Duct & Ventilation Services
Have you ever walked into a home or office and immediately noticed that the air smelled stale, off-color or just wrong? The problem could lie in the duct work and ventilation of the space, as inadequate ventilation and dirty or moldy ducts can cause a variety of health and environmental issues. Whether the ventilation challenges are caused from excess condensation or a lack of ventilation, the outcome is the same: a build-up of pollutants and chemicals that can be difficult to detect. This is particularly difficult for individuals with respiratory illnesses such as chronic bronchitis or asthma, but will affect nearly everyone to some extent. As our homes and office buildings become even more airtight, this is a problem that will continue to surface. Adequate ventilation goes beyond opening windows to air out a home, and must be intentionally crafted as part of the building’s infrastructure.
Modes of Ventilation
Ventilation is the process of moving air between rooms within a building, or moving outdoor air into a building or a particular room. Proper ventilation is important because it can remove or dilute pollutants from the breathing air in a building. The three main mechanisms of moving air within or through a building are natural, mechanical and hybrid — or mixed-mode — ventilation.
- Natural ventilation occurs when natural forces such as wind or thermal buoyancy force air in, out or through a building structure. Solar chimneys, wind towers, doors, windows and trickle ventilators are all examples of how air moves naturally through a building.
- Mechanical ventilation is just that: air driven by some mechanism through a structure. Mechanical ventilation is often built into the infrastructure of a building and can include everything from fans to ductwork. Mechanical ventilation is helpful in removing condensation from buildings and from reducing the amount of mold, mildew and other pollutants from the air. These systems can be based either on positive or negative pressure, with positive pressure being a pressurized system that pushes air from a room and negative pressure systems pulling air from a room.
- Hybrid ventilation, or mixed-mode ventilation, relies on a combination of natural and mechanical ventilation to drive pollutants and condensation from the building. When natural forms of ventilation are inadequate, these systems are designed to move to a more mechanical and active state. The hybrid option offers energy savings but does have a trade-off in terms of potential additional installation cost and the sound of the fans utilized in this type of ventilation system.
Types of Ductwork
There are two main types of ductwork that move heated and cooled air through your home: flexible and rigid.
- Flexible ductwork is more pliable, and is generally made up of a bendable plastic that is surrounded by insulation to make it quite durable. When it’s not possible to install the more rigid ductwork in tricky spaces or when you have need for a kick or a bend in the ducts. While this material is more usable in a tight spot, it is not quite as durable as rigid ductwork. Flexible ducts must be properly installed and secured in place, or they are subject to degradation of their structure such as sagging or snaking — all of which can reduce the efficiency of air flow throughout the building.
- Rigid ductwork comes in a variety of sizes and materials and tends to be more efficient, effective and durable than flexible ducts. There are three key types of rigid ductwork:
- Sheet Metal: Generally made of aluminum or galvanized steel, sheet metal ducts are likely what comes to mind when you think about ductwork. They are relatively light and easy to install and have few hiding spots or kinks that could encourage the growth of mold or mildew.
- Fiberglass-lined: In some applications, sheet metal ductwork is lined with fiberglass to muffle the sound of the air conditioning. While effective, the fiberglass insulation does tend to deteriorate over time and could potentially release fiberglass insulation particles into the building’s atmosphere. Cleaning is also more difficult for this type of ductwork which can lead to the buildup of bacteria and mold.
- Fiberboard: Fiberboard balances some of the benefits of fiberglass lined ducts with the benefits of bare sheet metal ductwork. Fiberboard is created by compressing and bonding fiberglass strands with a resin, which is then covered by sheets of foil. The layer of insulation added by this process is beneficial, but the efficiency of the ductwork is not as great as bare sheet metal. This type of rigid duct can also become a breeding ground for colonies of mold, especially in climates with a higher humidity.
When to Clean Your Duct System
While the U.S. Environmental Protection Agency has not issued definitive guidelines on when to clean your ductwork, there are certain understood standards that will help you determine if this is a necessary action. It is possible that your ventilation system harbors significant colonies of mold or dirt, but it is thought that much of this contamination stays within the duct system itself and doesn’t travel into the home or office environment. However, cleaning ducts is recommended in instances where there is visible mold growth, whenever you have a rodent or insect infestation, or excessive amounts of dust and debris are being released into your building and clogging the air supply registers. There is no set schedule for cleaning or replacing air ducts, but most types of ducts can be easily cleaned by professionals familiar with the task. If your air ducts become too contaminated for cleaning, then replacement of a portion or all of your duct system may be recommended.
Life Expectancy of Duct and Ventilation Systems
Just as with many systems in your home, the life expectancy is determined by how well it is maintained and the initial quality of the system. Everything from changing your air filters to removing external debris and getting seasonal checkups can extend the life of your ductwork as these all contribute to the amount of contaminants moving through the system. While flexible ducting may seem like a better option for the ability to move through various spaces, it’s important to know that the life expectancy of this type of system is much lower than for a rigid sheet metal ventilation system.
Understanding how ductwork and ventilation works and how it affects the breathable air in your home or office allows you to make good decisions when faced with building or remodeling decisions. While rigid metal ducts allow for a longer lifespan and a better overall flow of air, there are times and spaces that will only allow for a more flexible system of ducting. When you have the right type of ventilation system for your space and have it properly maintained, you’re ensuring a safe and healthy living environment for your home or office.