restricted, moisture builds up, resulting in increased levels of humidity. The accumulation of moisture can lead to various adverse outcomes.

You may develop mold and mildew in the home, which can cause health issues and compromise the building’s structural stability. 

How to Handle the Situation?

how to handle the situation

To tackle this problem, it is crucial to incorporate effective ventilation techniques like:

  • Installing exhaust fans
  • Enhancing natural airflow through windows or vents
  • Contemplating mechanical ventilation systems like air purifiers or dehumidifiers

Implementing these strategies aids in preserving ideal moisture levels and enhancing the quality of the air indoors, resulting in a healthier and more pleasant living environment

Inefficient Insulation

inefficient insulation

Insufficient insulation in the walls or ceilings of a home may lead to the movement of warm, damp air from lower areas to higher levels.

In instances where there are openings or insufficient insulation materials, air movement becomes unrestricted.

This promotes the infiltration of moisture-laden air into the higher regions of the dwelling. 

How to Handle the Situation?

proper insulation

It is essential to ensure proper insulation, while also sealing any existing gaps or cracks.

Achieving this is possible by utilizing different types of insulation materials, including:

  • Fiberglass
  • Spray foam
  • Rigid foam boards

Furthermore, the use of vapor barriers can aid in the prevention of moisture migration and improve the effectiveness of insulation.

Through the implementation of efficient insulation techniques, the infiltration of heated, damp air can be minimized.

And this decreases the likelihood of elevated humidity levels in the higher levels of the residence.

Fact: Inefficient insulation can pose a significant challenge in hot weather or regions with excessive humidity. 

Leaks or Water Damage

Leaks or water damage in the upper floors of a residence can greatly affect the moisture levels.

There are several elements that can contribute to this problem, such as roof leaks, plumbing issues, and condensation caused by pipes or appliances.

Water seeps into the upper areas through roof leaks, resulting in the accumulation of moisture and subsequent rise in humidity levels

How to Handle the Situation?

promptly detect leaks

 To fix the issue, you can do a number of things.

It is essential to:

  • Promptly detect leaks
  • Fix any leakage issues
  • Mend impaired roofing
  • Guarantee adequate insulation around pipes and appliances

You have to incorporate strategies that reduce water infiltration, as this will help correct the humidity issues upstairs in your home.

Fact: Plumbing problems like leaks or drips can result in water entering the higher floors, leading to a favorable condition for increased humidity. 

Inadequate or Malfunctioning HVAC System

inadequate or malfunctioning hvac system

A deficient or malfunctioning HVAC system may lead to elevated humidity levels in the upper floors of a residence.

In the event that the system is inadequately sized, it might encounter difficulties in efficiently reducing the humidity levels in those specific regions.

Conversely, a malfunctioning HVAC system, like a defective compressor or a refrigerant leakage, may impede the dehumidification procedure.

This also results in pushing the humidity levels up. 

How to Handle the Situation?

hvac system

To prevent the issue, you need to ensure that the HVAC system can handle your distinct requirements of the higher floor.  

Similarly, it is crucial to perform routine maintenance and prompt repairs to guarantee optimal system performance, which includes effective dehumidification.

Furthermore, you can use auxiliary dehumidification devices or adopt zoning systems that enable the autonomous regulation of moisture levels in distinct regions. 

Daily Activities

daily activities

Engaging in everyday tasks can release a significant amount of moisture into the atmosphere, resulting in elevated levels of humidity.

When these events predominantly take place in the higher levels of a residence, the effect on moisture levels can be more noticeable.

The process of cooking releases steam and moisture from liquids, whereas showers produce steam and humidity by utilizing hot water.

Furthermore, if clothes are dried indoors without adequate ventilation, it can lead to the accumulation of moisture.

Occupant BehaviorImpact on Humidity Levels
Cooking with inadequate ventilationHumidity goes up due to steam
Frequent showeringHumidity goes up due to increased moisture
Drying clothes indoorHumidity goes up due to water evaporation
Use of humidifiersHumidity goes up due to increased moisture
Using exhaust fansHumidity comes down by removing moisture
Regularly opening windowsHumidity comes down by expelling moist air

How to Handle the Situation?

ventilation systems

It is important to guarantee sufficient airflow in locations where these tasks occur.

This can be achieved by:

  • Employing ventilation systems
  • Allowing fresh air to enter through the windows
  • Using dehumidifying devices

Having adequate ventilation is crucial for eliminating excessive moisture.

This, in turn helps maintain ideal humidity levels and prevents potential problems linked to elevated humidity, like the growth of mold and personal discomfort.

Fact: Leaky ductwork is often the main reason you notice higher humidity levels upstairs. 

Climate and Outdoor Conditions

climate and outdoor conditions

The indoor humidity levels of a house, including the upper floors, can be greatly affected by the climate and outdoor conditions in a particular area.

Residing in a moist climate or encountering elevated levels of humidity outdoors establishes an advantageous setting for the infiltration of moisture.

Excessive outdoor moisture has the ability to infiltrate the structure’s outer layer through:

  • Openings
  • Crevices
  • Inadequately insulated sections

The accumulation of moisture can cause the humidity levels to rise. Also, the stack effect has a role to play. 

In this phenomenon, the heated air ascends and generates variances in pressure within a structure.

It has the potential to aid in the transfer of moist air from lower to higher floors. 

How to Handle the Situation?

Identify any air leaks

You can try a number of things to correct issues related to climatic conditions.

For instance, you can do the following as a start:

  • Be sure to incorporate adequate insulation
  • Identify any air leaks and seal them off as quickly as possible
  • Invest in dehumidification systems during challenging weather conditions

Implementing these strategies aids in reducing the influence of external moisture levels and fosters a pleasant and regulated indoor atmosphere across the entirety of the residence. 

Air Leaks and Drafts

Air leaks and drafts within a residence have the potential to increase moisture levels, especially on the upper floors.

Unlocked windows, doors, and openings in the building structure provide opportunities for moist outdoor air to infiltrate the residence.

air leaks and drafts

As the air seeps in, it carries along moisture, thereby elevating the overall indoor humidity levels.

It happens when heated air ascends and exits through higher-level openings while simultaneously pulling air from lower areas. 

How to Handle the Situation?

To deal with issues related to air leaks and drafts, it is essential to detect and seal all gaps in the structure’s outer shell by utilizing weatherstripping, caulk, or insulation.

By implementing this, you can effectively establish a home that is tightly sealed and properly insulated.

seal all gaps

This results in a decrease in the penetration of moist external air and the consistent maintenance of desired levels of humidity in your house.

Fact: Implementing air sealing techniques like applying weatherstrips to windows and doors can additionally deter undesired airflow and reduce variations in humidity levels. 


Why is my upstairs so humid? You may notice elevated humidity levels in your home due to many different factors.

Some of the most common issues include poor insulation, inadequate ventilation, a leaky attic, or a faulty air conditioning system.

Be sure to check the humidity levels in different areas of your home to notice the difference and then take appropriate measures to resolve the issue.