NCI Article Library

High-Performance HVAC Resources

Is Airflow Measurement Enough?

Is Airflow Measurement Enough? Rob "Doc" Falke, NCI President Recently a long time successful NCI contractor contacted me concerning a light commercial project he was struggling with - a 7 ½ ton and a 5 ton unit servicing an office area with sixty uncomfortable women....

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...

Insight Air, Phoenix, AZ

Rick Rohrbacher is the owner of Insight Air located in Phoenix Arizona. In addition to having his second daughter two weeks ago and moving into their new home two weeks from now, it's been a very busy spring at for Rick and the rest of his company. As we spoke with...

Induced Draft & Atmospheric Common Venting Interference

When an Induced Draft Appliance (Furnace, Boiler, Water Heater) is "Common Vented" with an Atmospheric Appliance, venting interference can occur. This procedure is the proper method to evaluate this situation and take all precautions to verify safety. Necessary tools...

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 Interpret Fan Performance Data

One test essential to successful CoolMaxx™ service reporting is interpreting fan airflow from the manufacturer's fan data after you measure total external static pressure. As with most HVAC system diagnostic testing, it takes more than textbook learning to become an...

How to Implement CoolMaxx for Maxximum Success

Since the heat has settled over most of the country we have had an increasing number of calls reporting a wide range of methods of implementing the CoolMaxx report. While many of the variations are interesting, after a discussion of how we intended CoolMaxx to be...

How to Generate Leads With HeatMaxx™

Ok, so you've trained your techs on how to test initial system performance with HeatMaxx™. You've got the forms and the right tools. So how do you generate leads form your service calls, and just as important, how do you follow up a lead from a low-scoring HeatMaxx™...

Heat Strip BTU and Performance

Since the cold has set in we have received many calls and e-mails on PerformanceTalk from contractors and technicians wresting with electric heat systems. The two main topics discussed are: How to determine and rate electric heater performance and how to figure the...

Fresh Air Requirements

Since the ASHRAE IAQ Standard 62 has been in turmoil for over a decade, we've put together a few rules of thumb to consider when designing and testing fresh air in homes and buildings. Fresh air intake = Occupants in a building X 15 CFM To maintain an adequate...