Whole House Dehumidifiers: How They Work and How You Benefit

Whole House Dehumidifiers: How They Work and How You Benefit
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

What does it mean when we talk about dehumidifiers? We examine the types, how they work, what they do, and why they might be needed.

When we meet with homeowners who have called us, we go through a series of questions to determine what the big and small problems are with your indoor air quality. A big problem might be that a furnace has died, and you’re looking for a replacement.

A small problem - at least comparatively - is about the air quality.

See if any of these sound familiar:

  • Does your air conditioner seem to be working overtime?
  • Is your home muggy in the summer?
  • Do you suffer from allergies or have flare-ups of your asthma during the summer?

If we hear “Yeses,” we start to focus on why the air is so bad. Has it always been that way, or is it something new? And we’ll ask if you want to do something about it.

A lot of homeowners admit that the relative humidity inside is unpleasant, but either they are used to it and don’t see the need to remedy it, or they are willing to put up with the problem because they are on a tight budget.

If you’re sure that we can’t do anything about mustiness in the basement, let’s talk about dehumidifiers, both big and small. The reason we’re talking about it is that damp air can affect your wood, your indoor insects, and even your health.

Our bodies feel temperature and humidity, so if you have an 80-degree day with low humidity, it doesn’t feel bad. But if you have an 80-degree day with high humidity, it’s sticky.

Your HVAC choices can make a huge difference in your level of comfort.

Types of Dehumidifiers

Desiccant dehumidifiers

Desiccant dehumidifiers are usually used to aid in the recovery of materials that have experienced water damage, or for jobs that require a lot of humidity control. They dehumidify as air passes through a hygroscopic substance, such as calcium oxide or silica gel, that works to extract water.

It pulls humid air in one side, and desiccant soaks up the humidity. On the other side, the evaporator is expelling moisture as water vapor.

Commercial units do not have a condenser. Instead, the warm, moist air is exhausted out of the building. through ductwork. Thus, there is no condensate that forms anywhere in the system. The commercial models have a high extraction rate; they can remove up to 3,200 pints (400 gallons) of moisture per day. They are used mostly for large-scale commercial and industrial jobs, such as construction sites.

A consumer-grade desiccant dehumidifier warms humid air, which removes moisture from the desiccant. The humid air enters the condenser, where it condenses. The water then drips down into a collection bucket, much the same way as it does in a compressor-based dehumidifier.

Dehumidifier

Room Dehumidifiers

This is the compressor-based type you buy at Lowe’s and stick in your basement. It’s actually a little refrigeration circuit, and it works like an air conditioner. It’s got a condenser, an evaporator coil, and a compressor. It discharges hot air out the back.

Depending on the fan speed and the amount of air you move across the evaporator coil, it could do more cooling or more evaporation. The slower the air moves, the more it evaporates.

It’s designed to remove humidity out of one room at a time.

One drawback to room dehumidifiers is they have a pan and a container that collects water that might need to be emptied. (Some of them have a hose on them that can connect to a drain.)

Many of them don’t have a filter on them, so you need to keep an eye on the coil for mold or dust buildup.

And they’re not very efficient. They draw a lot of power.

Whole-House Dehumidifiers

As the name implies, this can treat an entire house. They can be standalone in the basement, or they can be installed into your duct system.

The Aprilaire 1850 Dehumidifier, for instance, can remove up to 11.9 gallons of water per day. The control panel can be mounted on the top or side of the unit to make it easy to access. You can adjust it so the air is more or less humid.

The Aprilaire 1850 is low maintenance with no trays to empty, and simple once-a-year filter cleaning or replacement.

It can be controlled through your thermostat. You can set it to maintain a humidity level of 50% (most literature suggests the ideal humidity is somewhere between 30% and 50%).

One of these is about as effective as ten of the room dehumidifiers.

Dehumidifier

How Does Humidity Get Into Your House?

Humid air rises. So if you’ve got humidity in the basement, it’s going to work its way up to the top floor. That’s why your attic space feels so awful in the summer: Hot air and humidity will wind up there.

Unless it has been sealed, concrete is porous. The reason your basement smells musty is water is absorbed by the basement walls, where it sits.

How often is your basement damp in the summer? For many here in Ohio, the answer is “Often.”

The relative humidity is regularly 80-90% in Central Ohio and many similar climates. Every time that door opens to the outside world, humid air will rush in.

Newer homes sometimes have a fresh-air intake, so that brings in more humidity in the summer.

Dehumidifier

How Is Excessive Indoor Humidity Harmful?

Problems associated with humidity (high or low) can include:

  • Allergies, either seasonal or due to a specific environmental trigger
  • An overly-warm upstairs or finished attic
  • Musty smell
  • Black mold or other mold growth in damp areas. Anything past about 60% relative humidity, and you’ll be at risk to develop black mold. While an ideal level can vary, 30-60% is generally a safe range to stay within.
  • Asthma issues
  • General decrease in comfort
  • Permanent window fog
  • Wild discrepancy between temperatures on different floors of the home
  • Spiders, bug infestations, and cobwebs
  • Moisture damage in floorboards
  • Water stains
  • Discomfort. Humidity is equal to heat for humans. You’ve undoubtedly seen the “heat index” temperature when checking the weather. This accounts for how humidity levels affect how we experience heat. Thus, dehumidifying isn’t just about mold or allergies. The lower the humidity, the cooler you’ll feel.

What Are the Benefits of Dehumidifiers?

Less humid air is going to help prevent mold, which loves moist places. That drier air will also cut down on the mold that might be festering in your ducts.

You will have fewer insects, which will leave spiders with less to feed on. If you can get the relative humidity below 50%, bugs will go elsewhere.

Removing excess humidity makes it feel more comfortable. In a two-story home, the upstairs is normally too warm anyway. If you pull that humidity out of there, that’s going to make it feel better.

An added benefit is that your air conditioner or heat pump isn’t going to work as hard because it doesn’t have to fight temperature and humidity.

There will be less stress on your woodwork. When moisture interacts with a hardwood floor, the side of the boards closest to the moisture expands. This expansion can be in the form of cupping (the center of the board is lower than the edges) or crowning (the center of the board is higher than the edges).

Anything made of wood will suffer, including furniture, guitars, and pianos. Some wooden floor manufacturers’ guarantees won’t cover flooring that is damaged due to excess humidity. The National Wood Flooring Association estimates that 90% of wood flooring failures relate to relative humidity and moisture problems in the home.

Waroped wood floor

There are three methods for setting up a whole-house dehumidifier:

  • Stand-alone
  • Partially-ducted
  • Fully-ducted

Why would you set up a partially ducted dehumidifier?

If you’re fully ducted, your duct system has to serve all the areas you want to be dehumidified.

Partially ducted is when you’re going to duct part of it in the basement and connect the rest into the whole home. If the basement is damp or just partially finished, that’s a good reason to have a partially-ducted whole-home dehumidifier.

If the basement is unfinished, that’s when we most likely see the dehumidifier as standalone. This can be an effective way of ridding most of your entire house of humidity. If you attack the humidity at its source - in this case, a wet basement - the humidity won’t rise up through the floors.

If you dry out that space, it kills the bugs, humid air isn’t rising upstairs anymore, your central system isn’t working as hard because it’s not having to account for all that humid air.

If your basement is fully finished and has a good venting with your central system’s supplies and returns, you can go fully-ducted. That dehumidification will go through the entire house.

How Much Do Whole-Home Dehumidifiers Cost?

Whole-home dehumidifiers tend to run between $2,000-$3,000. That price can produce some sticker shock, but it’s important to remember that your air conditioner will be working far less, potentially saving you hundreds of dollars per year with a whole-home dehumidifier installed. These can absolutely pay for themselves over time in addition to providing you with years of comfort.

Contact Us Today To Learn More

If you’re going through the estimate process with HVAC contractors, they might bring up the subject of indoor air quality products.

It’s true that some HVAC contractors will try to sell products you may not need. They can make more money by upselling. However, good HVAC contractors will base these recommendations on your individual concerns.

At Fire & Ice, we ask questions related to many air quality problems, such as allergies, humidity levels, and odors, among others. What we’re looking for are the specific issues you have in your home, and how much they affect your level of comfort.

For example, someone with an immunocompromised family member may have a “need” for a particular air purification product. In comparison, that very same product could be a “want” for your neighbor, but it’s not enough for them to justify the added cost.

You can get benefits from each of these air treatment product types for any home. Whether or not they are the right fit for you, though, is ultimately a personal decision.

Plug in your zip code on the map below to contact us today.

In the meantime, here are some related articles:

How Much Does a Heat Pump Cost to Replace in 2021?

How Much Does a New Furnace Replacement Cost in 2021?

Cost of an Air Conditioner Replacement in 2021

 

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