What is the Ideal Indoor Humidity for My Home and Business?

ideal indoor humidity

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Did you know that Americans spend around 90% of their time indoors?

That’s right!

Now, you may think that this is the best way to avoid exposure to air pollution. Unfortunately, this isn’t always the case, as the air inside homes could be up to five times more polluted.

What’s more, the air inside your home could either be drier or more humid than outside air. Both could lead to not only discomfort but also increased safety and health risks.

That’s why you need to ensure that your home maintains ideal indoor humidity levels at all times.

The question now is, what exactly is the ideal humidity range, and what could happen if you don’t meet this?

We’ll answer all these questions in this post, so be sure to read until the end!

What Is Humidity?

Humidity is the measurement of water vapor present in the air. Water vapor, on the other hand, is the invisible, gaseous form of water. Water vapor is the biggest player in the greenhouse effect, accounting for around 60% of it on average.

The more water vapor in the air, the more “humid” and “oppressive” the air will feel like. The less water vapor there is, the drier the air will also be. In both cases, however, it can affect not only how comfortable you’ll feel, but also your health.

Absolute vs Relative Humidity

Divide the amount of water vapor by the mass of dry air at a certain temperature, and you get “absolute humidity”. Remember, the higher the temperature, the more water the air can contain. You’ll find absolute humidity expressed as g/m3 (grams of moisture per cubic meter).

You’ll hear the term “relative humidity” more often, though, especially in weather news. This term refers to the “percentage” of water vapor in the air relative to how much water the air can hold. The higher the RH is, the greater the likelihood of raining.

That’s because the higher the relative humidity is, the more saturated the air becomes. So, if the RH reaches 100%, it means that the air is completely saturated that it can’t hold any more water vapor.

What’s the Ideal Indoor Humidity Level Then?

Scientists recommend keeping indoor humidity levels at 40% to 60%. The EPA, on the other hand, recommends maintaining indoor humidity at 30% to 50%.

That said, you should aim for a humidity level that doesn’t go beyond 60%.

The thing is, South Carolina’s relative humidity levels range from around 67% to 79%. It’s often lowest during February, while it’s most humid during August. Either way, these higher-than-ideal humidity levels are due to SC’s humid subtropical climate.

Your home’s indoor humidity level could go even higher if you have improper ventilation. Ventilation is key to removing excess moisture in the air inside your home. This moisture can come from cooking, showering, cleaning, or drying your laundry inside.

Whereas, too low humidity levels can occur if your air conditioner is set too low. This can also happen if your AC is malfunctioning and drawing in too much air. In both cases, the AC will pull out too much air (along with the water vapor) from inside your home.

Dry air may also occur if you use excessive dehumidifiers.

What Can Happen If Indoor Humidity Goes up Too High?

During hot days, your body keeps its core temperature at optimal levels by sweating. As you sweat, the air helps your body get rid of sweat by evaporating it.

This can only happen if the air still has “space” to accommodate extra moisture. So, if it’s really humid, the air will have a hard time evaporating your sweat.

In short, high levels of humidity prevent the body from sweating effectively. This, in turn, reduces your body’s ability to keep your core temperature normal. As a result, you may experience overheating, and in more serious cases, a heat stroke.

Heat-related illnesses are common in the US, with over 320,000 cases requiring ED visits from 2006 to 2010. Of these, 38,392 of the affected required hospitalization. Almost three in four patients suffered heat exhaustion, while 5.4% had a heat stroke.

What’s more, researchers found that most humidity-related illnesses occur inside homes.

Some studies also suggest that high humidity can affect mood and sleep quality. Others also found potential connections between high humidity and exacerbated health symptoms.

What If It Drops Too Low?

Low relative humidity can make you feel cooler than it actually is. That’s because the air still has space for more water vapor, so it can still evaporate your sweat.

Sounds awesome, right?

Not always. For one, if the humidity level is too low, it can cause respiratory-related problems. The cold can also aggravate asthma and allergy symptoms. The symptoms could be worse in people who already have compromised lung functions.

Dry air may also irritate and dry the respiratory tract’s mucosal lining. This may then result in respiratory and skin infections. These problems could get worse if your home has too many indoor air pollutants, such as dust and pet dander.

Some viruses, such as the influenza virus RNA, also thrive in low relative humidity levels.

Effective Humidity Control Measures to Follow at Home

The good news about indoor humidity is that it’s easy to control. Here are a few ways that you can keep moisture levels inside your home within the ideal range.

Get Those Air Conditioner Leaks Fixed ASAP

Air conditioner leaks are serious HVAC issues that increase indoor humidity levels. A coolant leak is even more dangerous, as it can cause refrigerant poisoning.

If you notice pooled liquid beneath the AC, check the condensate line and drain pan. It’s possible that there’s a build-up in the line, forcing the water back into your home. You may also have a severely corroded drain pan that’s causing the leak.

A broken condensate pump, on the other hand, already requires repair or a replacement. In this case, be sure to contact your local HVAC technicians ASAP.

Run (and Maintain) Your Exhaust Fans

Turn the kitchen and bathroom exhaust fans every time you cook, wash the dishes, or take a shower. Make sure that nothing blocks the vents and that they’re free of dust and debris.

Invest in Dehumidifiers

With SC’s humidity hovering above 65% on average, a dehumidifier is a good investment. If you can, get a whole-house unit. Otherwise, you may also buy a portable one for your kitchen, bathroom, and other more humid areas in the house.

Keep Your Home’s Indoor Humidity Level in Check

Now that you know how humidity can affect your health, it’s time to keep it in check. So long as you follow our tips, you can achieve ideal indoor humidity levels at home.

Do you have a faulty HVAC system that’s contributing to higher moisture levels at home? If so, know that we can help! Connect with us now so we can get those leaks and other issues fixed ASAP!

John Daner
John Daner

HVAC Technician with 12+ years experience in the field.