How a Humidifier Works (benefits and various types)

How a Humidifier Works (benefits and various types)
Roger Bakies
Residential Sales Professional

I have been in the residential/light commercial HVAC business for 30 years. I grew up in a sheet metal fabrication shop and have installed, serviced, sold and helped people choose new systems to best fit their needs and lifestyle. I look forward to helping you pick the best fit for your home!

About This Article

A whole-home humidifier works in conjunction with your furnace. It adds moisture to the circulated air, and is especially useful in the winter months, when the relative humidity outside drops below 30%. Its use has health benefits as well as house benefits.

How Does a Humidifier Work?

Homeowners in the market for HVAC products are generally thinking only about heating and cooling, a replacement perhaps for their aging air conditioner or furnace. They’re not thinking about overall comfort concerns, and they are rarely thinking about humidity.

This is why we sit down with every potential customer and make a list of what we call “comfort concerns.” A lot of times, you’ll be experiencing one or more of the humidity-related problems we’ll discuss in this article. But it’s rare to find someone who realizes that these problems can be solved with an HVAC solution.

We don’t care if you’re in Central Ohio, which happens to be our service area, or live elsewhere. It’s essential that you should be working with someone who is trying to be proactive about managing your home’s comfort -- not just someone who wants to sell you a system as quickly as possible.

Whole-House Humidifiers

In this article, we’re going to talk about one aspect of comfort, and how you can improve it: Whole-house humidifiers that work in conjunction with your furnace or heat pump can make your house more comfortable year round, especially in the winter.

Let’s talk about dry air, and why it can be in your house.

Forced air heat tends to dry out your home, plus, in the wintertime, the relative humidity inside naturally drops as the temperature outside goes down. Cold air doesn’t hold water very well. It’s common for relative humidity to dip below 30%. And as you’re going inside from out, and vice versa, that dry air will find its way inside your house somehow or another.

If the outside temperature is 32 degrees Fahrenheit, the maximum amount of water that a cubic meter of air can hold is 5 grams. Now you bring this cubic meter of air inside and heat it to 25 degrees C or 77 degrees F. The relative humidity is only 23 percent.

What’s the Best Home Humidity Level?

According to the CDC, the healthy zone is approximately 30-60% relative humidity. The relative humidity in your home, even here in central Ohio, can reach as low as 15% in the winter. For comparison, the average relative humidity of the Sahara Desert is 25%.

Humidity can cause problems if it gets too low inside your house. That dry air is not friendly.

Problems Caused by Low Humidity:

  1. Dry Wood. Cracking floorboards and wooden infrastructure of your home.
  2. Illnesses. Low humidity is a good environment for many bacteria and viruses to exist. It’s a big part of the reason flu season hits over the winter in most parts of the country. respiratory infections increase a lot when it’s too dry.
  3. Skin and Throat. Dry, cracked skin and a sore throat are hallmarks of the colder winter months.
  4. Cold Spots in Home. This could be due to the power of your furnace system, your ductwork, or drafty windows. But often, it’s related to humidity.
  5. Dust. The lower the humidity, the dustier things are, because moisture quells dust.
  6. Paint. Paint can dry out, creating cracks. Dry air can even cause paint to flake and peel from walls.
  7. Cold and Flu viruses. Studies have shown that many viruses stay alive in the air much longer at humidity levels below about 40%. In fact, this is true of the coronavirus that wreaked havoc in 2020

It can even cause structural issues within your home. Some wooden floor manufacturers will provide warranties for their work only if the home has a whole-home humidifying system.

Whole-Home Humidifiers: A Solution to Dry Air

Humidifiers simply put moisture back into the air, and by doing that, it raises your comfort level and protects your investment in your home.

Whole-Home Humidifiers

I’ve been in a lot of people’s homes where the people tell me “This existing humidifier doesn’t cut it, it doesn’t provide enough humidity.” They are usually talking about a room humidifier, one that is portable and can work in only one space at a time.

A ducted, whole-home humidifier is a much better solution to dry air. Some homes do fine in the winter, but if you experience any of the issues listed above, you’ll benefit greatly from a whole-home humidifier.

To determine whether a humidifier would be a good addition to your home, check out the video below or the following article that breaks down the benefits, the different types of humidifiers, and the costs.

RELATED: Can HVAC Protect From Coronavirus and Other Illnesses

When is a Whole-Home Humidifier Unnecessary?

  1. If you live near a large body of water, say the ocean, you will have plenty of humidity both outside and inside your home
  2. If you live in a place that’s constantly muggy - say Florida - you won’t need a humidifier there.
  3. If your home is insulated well, doesn’t have a basement, and never seems to have high-humidity days. You’re already good to go.

How Much Does a Whole-House Humidifier Cost?

Costs can vary, but a couple of rules tend to hold true:

  1. The larger your home, the more powerful your humidifier will need to be, affecting cost.
  2. It’s generally cheaper to have a humidifier installed at the time of a full HVAC system replacement. You’ll save on labor costs and may also be able to take advantage of company incentives for pairing equipment and services.
  3. The cost of a ducted humidifier is a substantial initial investment, but if it stays in the home for even 5-10 years, it’s making that money back in utility costs. These can save you hundreds of dollars on heating and cooling costs per year.
  4. Humidifiers can start as low as about $600, but vary significantly depending on the size of your home.
  5. A power humidifier is about $750 - $775.
  6. A steam humidifier is over a thousand, maybe $1250.

Those prices include installation costs.

Mobile humidifiers - or room humidifiers - will cost less and can be useful for specific situations. But they will never be able to service an entire home, or even a meaningful portion of it.

Could you buy a single-room humidifier for, say, your bedroom? Yes, and it will help when you’re in that room, but it won’t do anything about the systemic, house-wide problems caused by low relative humidity. However, mobile units are your only whole-home humidification option if you have radiant or ductless heat.

A technician installing a humidifier.

The Three Types of Whole-House Humidifiers

There are three different types of humidifiers commonly used in a residential home.

1. Bypass Humidifier

The bypass humidifier is a square box that mounts on the side of your ductwork, and it has an evaporator panel. There’s one moving part on a bypass humidifier: the solenoid valve opens when the fan is running on the furnace.

Water trickles across the evaporator panel, and there is a 6-inch pipe that brings air from the supply duct around through the humidifier. It takes the water across the evaporator panel and pulls it back into the return duct.

Simply put, water is boiled, which turns it into steam, which is then injected into the air stream.

Bypass humidifiers typically need to drain their water supply. So if you don’t have a floor drain, you can always have a drainless bypass humidifier installed. These reuse their water supply, meaning that they use less water.

2. Power Humidifier

The power humidifier (also known as a fan-powered humidifier) is roughly the same thing as the bypass. It has the evaporator panel in it, and the solenoid valve opens and lets the water through the evaporator panel. But it has its own fan built in, as opposed to the bypass humidifier.

It pulls air from the ductwork through the evaporator panel right back into the same duct. Power humidifiers are able to produce up to a gallon more of humidity per day compared to bypass humidifiers.

3. Steam Humidifier

The other humidifier used in residential homes is the stream humidifier. It plugs into the wall and literally turns water into steam. This does use a fair amount of electricity.

Which humidifier is most effective?

Any of these units is effective. Making the best choice among the three depends on the size of your home, your budget, and your desired level of comfort.

Fire & Ice sells and installs Aprilaire products because they are the most effective and trouble free.

What capacity do the various types provide?

The bypass humidifier is good for up to a 3000 square foot home, and the power humidifier might go up to 4000. The steam humidifier has the largest capability.

How long do whole house humidifiers last?

Whole house humidifiers typically last around 5-10 years. I’ve seen humidifiers that are 15-20 years old that work just fine.

The biggest problem they can have is that the evaporator panel starts leaking, and water runs alongside the ductwork, leaving the ductwork rusted and water on the floor.

It's a humidifier, not a de-humidifier

People confuse those all the time. I ask if they have a humidifier, and they say “Oh, yeah. I’ve got a humidifier in the basement, it’s plugged in, and I’ve got to empty the pan.” Well…that’s a dehumidifier. It will take moisture out of the air, but doesn’t add it.

Like the room humidifier, it works well for a small space, but doesn’t begin to address the overall comfort of your home.

Health benefits from a whole-house humidifier

As we mentioned before, air-conditioned air can dry out your sinuses, nasal passages, and throat when you sleep, leading to inflammation and swelling in these sensitive tissues. Using a humidifier while you sleep in the summer helps alleviate these symptoms of dry air, as well as seasonal allergies.

Your Next Steps

The easiest way to find your comfort zone is to ask the right questions. What questions are those? Some of them will be particular to your home and budget, but I can give you a head start with good general questions. Our HVAC Contractor Checklist was made for exactly this purpose: to get you the information you need to make the right decision for your home.

HVAC isn’t just about the bottom line. It’s about creating a home environment where you can enjoy your life.

That’s what we’re here for at Fire & Ice.

The only way to know the exact cost of an air conditioner replacement is to schedule an in-home estimate with an experienced professional. But when you know factors that affect the cost, you can ask more informed questions and make a better-informed decision when the time comes.

As you begin to schedule estimates, here’s what we believe an in-home estimate should look like.

And if you’re ready to discuss options specific to your home, we’d love to sit down with you.

At Fire & Ice, “Your Trust Is Our Business”. To us, this includes providing the knowledge you need to make an informed decision. We have the team to help you determine the right product for you, your home and your budget.

If you live in Central Ohio, click the button below to schedule your free in-home estimate today!

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