Dehumidifiers That Emit Carbon Dioxide And Carbon Monoxide

Carbon dioxide (CO2) and carbon monoxide (CO) are harmful gases with severe health implications. It’s important to know if any of your appliances like dehumidifiers create or emit either of them.

Most dehumidifiers do not produce carbon monoxide (CO) or carbon dioxide (CO2). However, whole-house furnace dehumidifiers can generate mild to dangerous levels of the two gases.

This article discusses the different types of dehumidifiers and explains which ones may or may not create CO2 and CO.

Types Of Dehumidifiers

It’s easier to know how the different types of dehumidifier work to understand whether or not they release CO2 and/or CO.

Dehumidifiers are appliances that remove excess moisture from the environment, bringing the relative humidity (RH) down to the ideal level (30 to 50%). How they work is mostly the same for all dehumidifiers: they draw in the air via a circulating fan. Extract moisture from it, and then send out the dry air into the room.

The three types of dehumidifiers are based on their water extraction system:

1. Desiccant Dehumidifier

Desiccant dehumidifiers use a desiccant substance (like silica) to dehumidify the air. The silica gel is present on a rotating, corrugated wheel. As the wheel rotates, the air passes through it. This is when silica extracts the moisture from it.

Around 75% of this dehumidified air (called processed air) is emitted from the unit. In contrast, 25% of the air stream (called reactivation air) is reheated within the dehumidifier.

It’s then passed through the wheel in the opposite direction. This reactivation air absorbs the moisture from the silica gel, preparing it for another dehumidification cycle.

2. Compressor (Refrigerant) Dehumidifier

Compressor dehumidifiers are the traditional units that use refrigerants and a set of coils to extract moisture from the air. They consist of a refrigerant, fan compressor, cooling coil, and reheater.

  • A rotating fan draws humid air inside the unit.
  • The compressor pressurizes the refrigerant, enabling it to extract heat and moisture from the incoming air.
  • When the removed moisture encounters the cooling coil, it condenses (due to temperature difference) and forms water vapors.
  • These vapors are collected into a reservoir (bucket).
  • Lastly, the heating coils reheat the dehumidified air. In this step, the heat initially absorbed from the original air stream is added back.
  • The unit then emits air into the room.

3. Whole House Dehumidifier

Whole house dehumidifiers are a subtype of compressor units. They use refrigerant and cooling coils, but they dehumidify the entire house instead of catering to a specific area. This extensive coverage is achieved through an elaborate duct system.

Whole house dehumidifiers are not independent machines. Instead, they are integrated with the central air conditioning or furnace of the house.

Furnace Dehumidifiers

We all know that furnaces are appliances that heat the air in a room or whole house. You can get a professional to install a whole-house dehumidifier onto the furnace. 

The furnace draws cold air into the system, filters it to remove contaminants, and then sends it to a heat exchanger. The exchanger heats the air, which is then circulated through the ducts and into the dehumidifier for moisture extraction.

Air Conditioning Dehumidifiers

Central air conditioning systems remove heat from the indoor air. In air conditioning dehumidifiers, air from the AC unit flows into the duct system and is drawn inside the dehumidifier by the fan. This air is then processed and emitted as dry air.

Which Dehumidifiers Produce CO or CO2

We have established that CO and CO2 are always a result of combustion. Desiccant and compressor dehumidifiers do not involve combustion and, therefore, do not pose a risk of CO or CO2 exposure.

However, you may experience increased levels of CO and CO2 when using whole-house dehumidifiers integrated with furnaces. Although the dehumidifier unit does not produce toxic by-products, the combustion in furnaces at the heat exchanger level can create poisonous exhaust gases, including CO and CO2.

Typically, heating appliances like furnaces do not produce dangerous levels of CO and CO2. However, internal issues like a saturated filter, undersized ductwork, or obstruction within the system, can impair the airflow, resulting in incomplete combustion. This sends the system under stress, which leads to a rapid emission of high concentrations of CO or CO2.

Plentiful Air has more information on how to stop dirty furnace filters releasing carbon monoxide available here.

Carbon Dioxide

Carbon dioxide is a naturally occurring gas that makes up 0.04% of our air. It’s colorless but has a pungent, acidic odor.

It is generally a combustion product, as carbon from fossil fuels combines with oxygen atoms in the air.

CO2 also enters the air when we exhale. In fact, humans breathe out 3 billion tonnes of carbon dioxide each year.

Other than that, cigarette smoke, fire breakouts, decomposition of materials, natural decay of organisms, weathering of rocks, heating systems, etc., are also common sources of CO2. US households produce an estimated 7.5 tons of CO2 annually.

CO2 Toxicity

If there is high levels of CO2 in the air, more than an average amount of CO2 is inhaled. This CO2 takes up most of our lung capacity, leading to low oxygen levels in our body.

Oxygen is needed to synthesize energy, which is then used to carry out vital functions. So, oxygen deprivation results in low energy, and can ultimately lead to major organs like the brain and heart to stop working.

We can go into respiratory arrest if oxygen levels are not restored immediately.

Side Effects

Here are some of the common health side effects of CO2:

  • Drowsiness
  • Headache
  • Flushing (redness of the skin)
  • Disorientation
  • Hyperventilation
  • Respiratory distress
  • Difficulty breathing

More than 40,000 ppm of CO2 can immediately lead to death.

People with pre-existing cardiovascular disorders, anemia, or respiratory conditions like asthma and emphysema are at significant risk of severe health issues due to CO2 exposure.

Carbon Monoxide

Known as a silent killer, carbon monoxide or CO is a colorless and odorless gas that claims more than 400 American lives annually. It is produced from incomplete thermal combustion; thus, exhaust fumes from trucks, cars, lanterns, fireplaces, construction materials, and furnaces are common sources of CO in homes.

Usually, 100 ppb (0.1 ppm) of CO exists in Earth’s atmosphere.

CO Poisoning

Exposure to 70 ppm or more of CO can lead to various health complications. This is because hemoglobin or Hb (the red blood cell’s protein that binds oxygen and supplies it around the body) has a 250 times higher affinity for CO, which means it prefers carbon monoxide over oxygen.

When air concentrated with CO is inhaled, CO molecules displace oxygen in the body. These low levels of oxygen in the body cause severe energy depletion.

This leads to impairment and, eventually, death of vital organs like the brain and heart.

Side Effects

Here is a series of symptoms caused by CO poisoning:

  • Nausea
  • Fatigue
  • Miscarriage
  • Disorientation
  • Irreversible anorexic brain injury due to severed oxygen supply
  • Ischemia (reduced blood flow)
  • Heart failure

Pregnant women, infants, the elderly, and immunocompromised individuals are at significant risk of worsening health upon CO exposure.

CO levels above 150-200 ppm can prove lethal.

Carbon monoxide and carbon dioxide are not the only gases you should be worried about. Plentiful Air has more information on which dehumidifiers produce ozone, a toxic gas, available here.

How To Test For Carbon Monoxide In Your Home

Carbon monoxide (CO) monitors are often installed in homes to detect possible leaks. Other than that, signs like soot stains, the smell of exhaust gases, and the sudden onset of CO poisoning symptoms indicate CO leak.

Carbon Monoxide Monitor

Carbon monoxide monitors have a silicon chip that electrically charges a CO sensor. This sensor is highly sensitive to CO and rings an alarm upon detecting the gas. In the case of low concentrations like 50 ppm, the alarm can take a few hours to go off. But, if the exposure is too high a level of the gas, the alarm alerts within minutes.

Easy installation, long battery life, and interconnectivity are essential for a suitable device. Considering this, if you’re looking for a CO detector for your home, we recommend the Google Nest Protect – a smoke and CO detector that warns you immediately when the gas is detected. In case of danger, the Split Spectrum Sensor indicates the original area of gas leaks or fire breakouts.

Google compatibility enables you to control the monitor via your smart devices. It also has multiple cool features like a night light and battery indicator, as well as versatile controls that make this detector a great choice.

Signs Of A Leak

Carbon monoxide is called a silent killer because it is colorless and odorless, so it isn’t easy to notice its rising concentration in the house. However, a CO leak almost invariably presents with the following signs:

  • Onset Of CO Poisoning: Nausea, headache, dizziness, and confusion are the initial symptoms of CO exposure. If everyone around in and around the house simultaneously starts showing these signs, you should suspect a gas leak.
  • Soot Stains: In case of incomplete combustion, yellow or black powdery soot stains are found around the appliance (ex: furnace dehumidifier).
  • Smell Of Exhaust Gases: CO leak is not isolated. Instead, the appliance also emits various exhaust gases along with CO. The odor of these fumes is distinctly noticeable and is an indication of a potential CO leak.

If you notice any of these signs, immediately evacuate the area, and consult a physician for a checkup and required medical intervention.

How to Test for Carbon Dioxide in the Air

Carbon dioxide detectors are the best way to test carbon dioxide levels at home. Other than that, the characteristic sharp and acidic odor of the gas, accompanied by the onset of signs like headache, dizziness, and shortness of breath, are indicators of high CO2 concentration.

We recommend investing in the Simbow CO2 Monitor. This is a lightweight, compact device that accurately displays not only CO2 levels but also air quality index (AQI), temperature, and relative humidity. It comes with versatile touch controls that you can easily adjust.

Using this device, you can conveniently track indoor air conditions, and then use compatible equipment (like air purifier for AQI, humidifier or dehumidifier for low and high RH respectively) to improve to a healthy level.

Frequently Asked Questions

Can a Dehumidifier Set Off a Carbon Monoxide Detector?

Whole-house dehumidifiers integrated with furnaces can set off carbon monoxide detectors. Apart from the normal heating process in the furnace, technical issues like obstruction in the system or exhaust flue, undersized or oversized ductwork, saturated filter, etc., can create high levels of CO. 

Does Humidity Affect Carbon Monoxide Levels?

Carbon monoxide (CO) levels are independent of humidity, which means humidity does not affect it.

Theresa Orr

Theresa Orr holds a PhD in Earth Science and specializes in determining past climates from rocks using geochemistry. Her passion for clean water, soil and air drives her to provide easy to understand information for everyone to read.

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