NCI Article Library

High-Performance HVAC Resources

Current Article Library Category: Air Conditioning

Estimating Heating Equipment Size and Airflow

An essential part of diagnostic testing is communicating your findings to your customers. Your success will be in direct proportion to your ability to help them understand the impact of system performance on their comfort, pocketbook, health and safety. Back when...

Economizer Repair Opportunities Are Everywhere

Economizer Repair Opportunities Are Everywhere by Rob "Doc" Falke Economizers have stepped into the spotlight recently as one of the prime opportunities for energy savings in the commercial HVAC marketplace. It's said, with little argument from those in the field,...

Duct Sizing Made Easy

ACCA manual D and other similar programs are the industry standards for duct sizing. But from hundreds of unofficial polls conducted in our seminars, we have learned that in the "real world" these programs are used for designing less than 1% of the residential and...

Duct Loss Test Methods – Which to Use When?

Duct Loss Test Methods - Which to Use When? By: Rob "Doc" Falke, NCI President NCI has a number of duct loss test methods that can help identify defects in duct systems. But when it's time to test in the field, you have to quickly determine what test will be most...

Duct Access Solutions

Many performance-based contractors have learned a few tricks that help enable effective duct system renovations when access to the existing duct system is limited or challenging. Let’s take a look at a few of these solutions to improve duct performance when ducts are...

Diagnostic Tests That Teach and Sell

Since the mid 1980's most contractors have been selling air conditioning and heating using methods like slick calculations that promised return on investment and energy savings. Times have changed and so have our customers. Today's buyers are better equipped to make...

Diagnosing Cooling Systems

Compared to the majority of the service techs in our industry, airheads have a distinct advantage when it comes to diagnosing cooling systems. The general idea that the system is "working" means it's typically only producing 60% or less of the equipment rated BTU...

Design Vs. Redesign

We've looked, but can't find it. There are mountains of information about how to design a new HVAC system, but nothing much that addresses how to redesign one. It would take hundreds of pages to completely detail the process, but let’s take a stab at the basic ideas....

CSER Enters Its Second Year

CSER Enters Its Second Year by Rob "Doc" Falke Since the introduction of CSER™ (NCI's Cooling System Efficiency Rating), last year, the number of contractors that measure their system's total BTU delivery has skyrocketed. Many have enjoyed the benefits of measuring...

Changing Fan Speed with an Adjustable Pulley

Changing Fan Speed with an Adjustable Pulley by Rob "Doc" Falke Adjustable pulleys are the most commonly used method for changing fan speed in commercial balancing. Let’s take a look at how adjustable pulleys work and learn how to adjust them. We’ll also learn how to...