10 Issues Why HVAC Equipment Does Not Perform as AdvertisedBilly Pell
Back in 2012, the National Environmental Balancing Bureau (NEBB) published top ten reasons building HVAC systems do not perform as intended. Here’s a reprint of the ten issues according to NEBB:
- Issue #1: Ductwork is not reinforced for the proper SMACNA pressure classifications.
- Issue #2: Failure to adequately seal ducts.
- Issue #3: Failure to understand the need to seal return and exhaust ducts.
- Issue #4: Failure to adequately pressure test ductwork to prove that duct sealing is effective.
- Issue #5: Failure to understand SMACNA Duct Construction Standards in the fabrication and installation process.
- Issue #6: Failure to properly install turning vanes.
- Issue #7: Duct velocities approaching 2500 fpm may create noise and will cause increased pressure drops in fittings and ductwork.
- Issue #8: The detrimental impact on fan capacity caused by fan system effect is a problem not fully understood by the design industry.
- Issue #9: Drawings with missing dimensional sizes are usually interpreted improperly.
- Issue #10: Most specifications and details call for four duct diameters of straight duct before the inlet to a VAV box, but the actual duct drawings do not have sufficient room to allow for this installation.
(The NEBB article is pages 4-8 in the above PDF link)
The Impact of Ductwork on HVAC Equipment Performance: 2012-2018
A common theme in the 2012 NEBB article was the impact of ductwork on HVAC equipment performance. Fast forward to 2018, proper ductwork fabrication, installation, and maintenance has been proven to be extremely important to getting HVAC equipment performance as advertised in both residential and commercial applications.
Since 2012, many codes for ductwork tightness and testing, including SMACNA, have become more stringent in 2018. The code authorities also suggest the codes will get more strict in years to come to further ensure ductwork supports HVAC equipment performance as advertised/intended.
The air duct system in a building (or home) is used to transport conditioned air from HVAC equipment to desired spaces/rooms. If proper care for the ductwork is not considered, then there may be problems with heating, ventilation, and air conditioning (HVAC) such as hot/cold spots, excessive dust, and high utility/energy bills.
What is Proper Duct Performance in Buildings?
There are three tactics to ensure the air duct system in a building or home delivers conditioned air to the desired spaces/rooms in a building or home:
When installing ductwork (one word), it’s important to wrap the ducts with insulation to avoid the conditioned air losing its conditioned temperature due to the external side of ducts being a different temperature than the inside of ducts.
As you run your HVAC equipment and conditioned air gets distributed through your ductwork (one word), it’s important to clean your ducts to avoid buildup of nasty stuff like dust, dirt, and airborne allergens that can get blown into your living spaces.
To ensure proper duct performance, it’s important to plug any holes/cracks (big and small) in ducts where conditioned air can leak from the ducts before it reaches the desired room/space in a home or building.
How Aeroseal Duct Sealing Improves Buildings
Aeroseal duct sealing is used in commercial buildings around the world to increase energy efficiency and improve comfort and indoor air quality. The following video takes you inside a typical commercial duct sealing project, highlighting the steps involved in using this safe and easy-to-administer process.
Are you a building owner or facility engineer/manager? Find a commercial Aeroseal service provider near you to learn more about the benefits of duct sealing for your facilities and HVAC equipment.
Are you a commercial contractor? We’d love to chat with you how Aeroseal can help you help your customers meet their indoor air quality (IAQ), energy efficiency, and comfort goals for their facilities (municipalities, universities, schools, hospitals, commercial, federal, and more). Call us, email us, or leave a comment below.