NCI Article Library

High-Performance HVAC Resources

Interior Doors and Intermittent HVAC Comfort Problems

Interior Doors and Intermittent HVAC Comfort Problems by David Richardson This cooling season, HVAC professionals across the country will be called upon to solve intermittent comfort problems they can't recreate. These frustrating and random problems often involve...

Increase Temperature Measurement Accuracy

When measuring system or equipment temperatures, take your measurements as soon as the system stabilizes. This will allow your performance calculations to resemble (as close as possible), normal operating conditions. In order to keep the system running during testing,...

Include the Ducts in Your Service Agreements

Adding the ducts to your service agreements is one of the best steps you can take to move your company forward in implementing air diagnostics. It's a small thing that can bring great and immediate results. Spring is the perfect time to implement this new service....

If You Don’t Measure, You’re Just Guessing

If You Don't Measure, You're Just Guessing by David Holt, NCI Director Sales & Service Leadership I’m a huge college football fan. When the games begin in late August, I’m either glued to the TV or I’m visiting football stadiums around the country enjoying some...

Hydronic Balancing: A New Frontier for NCI Contractors

As we are in the process of developing a commercial air and water balancing training and certification program for larger systems, we have been creating hydronic balancing forms and procedures. Water systems have been an integral part of commercial air conditioning...

Humidity Testing Tips

The primary challenge in effectively measuring humidity is accuracy. The two major elements affecting accuracy are the reliability of your test instrument and the measurement technique that you use. Choose a good quality instrument. Many low cost instruments are...

HSER™ Season is Upon Us

HSER™ Season is Upon Us by Rob "Doc" Falke In May of 2004 we released the CSER ™ and HSER ™ procedures to NCI Members. With the success many members have enjoyed with CSER this summer, several members requested that we address HSER again this fall with additional...

How to Use Fan Performance Data in Your Diagnostics

Almost every day we receive requests for additional generic fan performance tables other than .50" table we published previously. Well, you asked for it, you got it. We've just introduced two new generic tables, one for constant speed blowers with up to .80" ESP and...

How to Use Air Density Correction Factors

Air density correction factors have been a part of our air balancing curriculum since the early 1990's. NCI published a small table years ago and encouraged you to make corrections for air density when measuring airflow at higher altitudes. But the accuracy you are...

How to Size a New Fan Belt

When you spin an adjustable pulley and increase its diameter to squeeze a little more air out of a belt-drive fan, there are times you'll find the old belt no longer fits. The first fix is to loosen the bolts on the motor mount and slide the motor as close to the fan...