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What Should Humidity Be in a House With Air Conditioning?


The common word that’s always associated with air conditioners is humidity level. It’s the amount of water vapor present in the atmosphere, whether it’s indoors or outdoors. Humid environments are always described as high-temperature places because the amount of moisture in the air is also high.

While it’s part of the natural cycle of our ecosystem, there is a limit to how much humidity an area should ideally have. This case is especially true for highly populated ones, like a city, or simply inside our home. Otherwise, we can’t function properly due to the excessive amount of moisture in the air. In this case, we usually invest in cooling devices, such as an aircon, to lower the temperature of a specific area.

But is humidity a bad thing? How can it affect our daily activities? And what should be the humidity in a house with an air conditioning system?

What is Humidity?


As previously mentioned, humidity refers to the amount of moisture or water vapor in the atmosphere. It’s dependent on the level of temperature an area has. Places that experience high-temperature climate is a humid environment. This means that tropical countries have high humidity levels.

This also determines the rate at which precipitation may occur. General science tells us that an area with a high level of precipitation will most likely experience rainy seasons. Too much moisture in the atmosphere means that it needs to release the accumulated water vapor in the form of rain. Additionally, it can be measured in two ways. These are absolute humidity and relative humidity, and each can be used to describe how humid your house is.

Regardless of the current indoor temperature, absolute humidity determines how much water steam is present in the air. The accumulation of water steam is divided by the accumulation of dry air to calculate the absolute humidity of a given volume of air.

Relative humidity measures the actual amount of water steam in the air as opposed to the maximum amount that could possibly be present at that temperature.

How Can Humidity Affect My Daily Activities?

Naturally, too much of everything is not always good. While it’s recommended to have moisture in the air, as it protects our skin from being thoroughly damaged from sunlight, too much of it can cause some serious health problems.

When there is a lot of moisture in the air, as there is in humid weather, sweat does not have a chance to evaporate, making us feel hot and sticky. Our bodies must work even harder to cool off. As a result, there is excessive sweating, accelerated blood circulation both superficially and deeply, and accelerated respiration.

The human body can suffer from high moisture levels. It can make you feel tired and low on energy because the air feels warmer than the official, recorded temperature. Additionally, in environments with high humidity, hyperthermia, or overheating because of your body’s inability to effectively release heat, can have a negative impact on your health. This is the reason why we sometimes run out of breath immediately after doing minor chores.

In addition, too much moisture can also promote the growth of mold and fungus inside our house.

What is the Ideal Indoor Humidity and How Does it Circulate Inside the House?

The Environmental Protection Agency (EPA) recommends keeping indoor humidity levels below 60% relative humidity, ideally between 30% and 50%. Anything higher than this can cause a potential risk to your health.

The moisture level can also vary depending on the climate. It’s more apparent during the summer season, but during the rainy season, the relative humidity is also high. Because of evaporation during rain, the relative humidity will rise. It’s possible that water vapor isn’t entirely present in the air where the rain is falling.

However, because the air is constantly absorbing water, the humidity will rise the longer it rains. This is also the reason why we sometimes feel too hot, sticky, and sweaty despite it raining outside the house.

Moisture also moves around the house via air infiltration and vapor diffusion. Air infiltration is how outside moisture enters our home via gaps, holes, and other potential entrances.

On the other hand, water molecules diffuse through materials to cause vapor diffusion. When the temperature and moisture content is higher in one place, moisture tends to move there. Unless caused by high vapor pressure, such as rain-soaked brick veneer heated by the sun on a hot, humid day, the amount of moisture diffused is typically quite small.

How Can I Measure the Humidity in the House?

If you’re curious about the moisture level of your house, you can measure it by using a hygrometer. It’s a device that uses two thermometers — one dry thermometer and one wet thermometer — to measure humidity by evaporation. The wet-bulb thermometer is wrapped in a wetted cloth at its enlarged end.

These days, you can even buy hygrometer apps for your smartphone. However, for these apps to function, you’ll need a smartphone with a built-in humidity sensor or a standalone sensor that you can connect to via USB cable or Bluetooth.

How Does an Air Conditioner Help Maintain a Stable Humidity Level?

The HVAC coil of the air conditioner works to lower moisture levels by condensing excess water vapor into liquid and then draining it. This system provides efficient dehumidification in most circumstances with proper unit sizing and installation. It can keep the ideal moisture level below 60%.

The truth is that air conditioners do much more than just circulate cool air. They also filter, ventilate, and eliminate excess moisture. Condensation caused by air conditioners lowers humidity levels. The result of moisture condensing on windows is the same as this.

Final Thoughts


Understanding the humidity level of your place is a great advantage in keeping our home fresh and cool. It will also help us understand the reason why, sometimes, we feel sweaty and sticky, despite staying in an air-conditioned room or during a rainy season.

Additionally, it will keep us healthy and safe from the potential health risk brought by a humid season. It will give us an idea of what cooling methods we can implement inside our house to ensure a comfortable indoor experience.

JP Reyes

JP has been in the aircon industry for almost as long as he has been alive. As a child JP would help his tatay fix aircon units at their junk shop in Cavite. After graduating UP in the early 2000's, JP then started his own Aircon servicing business and within 5 years had 10 shops in 8 different cities. Fast forward to today and JP brings all his experience and expertise online to give readers trustworthy advice and reviews about Air-conditioning buying, servicing, cleaning and repair in the Philippines.

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