Does a Humidifier Clean the Air? Everything You Need to Know

smart humidifier and air purifierBreathing dry air can cause respiratory ailments, including asthma, bronchitis, sinusitis and nosebleeds.

According to family medicine physician, Dr. Daniel Allan of the Cleveland Clinic, when your sinuses dry out, the mucus that usually traps microorganisms thins out. The result? You’re left with little to no protection from harmful organisms. 

“Cold winter air is one of the main causes of these issues because it holds very little moisture,” Dr. Allan continues. “Since the humidity during the cold weather is low, the little moisture around is quickly sucked up into the air. As a result, moisture evaporates quickly from our bodies, drying out the skin and nasal membranes.”

Do I Need an Air Humidifier?

Most of the above problems can be solved with improved indoor humidification. A humidifier adds much-needed moisture to the air in the home until a healthy balance is achieved. At the recommended relative humidity, the surrounding air is humid enough that it doesn’t need to suck moisture from skin and membranes. 

If you’re still undecided about whether a humidifier would be a wise investment, consider the following points. If you have any of the issues listed below, then you absolutely need a humidifier for sinus problems;

  • You have colds from November to March 

Over the past few years, have you observed that you or a family member experience cold-like symptoms around November through March? These signs often include a sore, itchy throat, runny nose, and dry eyes. If so, low humidity could be the cause. 

  • Dry skin and scalp 

Dry skin care concept banner with place for text

Dry air draws moisture from wherever it can, including the furniture in the house to your pets and even yourself. In humans, this often results in dry, scaly skin and scalp.

In many cases, you’ll use moisturizers with little success. The only solution to such problems is improved humidification. 

  • You have asthma or related respiratory complications

There are two reasons low humidity is bad for people with asthma and other respiratory ailments. First, dry air causes the nasal membranes to dry and thin out. And thinner membranes mean a weakened barrier for disease-causing microorganisms. 

Secondly, whenever you turn up the thermostat in your home, the heating system kicks up clouds of dust, pollen, and other allergens. Consequently, you need optimal indoor humidity to protect yourself the potential health issues that may be caused by these elements. 

  • You’re using a furnace constantly

Finally, drawing from the above point, if you use the heater a lot, it would also be wise to buy a humidifier. The first reason as suggested above is that fan systems in heaters awaken and blow allergens throughout the home. The other reason is that the electric heaters we love so much produce dry heat. In the winter, this dry heat will absorb even the little moisture in your indoor air. Replenishing your indoor humidity using a humidifier is the only way to solve this dry indoor air problem. 

Types of Humidifiers

Humidifiers can be categorized by mode of operation or by size. With regard to the method of operation, there are five types of humidifiers. These are central, evaporative, impeller, steam, and ultrasonic.

  • Central humidifiers

Central humidifiers are built directly into the home heating, ventilation, and air conditioning (HVAC) system. Often, they are installed on the return air duct. That way, the moisture is released to the room together with the heat from the furnace. The humidifiers draw the required water from the home’s main supply and they can easily humidify an entire home.

  • Evaporative humidifiers

Evaporative humidifiers are some of the most common. They blow water through a moistened wick filter. As the water passes through the wick filter, it’s broken down into tiny moisture particles. Fans then blow the moisture particles out of the humidifier unit and into the intended space. 

  • Impeller humidifiers 

Impeller humidifiers have rotating discs that help to break down water into moisture particles. These discs rotate at very high speeds. However, they’re built into the humidifier unit thus pose no risk of injury to users. Impeller humidifiers are less expensive than other humidifier types.

  • Steam vaporizers

Consumers sometimes confuse evaporative humidifiers with vaporizers. The main difference between the two is that vaporizer humidifiers involve boiling water until it turns into vapour. The vapour is then dispersed into the room. Blower fans aren’t needed as the heat energy is sufficient to push the warm moisture throughout the room. 

  • Ultrasonic humidifiers 

Ultrasonic humidifier in the house

Finally, ultrasonic humidifiers depend on an ultrasonic vibration to break down water into moisture particles. Ultrasonic humidifiers are some of the least expensive and produce the finest mist. They work excellently even in small spaces and kids’ bedrooms. 

Categorization by Size

When it comes to size, there are whole-house, console, and personal units. Whole-house humidifiers are the most powerful. They are designed for entire houses. Console units, meanwhile, are moderately sized thus suited for medium rooms. Finally, personal humidifiers are tiny units designed to serve the small area around an individual. Bottled water humidifiers and travel models are excellent examples of personal humidifiers. 

Cool vs. Warm Mist Humidifiers

Finally, humidifiers can also be cool mist or warm mist. The difference here is the temperature of the moisture released to the room. Cool-mist humidifiers release cool/cold moisture while warm mist models deliver warm humidity. Most ultrasonic and impeller humidifiers are cool mist. Steam vaporizers, meanwhile, are warm-mist models. 

How to Measure Humidity

humidistat vs hygrometerBefore you go into measuring humidity, it’s essential to understand the different types of moisture. There are three broad types of humidity; absolute, relative, and specific.

  • Absolute humidity

Absolute humidity, measured in grams of water vapour per cubic meter of air (g/m3), is a measure of the amount of water vapour in the air, irrespective of temperature or air pressure. When the amount of water vapour in the air rises, the absolute humidity increases even if the temperatures remain the same. 

  • Relative humidity 

Relative humidity, however, is the actual amount of water vapour in the air in relation to how much water vapour that particular volume of air can carry. As such, relative humidity is often affected by temperature and air pressure, among other factors. Unlike absolute humidity, relative humidity is expressed as a percentage such as 60% or 40%. 

  • Specific humidity 

Quite similar to absolute humidity, specific humidity refers to the weight of water vapour contained in a unit amount of air. Unlike absolute humidity, however, specific humidity is expressed in grams (of water vapour) per kilogram (of air). 

The Measuring Process

When we talk about humidity in the home, we’re talking about relative humidity. Therefore, we’ll be discussing how to measure relative humidity. 

The device used to measure relative humidity is called a hygrometer. The simplest hygrometer is a sling psychrometer. A sling psychrometer consists of two thermometers mounted together with a handle attached to a chain. Of the two thermometers, one is ordinary while the other has a cloth wick over its bulb (thus known as a wet-bulb thermometer).

As water molecules evaporate from the wet cloth’s surface, the particles take some heat with them, resulting in a lower temperature reading. Generally, at 100% relative humidity, no water would evaporate from the cloth. As such, the readings from the two thermometers remain the same. However, as relative humidity drops, the reading on the wet-bulb thermometer begins to change. Comparing the changes in the two thermometers allows experts to determine relative humidity. 

Today’s hygrometers are much more advanced. Mechanical hygrometers, for instance, use organic material (often human hair). As the material expands and contracts as a result of increased or reduced humidity in the air, the hygrometer records the readings and uses it to determine relative humidity. In modern hygrometers, the readings are displayed on a digital screen. 

Most humidifiers have built-in hygrometers. Some, however, require that you separately purchase and install a wall-mounted hygrometer. The recommended relative humidity is 30-50%.

Humidifier and Allergies  

health effects of indoor air pollutionSo, you might be wondering how humidifiers help with allergies. Do the humidifiers kill allergens? Or do they prevent microorganisms from entering our homes? 

Well, we can say it’s both. Although humidifiers don’t contain chemicals that directly kill allergens and other microorganisms, they help create conditions that make it impossible for them to survive. 

There are a variety of indoor allergens that can trigger symptoms during the winter, especially if you end up spending a lot of time indoors owing to the poor weather. These include dust mites, pet dander, mould, and cockroach droppings. 

  • Dust mite: Dust mite is commonly found in bedding, furniture, and carpets. They live in warm, damp environments, and their poop and dead bodies can get into household dust. Heating during the cold winter season is one of the main triggers of the mite.
  • Pet dander: Pet dander is found on almost any indoor surface including beds, carpets, and upholstery. The dander mostly comes from pets and dogs and mixes up with dust.
  • Mould: Mold is mostly caused by damp weather. Signs include dark, moist areas in the bathroom, basement, and under sinks. 

Sneezing is usually the first sign of allergies during the cold weather. Itchy eyes are also a familiar symptom as well as a runny nose. You may also experience;

  • An itchy throat
  • Itchy ears
  • Skin rashes
  • Feeling sick
  • Difficulty breathing 

These symptoms will quickly subside and soon go away once you raise the humidity in your home to 30-50%. Otherwise, the problem could worsen, resulting in;

  • Chest tightness
  • Wheezing/whistling 
  • Feeling exhausted 
  • Feeling anxious 

It is therefore vital to properly humidify your home to prevent or relieve the symptoms before the situation worsens. 

Is It Allergies or Cold?

It’s also important to differentiate between allergies and cold. Allergies triggered by dry winter conditions often cause cold-like symptoms. However, allergies don’t cause cold. You’ll know you have a cold if you experience;

  • Symptoms that last up to two weeks
  • Symptoms during warmer seasons
  • Body aches and fever
  • Sore throat 

Colds also don’t cause itchy eyes. Therefore, if you have itchy eyes, it’s likely to be allergies. Humidification can help relieve several flu symptoms such as a runny nose and stuffiness. However, you need medical treatment for the other cold symptoms. 

Humidifiers vs. Air Purifiers

This is a common debate among humidifier shoppers. Would it be better to invest in a humidifier or should you buy an air purifier instead?

Unfortunately, there’s no straightforward answer. In certain situations, a humidifier would be the ideal solution. In others, an air purifier would be the better alternative. The most important thing is to understand what each appliance does.

  • Humidifiers 

Humidifiers add valuable moisture to indoor air. However, they don’t remove dirt/dust particles from the air. The primary purpose of an air humidifier, therefore, isn’t to clean air but to add moisture to it. 

You should buy a humidifier if you have symptoms of dry air such as allergic reactions, dry skin, and asthma. It would also be wise to invest in a humidifier during seasons when you intend to run the furnace continuously. Heat tends to absorb indoor moisture. Humidifiers can help replace the lost moisture. 

Aside from the above reasons, humidification is also recommended in seasons or regions where dry air may cause floors and furniture to crack.

  • Air purifiers

 Air purifiers are different. They don’t add moisture to the air. Instead, they remove impurities from indoor air. These often include dust, pet dander, and other forms of dirt. By so doing, air purifiers protect us from these harmful elements. You should, therefore, buy an air purifier if your chief concern is dirt particles in your indoor air.

There are two broad categories of air purifiers, i.e. those that use mechanical filters and those that rely on electrostatic forces to trap electrically charged particles. Mechanical filters can remove 99.97% of airborne particles. 

So, humidifier or air purifier, or both?

Well, you no longer have to choose one or the other. If you have both humidity and dirty air issues in your home, you can buy both a humidifier and an air purifier. Or, even better, you can choose an appliance that humidifiers as well as purifies the air, popularly known as combo units. 

Wrap Up

Humidifiers are a vital appliance in achieving home comfort. They improve indoor humidity by gently and consistently adding moisture to your rooms. As such, they play an essential role in protecting you and your family from health risks of winter weather such as dry skin, itchy nasal membranes (throat and nose), and allergic reactions. Budget allowing, don’t hesitate to buy the best one for your family. 



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Melanie Mavery is an aspiring HVAC technician who is fascinated by the trends and opportunities in the HVAC industry. She spends most of her day writing content on home improvement topics and outreaching to prospects.  She's always looking for ways to support HVACs!