Finding Fall IAQ Opportunities
When temperatures are mild, indoor air quality (IAQ) begins to suffer. When heating or cooling demand ceases, necessary functions such as ventilation, dehumidification, and filtration terminate as well. However, some opportunities exist...
Air Temperature Measurement Basics
A claim was made in a regulatory meeting I attended in August in California that shocked me. A prominent building scientist claimed that supply air temperature could not be effectively measured at the equipment. Since that time I have met with hundreds of HVAC contractors and technicians that accurately measure equipment and system temperatures and effectively measure the live operating performance of HVAC systems. Let’s look at some basic temperature testing principles so we can know for sure the performance of the HVAC systems we work on every day and overcome the old idea that live system performance cannot be measured...
Measure for Adequate Duct Size in Two Minutes
There’s lots of discussion being kicked around these days about residential ducts being substantially undersized. Here’s a two minute test that can check the size and performance of your duct system. The instruments are inexpensive and it takes less than 10 minutes to learn how to do it....
Recalculating Filter Pressure Drop
When reading filter manufacturer’s engineering data, the pressure drop is often listed at a CFM lower than what you would intend to use. Let’s take a look at how you can find what the filter pressure drop will be at the higher airflow....
Half Inch Fans Have Gotta Go
The era of the typical residential fan being rated at .50-in. is coming to a close. With the increasing pressure drops over today’s cooling coils and filters, it’s not uncommon to find filter and coil pressures exceeding rated fan pressures…that’s excluding the pressure drop of the duct system! The result is fans that are delivering dangerously low airflow, which results in poor system performance and shortened equipment life. ...
Duct Sealing Issues
As we hear more and more about duct sealing programs, and the promise of energy savings to our customers, we must be aware that there’s no guarantee of reducing utility costs in every case when you seal ducts. As a matter of fact, there’s a 50/50 chance power consumption may increase....
The Best of Rob 'Doc' Falke
Sometimes the best way to learn something is to dive in and get your hands dirty. Rob 'Doc' Falke has been sharing his industry knowledge and expertise through his technical articles in the Hotmail newsletter for several years...
Kitchen Exhaust Opportunities
Kitchen hoods are one of the greatest opportunities in air diagnostics and balancing. Each system moves 5 to 10 times more air than a heating or cooling system serving an equal area. Balancing these systems provides a valuable service that delivers increased comfort and provides significant energy savings for our customers....
Cold And Clammy Cooling Systems
There’s a kind of air conditioning that’s remarkably uncomfortable. The air feels heavy and cold, but it’s also clammy. The thermometer is at a temperature that should be comfortable, but you want to turn it down lower. What’s going on with the system?...
How Does Air Balancing Save Energy?
Air balancing is a small profession with less than 3,000 commercial supervisors certified by four major organizations. There are fewer than 7,000 residential balancing professionals certified by National Comfort Institute. So, there are less than 10,000 certified air balancers in the world today. (For comparison purposes, there are over 800,000 brain surgeons in the world.) ...
Use Manufacturer’s Equipment Information
While equipment manufacturer’s installation instructions contain essential “how to” information, engineering data contains “how much” information. Let’s take a look at what essential information is contained in this paperwork and how it can make life easier if we take time to use these installation and testing tools....
Buyers Beware
An increasing number of building performance contractors are entering the HVAC industry at an alarming rate. This new breed of contractor has the potential to deliver effective all inclusive energy packages, but some newcomers are installing the worst quality HVAC systems we’ve seen in decades....
Oversized and Underperforming Equipment
Energy Stewards International, an NCI Company in Des Moines, completed an interesting study in Iowa providing new evidence that although most equipment is significantly oversized it performs so badly, that it is actually about the right size. If this is true, new opportunity is available for contractors that can actually size equipment correctly and get systems to perform as they should. ...
Airside Vs. Refrigerant Performance Measurement
When it comes to performance measurement and air conditioning systems, most master technicians gravitate to one of two measurement techniques, the airside or the refrigerant side. ...
Are Variable Speed Fans Becoming a Necessity?
The more HVAC performance test reports I review, the more I’m convinced that variable speed motors are becoming a necessity. As coil and filters are being built to more “efficient” specifications, their resistance to airflow has increased to the point where a typical constant speed fan can rarely deliver the required airflow to allow the system to operate properly....
How to Measure Residential Hydronic System Btu
Since winter has arrived, let's take a look at how to measure the Btu delivery of a residential hot water heating system. This will be a brief introduction to water system Btu measurement. ...
Test, Teach and Sell with These Four Air Diagnostics Tests
Once upon a time, our ability to sell HVAC equipment was based on a marketing piece from a manufacturer, or claims we made of our exquisite service. ...
A Short Investigation
Before you replace HVAC equipment, it’s a good idea to assess the condition and performance of the existing system and evaluate its capacity to accept the new equipment and new accessories. The odds of new equipment working on an old duct system are not great. ...
Practice What You Preach
How can you recommend something to your customers that you don’t use? That’s a valid question that each of us should answer. Surely, if you use the same products at home that you sell at work, you’ll be able to speak with conviction and offer valuable advice to your customers with confidence and first hand experience. ...
Look Before You Leap
Before replacing HVAC equipment, how many of us take time to assess the performance of the existing duct system? Although the number is small, the idea...
RESIDENTIAL OVAL DUCT AIRFLOW PERFORMANCE
A contractor called our office with a question about oval duct airflow performance. Its a typical concern that we hear from time to time, usually because...
Can Heat Pumps Handle More Filter Pressure Drop?
As filters continue to increase in efficiency, one parallel fact is that usually the pressure drop over the filter also increases. According to Fan Law...
ADD DUCT RENOVATIONS TO EQUIPMENT REPLACEMENTS
Over the last decade the term duct renovation has been heard a lot in the HVAC industry. The term refers to the process of testing, diagnosing, repairing, and balancing duct systems....
Measuring Fresh Air With a Thermometer
We had quite a number of calls about my previous article regarding the correct amounts of fresh air to bring into HVAC systems. One recurring question was: “Is there a way to measure fresh air if I don’t have a full set of air balancing instruments?”...
Measuring Static Pressure
Manometers or pressure gauges have been used to measure air pressures for more than 200 years. The fathers of our industry used these gauges to learn about the mysteries of fans and duct systems....
