NCI Article Library

High-Performance HVAC Resources

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....

Coziahr Heating & A/C – Council Bluffs, Iowa

Dave Coziahr operates a small HVAC contracting and energy services company in Council Bluffs, Iowa. We selected Dave as August's NCI Contractor of the Month primarily because of his passion for testing HVAC systems. In college Dave was introduced to the SMACNA Systems...

Combustion Air Diagnostics

According to NCI's Protocol, rising CO readings indicate combustion air or venting problems. In either case, flue gases are spilling into the space, requiring immediate attention. By measuring draft you can differentiate between venting and combustion air problems....

CO Tip – Plugging PVC Flue Test Holes

David Richardson, of Frankfort Kentucky, Tech Tip

CO & Combustion Repair Procedures

Many NCI members have requested that we include repair procedures in our member downloads. October's theme is CO and Combustion testing, so we have included some one-page repair procedures that you'll find helpful this fall while addressing heating system performance....

Brian Garno, Garno Brothers, Swartz Creek, MI

Brian Garno, of Garno Brothers serving Genesee County on the Lower Michigan Peninsula has been selected as this months NCI contractor of the month. Brian also owns and operated Balance Pro, a professional air balancing company serving South Eastern Michigan. You may...

Balancing a System with Zoning

Balancing a zoned system requires a few more steps than balancing a typical constant volume system. Let's take a look at a zoned system balancing procedure and investigate the differences. The first step is to inspect the system and compare the plan to what actually...

Balance More Than Just the Air

Remember your first day in NCI's air balancing seminar? Most of us registered for the class thinking we were going to learn how to use a balancing hood and adjust dampers and that would be about it. By the end of the seminar your head was swimming with all the...

Are You Sizing Ducts and Fans Correctly?

When it comes to sizing HVAC ducts, we all have some interesting stories to share. One saying that many of us often repeat is "every duct system we ever designed worked perfectly, until the day we got our first air balancing hood." We all learned a few things that...

Air Diagnostics Tip – Understanding Register AK Factors

Nearly all grille manufacturers publish a ‘free area' for each grille or register. The question is, are these free area factors meant to be used as a correction or Ak factor? Are these numbers meant to correct for the change in air velocity as it passes through a...