NCI Article Library

High-Performance HVAC Resources

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...

Four Seasons Air Conditioning and Heating Company, Kingsville, TX

Jim Altman, President of Four Seasons Air Conditioning and Heating in Kingsville, Texas, September’s NCI Contractor of the Month.

Flow Hood Calibration Quick Check

From time to time you may question whether your flow hood is reading accurately. Most of the time, when you're using a quality hood like the TSI 8371, you'll find that even though you might be getting a questionable reading, the problem is not the hood, but the outlet...

Estimating Heating Equipment Size and Room CFM

Many members called our tech support line this last month as you've shifted gears to test in heating mode. A large number of the conversations have been about sizing heating equipment and how to estimate room heating airflow. So let's get back to the basics and review...

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...

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 Leakage in Mechanical Rooms and CO

Mechanical rooms housing heating equipment are required to maintain a neutral or slightly positive pressure to prevent combustion gasses from being pulled back down the flue into the room. The only appliances that this would not affect would be sealed combustion or...

Don’t Let “Mother Nature” Control Your Summer Success and Profits!

We all love hot, humid and miserable weather in the summer because it's good for business. Unfortunately in many parts of the country that's not been the case the past few years, and for many, business just hasn't been what it should be. But should air conditioning be...

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....