Understanding Condensation & Humidity

Understanding Condensation and Humidity

Moisture damage is an issue threatening homes on a variety of different levels. Learn the basics of how moisture manifests within a home, and how homeowners or contractors can combat its effects.

Condensation: What Is It?

Moisture impacts every facet of your home’s HVAC systems. Whether it’s sealing, insulation, or ventilation, moisture and its subsequent effects play a part in all three systems’ effectiveness. Let’s take a look at all the ways moisture can impact a home’s systems and comfort levels.

In the same way a glass of cold water gathers condensation, so too does a home. Condensation is most commonly used to refer to the stage in the water cycle in which molecules change from the gaseous form to the liquid form. As air cools, it loses its capacity to hold water vapor, and those molecules are left behind on solid surfaces.

In the home, condensation is most commonly found in the form of fog or ice, often on window panes, glass, vents, or pipes. Effectively every location within a home which comes into contact with water or water vapor is bound to experience some level of condensation.

What Condensation Does

The primary issue that results from condensation occurring is the formation of water droplets in isolated locations throughout the home. Water damage and mold are the most common consequences of excessive condensation, and the impact and speed at which these consequences manifest is dependent on the environment the moisture appears in.

Where Condensation Occurs In A Home



Washer / Dryer Rooms

Under Sinks

Vents / Radiators

Door Frames

Condensation Prevention

Preventing condensation will save homeowners substantial sums in the longterm. Even better, the prevention methods are not complicated. Here’s some easy ways to keep condensation from causing excessive damage in a home.

  • Keep indoor temperature as consistent as possible
  • Open windows when creating steam (showers, hot water from sink)
  • Do not dry clothes indoors or over radiators/fans
  • Inspect your washer/dryer for good ventilation
  • Use exhaust fans in rooms with water flow
  • Double check the health of exhaust fans
  • Do not use/strictly manage humidifiers
  • Use ceiling/portable fans to keep air current circulating
  • Remove excess plants from windowsills


A home’s humidity level is the amount of water vapor which exists in the air of the home. Many people are familiar with what humidity feels like, but are less aware of the consequences a humid home environment creates. Even then, it can be difficult to tell that your home is too humid once your body acclimates to the feeling.

Humidity and condensation are interconnected components of a home’s indoor air quality. While condensation is the physical manifestation of water droplets on specific items, humidity is the state of the air before condensation happens. The two share many of the same qualities, side effects, and locations of origin throughout a house.

Finding A Temperature Balance

Humidity is often described as a negative trait of air, but it’s actually necessary for optimal home comfort. Too little humidity results in dry air, which has its own host of related problems, including difficulty breathing, skin irritation, and an overall colder “feel” of the house.

At the same time, high humidity leads to higher condensation and its associated effects. On top of that, homes with high humidity levels are susceptible to paint peeling, mold and rot, and a lovely environment for pests like cockroaches and termites.

As such, homes have to find a proper balance of humidity in the air. Thankfully, many home temperature control measures allow for humidity measurement and management. Most thermostats are equipped with scales or metrics for humidity control.

In addition to thermostats, humidifiers and dehumidifiers are excellent for small scale adjustments of humidity levels. These devices are widely available at hardware stores and online, and are excellent for moisture-prone areas that aren’t as affected by moisture management efforts from the rest of the home. Basements, attics, crawl spaces and garages are all perfect locations to incorporate a humidifier or a dehumidifier if needed.

Recommended Humidity Levels

The ideal amount of humidity is going to vary from person to person and from household to household. However, there is a general scale which can be used to help homeowners determine just how much air moisture they need to exist in a comfortable home environment.

Outdoor Temperature (F°)Indoor Humidity Level
> 50°No more than 50%
>20°No more than 40%
10 -20°No more than 35%
0 -10°No more than 30%
-10° - 0°No more than 25%
-20° - -10°No more than 20%
<-20°No more than 15%