Air barrier systems – also referred to as building wraps – are essential for any modern structure. Their primary goal is to prevent the unwanted exchange of air and moisture.
Most air barrier products are made from polyethylene or polyolefin fibers. Tyvek is the best-known example. No matter the material, all air barrier systems have one thing in common: They’re vital for energy efficiency. Here’s a look at why air barriers are so important and how they impact building regulation and longevity.
1. Prevent Energy Gain or Loss
Houses and buildings tend to gain energy in the summer and lose it in the winter because they exchange air with the outside. According to the U.S. Department of Energy, air leaks are responsible for around 30% of a building’s HVAC costs. Letting these go unchecked represents poor fiscal and ecological judgment.
Ultimately, spending money on climate control is useless without an air barrier system. It helps the home or building keep cool air in during the warm months and shrug it off during the colder ones.
Maintaining a more consistent interior climate and ensuring HVAC equipment only turns on when it’s needed goes a long way toward achieving energy savings at home or in the workplace.
2. Control Moisture Intrusion
A related benefit to eliminating unwanted air exchange is reducing the amount of moisture entering a building. During thermal convection, warm outdoor air gets pulled into a building toward the cooler air within. Nature seeks homeostasis, whether indoors or outdoors.
Wrap systems keep the building’s walls from admitting the moisture accompanying this moving air. Instead of permeating the structure, humidity in inward-moving air condenses and evaporates outside the envelope.
In this way, air barriers control indoor humidity and further reduce the dwelling’s energy expenditure. A well-sealed building envelope using a high-quality air barrier may render whole-house or portable dehumidifiers an unnecessary expense.
3. Protect Building and Occupant Health
Air purification is another costly and energy-intensive expense homeowners and building managers may wish to reduce or eliminate. The right air barrier product can alleviate some of the causes of compromised indoor air quality.
Air barriers prevent incoming moisture from getting trapped within the wall system of the building by providing the right amount of moisture resistance and vapor permeability.
Leaks on roofs can be comparatively easier to locate. However, moisture intrusion within walls can be much more difficult to track down and may do considerable damage in the meantime. Water that collects here can lead to the spread of mold, pollutants from building materials and allergens – all of which have strong ties to unwellness in building occupants.
Allowing moisture to remain here also compromises the durability of a building’s materials. Ensuring each component has structural integrity and lasts as long as possible further protects the building’s envelope. It also prevents the unnecessary waste of energy to run heating and cooling systems – not to mention fabricating replacement materials.
Tips on Air Barrier Installation
There are some challenges associated with installing air barriers successfully during a construction project.
First, air barriers are susceptible to being blown away or torn if installed long before the rest of a wall system, like cladding or siding. Timing the installation of the barrier with the weather and the addition of outer wall materials is critical if builders don’t want to risk damage and rework.
Proper installation of the barrier is required as well. No home wrap system is seamless, which means builders need to seal each join in the material using the proper tape or fasteners. Each air barrier manufacturer will include or offer products they recommend for the best results.
Not using the proper closure techniques, or not bothering at all, will render the air barrier unable to complete its primary objective. It will leave the building drafty, energy-inefficient and prone to moisture accumulation.
Tips on Choosing the Right Air Barrier
Construction professionals who appreciate the advantages of a properly installed air barrier will likely want to know how to choose the right product.
Making the proper choice begins with understanding relevant industrial standards and how they apply to air barriers. The IECC – International Energy Conservation Code® – provides minimum energy-efficiency standards and building codes for renovations and new projects. This and other groups offer guidance that can help steer material and design decisions.
Knowing the stakes can bring sound decisions as well. In the U.S., buildings represent 76% of the nation’s electricity demand and 40% of its overall energy usage. Installing air barrier systems – and engaging in other design techniques that leverage the natural features of a build location, like passive solar – will help bring these numbers down considerably.
The Air Barrier Advantage for Energy Efficiency
Air barriers play a vital role in increasing a building’s energy efficiency. They also prevent damage from moisture that can affect occupants’ health. Professionals should be well-versed in their use and understand how to install them properly to reap all the benefits.