One of the key factors that many people miss when they think about efficient heating and cooling is the humidity level in their homes. When the moisture levels are high, we tend to feel hotter and the air feels sticky. If the moisture levels are too low, we experience dry skin, itchy eyes, and throat irritation. So, we need to find and maintain the optimal humidity level to keep our indoor spaces comfortable. In this article, we will take a closer look at how humidity affects a home and the optimal levels.

A Brief Humidity Primer

If you’re not concerned with the wider humidity ramifications and you just want a comfortable humidity level, stick with 30-50%. Many experts agree that this is the comfortable range for human beings and at these levels, the humidity will not cause damage to your home. Season changes can affect the humidity level, but if you stay below 50% you will be far more comfortable at any time of the year.

How Can I Measure Indoor Humidity?

To measure the humidity in your home, you will need a small and inexpensive tool known as a digital hygrometer. This is placed in spaces away from kitchens or bathrooms where moisture is generated. To get an accurate reading place the hygrometer away from doors and windows to prevent skewed results from sunlight, rain, and other external conditions. The hygrometer will give you an accurate reading of the indoor temperature and the humidity level. If the reading is outside the 30-50% comfort zone, you can confirm your suspicions that you have a high or low humidity problem.

What is Relative Humidity?

This is an often misunderstood term, but it’s pretty simple to grasp. Relative humidity is the volume of water in the air compared to the volume of water that the air can hold at any given temperature. So, if you have a relative humidity of 50%, the indoor air is holding around half of the moisture that it potentially could at that temperature.

How Can I Reduce Humidity?

To reduce the humidity level, you’ll need to reduce the volume of moisture in the indoor air. This is what a dehumidifier is designed for and there are a wide variety of models to handle different room sizes. It’s also important to change the air filter in your HVAC system and schedule an annual inspection before every heating and cooling season.

How Can I Increase Humidity?

If your home is very dry, it is possible to increase the humidity to comfortable levels with a humidifier or a portable humidifier unit. A whole-house system is a great investment for people living in drier climates because it improves the humidity in every room at once.

What are the Optimal Humidity Levels by Temperature?

As the seasons change the outdoor temperatures will fluctuate and this will affect the relative indoor humidity levels as follows:

  • Below –20ºF: 15-20%.
  • -20ºF to 0ºF: 20-30%.
  • 0ºF to 25ºF: 30-40%.
  • 25ºF to 50ºF: 40%.
  • Over 50ºF: 45%.

To keep the relative humidity at a comfortable level, the best solution is a whole-house dehumidifier or humidifier system. These are integrated into your HVAC system and the settings are adjusted automatically for optimal indoor comfort.

What are the Negative Consequences?

We briefly covered this in the introduction, but If you have an indoor humidity that’s outside the 30-50% range you will experience a variety of problems. Let’s take a look at the consequences of high and low humidity levels in more detail:

High Humidity Problems

Higher humidity levels make the air feel muggy and hotter. It can be difficult to breathe and the first people to notice this are those with pre-existing allergies and respiratory diseases. Humid air can trigger asthma attacks and allergic reactions. Excessive moisture levels can encourage mold growth and release of mold spores that degrade the indoor air quality (IAQ). The moisture may seep into the drywall, flooring, and subflooring leading to extensive damage. You may notice condensation on walls and windows and the home is likely to feel damp and unpleasant.

Low Humidity Problems

When the humidity levels are lower than 30%, the air feels dry and this causes dry eyes, throat soreness, and itchy skin problems. The symptoms of asthma and other allergies are worsened and cold and flu viruses tend to spread faster. Some people are more prone to sinus infections, chapped lips, and a dry air passageway that makes breathing painful. Dry air may even damage wood surfaces causing cracks and warping that can be expensive to replace or repair. Many people turn up the heat to keep their homes warm because the humidity has stripped the moisture from their skin which drives up the energy bills.

2 Humidity FAQs Answered

1.   What Causes High Humidity?

The most common causes are drying clothes indoors, boiling water, showering, and other activities that add moisture to the indoor air. The external weather conditions can also contribute to the problem if the insulation in the home is insufficient. If your home is affected by humidity extremes, it’s time to contact an HVAC specialist to inspect the insulation and ventilation.

2.   What is the Recommended Humidity Level?

Most experts agree that a 30-50% humidity level is optimal for indoor comfort. But, the EPA recommends that this humidity range is kept in this range to prevent the growth of mildew and mold.

What is the Solution?

If you have indoor humidity level issues, it’s easy to feel despondent because it can be hard to get the situation under control. Getting the insulation checked and clearing any ventilation blockages in the bathrooms and kitchen will certainly help. Many people manage their humidity with one or more portable units that they use in areas they are currently using. These units are relatively inexpensive, but moving them from room to room can be a real hassle. The best option is a whole-house system that can track the humidity and the effect on indoor comfort levels automatically.

If you’re concerned about the humidity in your home, contact your local heating and cooling specialist.