What is an Air Duct?
An air duct is a passage that is installed for the purpose of heating, ventilation, or air condition. Along with these functions, an air duct is responsible for supplying fresh air to a room or building, as well as pulling out the old air. This can be referred to as an air exchange or also as an air change. Depending on what type of the room, a certain number of air changes per hour (ACPH) are generally recommended. For classrooms, the number of ACPH is 4, for basement parking lots the number of ACPH is 15-30, and for commercial kitchens, 15-30 is recommended. There are many other types of rooms that have recommended air exchange rates. The minimum number of air exchanges per hour that is recommended in any type of room is 4 exchanges per hour. If the number is less than that, the air quality can be adversely affected, and people may notice health impacts. Air ducts also will attribute to creating a comfortable indoor environment and will help control the overall indoor air quality. Air ducts can be made using multiple types of material. They can be made of duct board, which is a fiberglass board that is normally covered with aluminum foil around the outside. The fiberglass is used as an insulator and the aluminon foil is to create a vapor barrier. Air ducts are also commonly made from metal duct which is sheet metal that is composed of galvanized steel. This type of air duct can be insulated using either fiberglass or it can be wrapped around the outside of the duct itself. Additionally, air ducts can be made of flex duct. Flex duct generally consists of a metal coil surrounded by plastic. Fiberglass is used to insulate it. Most ductwork is installed out of sight. Many times it is located inside of walls or within the ceiling. The most visible part of an air duct is the vent which can be located on walls, ceilings, and the floor.
History of the Air Duct:
Air ducts have been around for a long time, but not in the same manner that they are today. The first type of air duct wasn’t really an air duct at all, but rather a chimney. The Greeks began using chimneys during the 7th century to allow them to stay warm within their homes, without filling the whole home with smoke. Around 300 B.C. the Romans began to develop and use a form of central heating. They used vertical tubes underneath their floor to help heat to travel into a room. The tubes moved warm air that was initially generated from a wood furnace. Fast forward to the Renaissance and people began to use steam to go through pipes to heat rooms. In late 1700’s, James Watt developed the first central steam-based heating system. In 1919, Albert March discovered a filament which is the filament wire that is used for toasting bread. After these developments, Alice Parker patented the first actual central heating system. During the year 1935, a group of scientists combined ducts to allow them to use both heating and air conditioning. As far as cooling goes, starting in 1758, Benjamin Franklin realized that alcohol evaporating was able to cool water. Then in 1840, a physician believed that keeping people cool was the key to avoiding disease. He created a machine that held ice and used a compressor to blow air. According to energy.gov, this development laid the foundation for the creation of modern air condition. His creation leads to the development of a device in 1902 that blew air over cold coils to keep a room cooler within a business. The decide was created by Willis Carrier and was designed to help cool a printing plant. It was designed to not only cool the plant but to also control the humidity within the plant. Then in 1930 Freon was invented and produced to be used in current air conditioners as well as refrigerators.
Types of Duct
There are two main types of air ducts. The first type of duct is called a flexible duct. This duct is generally cheaper and easier to install. They are lightweight, which is why they are easier to install. It is commonly used when constructing new buildings and buildings that are undergoing renovation. These ducts will be made with flexible plastic and coils that will be surrounded with a 2-ply, polymer plastic. Since they are made of coils, the number of bends within the duct can greatly impact the performance of the duct. This type of design causes them to be ideal for tight spaces and places that are difficult to build or work in. The other general type of ductwork is rigid duct. Rigid ducts can be made up of fiberglass, fiberboard and sheet metal. Rigid ducts are more sturdy and durable and will last longer than flexible ducts. Being rigid causes them to only be used in certain types of buildings. They can be rather difficult to install, especially if it is in a small space. Sheet metal is the most commonly used rigid duct and is also the most durable of the 3 types of rigid ducts. These ducts can vary in shape and be round, rectangular, or oval. Since they are so rigid, they have a smaller chance of accumulating mold compared to other types of ductwork. Fiberboard is the next time of rigid duct and it well insulated. They have a foil that is on the outside which serves the function of being a barrier against water vapor. They are also quite inexpensive. Fiberglass lined air ducts is the other type of rigid duct. They are made of sheet metal but are lined with fiberglass. The fiberglass lining to protect the air duct from heat loss and condensation, but this makes them very difficult to clean, due to the sealed lining.
When and How to Have Air Ducts Cleaned:
You should consider having your air ducts cleaned for many different reasons. The first reason you should consider having your air duct cleaned is if there is visible mold growth inside or coming from your air duct and or heating and cooling system. Even if you’re not sure if the substance is mold, you should still have a licensed professional come look at your duct. Any time of biological growth should be shown to a professional. Next, if there is any indication that there are insects or rodents living within are near your air ducts, you should have a professional inspect them. Last, if there are excessive amounts of dust or debris that are being released from the air duct, you should have them inspected and likely cleaned. All of the listed reasons are items that require immediate attention. All of these situations could lead to adverse health effects which would greatly impact the respiratory tract of the people who are spending a significant amount of time in the room or building of the ductwork. Some research also suggests that having your air ducts routinely cleaned will improve the overall efficiency, as well as prolong the life of the system itself. It is estimated that nearly 40 pounds of dust is made within a home each year. This dust will then be circulated within the air on a daily basis, and can potentially build up to excessive amounts over time. Some research also suggests that air duct cleaning can save on energy and maintenance costs as well. If you aren’t sure if you need to have your air ducts cleaned, you can get a free quote from a certified professional. The free quote normally doesn’t take very long and will allow you to know how efficiently your air duct is working, and if it will need any maintenance in the near future.
How often should you have your air ducts cleaned?
Depending on the type of room and building, air ducts will need to be cleaned more or less often. A place like a classroom, where fewer air exchanges per hour are needed, will likely require less cleaning than somewhere like a commercialized kitchen would. A commercialized kitchen requires many more air exchanges per hour, so it is quite likely that the air ducts will need more frequent cleaning and maintenance. Additionally, within a home you should consider having your air ducts cleaned more frequently if you have pets. If your pets shed frequently, this can impact the efficiency of the air ducts and over time could impact the air quality within your home. You should also have air ducts cleaned more routinely if someone within your home smokes, or if there is someone that suffers from asthma or allergies. Cleaning of air ducts will help to remove pollen that builds up over time within the system. Experts have said while there isn’t direct scientific evidence to prove that air cleaning immediately improves air quality, but they agree that there are benefits to having air ducts cleaned. Homeowners who have had their air ducts cleaned by a certified cleaner have been pleased with the results. While there is not a requirement for how often your air ducts should be cleaned, there are guidelines. According to the National Air Duct Cleaners Association (NADCA), it is recommended that you get your air ducts cleaned every 3-5 years generally. It is also recommended that you replace your air condition filters around every 3 months or so. This will help to promote cleanliness in your air ducts and will cause them to be more efficient over the long term. The National Air Duct Cleaners Association also says that depending on what part of the country you live in, it may impact how often your system needs to be cleaned. You may use your personal air ducts more frequently based on climate.
How to find the best air duct cleaning companies:
When beginning to look for the best air duct cleaning company, you will want to look for a company that is not only affordable, but that also has a great reputation. Depending on the city that you live in, there are likely one or multiple local, certified, air duct cleaning companies. Some of these companies will offer a free quote to assess if your air ducts actually need to be cleaned, and if they will need any additional maintenance or not. All air duct cleaners should be licensed and in good standing with the NADCA. The company should have been in the air duct cleaning industry for a few years and have a positive overall track record. When talking with the contractor or company, they should be able to show their certification and or license to you. While talking with the company, ensure that they are able to clean all parts of your air duct, and any related components within your personal system. Additionally, asking neighbors or friends can assist in the search for a high-quality air duct cleaner. You should be able to get a free quote or see their price ranges on their website. Generally, the cost should be between $450-$1000. This price can vary depending on the size of the unit and if any additional service is needed, but it is a good starting point. If a company is offering something such as a “99 whole house special”, they are likely doing a very poor job of actually getting your air ducts clean. These types of offers are often made by less reputable companies and should be approached with caution. Many cleaning companies can also be found on Google.com. There may be online reviews that you can read about them. This will allow you to compare cleaning companies if there are a significant amount of options in your local neighborhood.
Why is air duct cleaning important?
As already listed, the cleaning of air ducts can be quite important for many different reasons. They are most important for situations that fall under the following categories:
- A home that contains people who smoke
- A home that has pets that shed
- A home that has recently obtained water damage
- A home that contains people who have allergies or asthma
- A building or home that has been recently remodeled or renovated
Air duct cleaning is also important in preventing and removing biological growth such as mold, fungi, and bacteria. Depending on the material that your air duct is made from, it may be more susceptible to accumulating mold. If left untreated, the mold, fungi, and bacteria can continue to grow and can become aerosolized within your air duct. The mold, fungi, and bacteria will then be continually circulated throughout your building. If you have biological growth within your system, antimicrobial chemicals can be used by cleaning companies to remove the mold and clean the contaminated surface. Any chemical that is used should be approved of and registered with the Environmental Protection Agency (EPA). Most companies that clean air ducts don’t include chemical treatment in their regular cleaning routine, and it may be an additional charge. The EPA has also conducted research that suggests that the cleaning of an air duct system may lead to the reduction of home energy bills. When the unit is cleaned, it may run more efficiently, which will reduce the amount of electricity that it uses throughout the year. The build-up of dust actually leads to airflow being blocked. This will cause the number of air exchanges within a room or building to gradually decrease over time, leading to potentially poor air quality. Clean systems are also less likely to malfunction and will be able to go longer without having maintenance performed on them.
The Benefits of Air Duct Cleaning:
Clean air ducts have many different benefits, some of which have already been listed. The following benefits are among the top 5 benefits of air duct cleaning:
- Promotes a cleaner environment
- Reduces pollen content and allergens
- Helps those within the building to breathe easier
- Can remove odors and smells
- Improves the overall efficiency of the air duct
Air duct cleaning promotes a cleaner environment by removing dust and other buildups that may be circulating in the system over time. Cleaning air ducts also reduces the amount of pollen and allergens in a similar manner. From spring and fall, many different types of allergens and pollen can enter a home or building. Over time these can build up within a system and will continue to circulate in the system until it has been cleaned. Those who have severe allergies many times will notice a reduction in systems immediately after an air duct cleaning. Clean air ducts also reduce the amount of odor and smell within a home at times. Pets, smoking, mold, old food, and other items can all attribute to foul odors over time. Small particles from each of those items can build up within a home, and especially within an air duct. If the system isn’t cleaned, the odor may continue to circulate throughout the home. Over time the odor will sink into the carpet, walls, chairs and the whole home itself. While air fresheners can be used to cover up the smell initially, the smell won’t go away if it is coming from the air duct. Last, cleaning the ducts is affordable and can lead to a better functioning system, which can lead to savings within your electricity bill. Your system will not have to work as hard if it is clean and doesn’t have large amounts of dust built up within it. Overall, air duct cleaning is affordable and can be done by a local, licensed contractor or company.
Sources:
https://www.zerorezatlanta.com/blog/the-top-five-benefits-of-air-duct-cleaning
https://www.arsofmaryland.com/resources/the-importance-of-air-duct-cleaning.aspx
https://nadca.com/homeowners/frequently-asked-questions
https://www.engineeringtoolbox.com/air-change-rate-room-d_867.html
https://nadca.com/homeowners/why-clean-air-ducts#
https://en.wikipedia.org/wiki/Duct_(flow)
https://hughesenv.com/history-air-ducts/
https://www.energy.gov/articles/history-air-conditioning
https://www.epa.gov/indoor-air-quality-iaq/should-you-have-air-ducts-your-home-cleaned
http://www.homeselfe.com/the-types-of-ducts-in-a-home/
http://ductworks.com/air-conditioning/types-of-air-ducts/
https://www.aaaheatingandcoolinginc.com/the-history-behind-home-heating-systems/
https://www.angieslist.com/articles/how-often-should-you-clean-your-air-ducts.htm
