Article Categories:
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? 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...
by Jim Davis
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...
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...
by National Comfort Institute, Inc.
Most of us who seal metal ducts using mastic know how hard it is to neatly brush the mastic on joints. This is no big deal on ducts in attics or crawl spaces, where they'll never be seen, but can look kind of sloppy on exposed ducts in basements and equipment rooms....
by Jim Davis
Many of us have been taught that if draft in the flue is .02" W.C. or higher, everything is working fine. This is a very dangerous assumption because you don't have enough information to make an educated diagnosis. Remember, none of the above methods can differentiate...
by Jim Davis
While some of us are already dealing with summer air conditioning work, in many parts of the country some of us are still dealing with heating. There's also a large number of contractors that aren't doing heating or cooling work because it is between seasons. This...
by Jim Davis
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...
by David Holt
Don't Be Victor Frankenstein In 1818, Mary Shelley published Frankenstein, her best-selling horror classic about an experiment that goes horribly wrong. Swiss student, Victor Frankenstein, uncovers the secret to bringing life to that which is lifeless. In assembling...
by Jim Davis
What's my liability when I make the job right? This is a commonly asked question once contractors are taught how to diagnose and fix combustion safety and efficiency problems. My first response is another question: "Does ignoring or not diagnosing problems reduce your...
