< Previous10 NOVEMBER 2020HIGH-PERFORMANCE HVAC TODAY how important that is. Session 2: Coach Your Managers: Con- tractor David DeRose of Masterworks Mechani- cal, Craig, CO presented attendees how, after the team knows the performance mission, to coach other managers on some of the subtle changes necessary to integrate higher performance into the company. Session 3: Coach Your Technical Team: NCI Instructor Casey Contreras presented the field perspective on integrating performance testing into service and installation technicians’ daily work. He shared the importance of how to support the technicians during the transition to High Performance and also coach them on the processes necessary for success. Performance Town 2020: Hands-on Demonstrations: NCI’s Performance Town re- turned to Summit this year. Three workshops lead by NCI’s Rob Falke, Jeff Sturgeon, David Rich- ardson, Casey Contreras, Scott Fielder, and Justin Bright provided contractors with insights on how to conduct testing and calculations in the field. The Performance Town workshops also de- tailed how to diagnose issues and offer customers choices on profitable system upgrades. All attendees to these workshops received NCI’s new detailed procedures and quick reports to use with attendee’s management teams coaching. Session 4: Coach Your Sales Team: The final step is integrating a High-Performance sales A nother Summit event is in the books, only this one was so very different from all the rest. Because of the COVID-19 Pandemic, Summit could not be held as an in-person event and so, was converted into a live online event in very short order. It is safe to say that despite having to do this virtually, Summit 2020 actually attracted more HVAC contractors than any previous Summit and, despite some technical glitches, the interac- tion between speakers and attendees was superb. More than 230 HVAC contractors from across the country got together online from October 5-7 to learn how to coach their teams to success. BREAKOUT SESSIONS This year’s theme was “Coach Your Team to High Performance.” From the opening session through every workshop, attendees learned how to coach all their team members. The breakouts were as follows: Session 1: Coach Your Entire Team: NCI’s David Richardson presented how contractors can coach their teams on what High-Performance contracting is and why the company should be on that path. He focused on how attendees can use data from performance testing to not only help contractors differentiate by delivering the best possible products and services, but also to help employees understand The First Virtual NCI Summit Takes the Industry by Storm By Mike Weil MANAGEMENT YOU CAN NOW ACCESS RECORDED SUMMIT SESSIONS AND VIRTUAL TRADE SHOW. JUST GO TO GOTOSUM- MIT.COM TO LEARN MORE.NOVEMBER 2020 11HVACTODAY.COM ● Greg Wallace, Owner, Progressive Heating, Newnan, GA. This highly interactive discussion was one of the highlights of the three- day virtual event. IDEA MEETING The Annual Idea Meeting has been a popular Summit event from very ear- ly in its history. This is where contrac- tors gather to share their ideas on how to creatively build lead generation and sales into their companies. Once the ideas were presented, all the session attendees voted on the best idea in each of the two categories. The 2020 winners were: Lead Generation: Ronald Ama- ya of Punbar LLC in Houston, Texas. His idea was to better serve his multi- cultural customer-base by developing bilingual websites with Spanish and English options. Sales: Will Horner of Canco Cli- mate Care in Ontario, Canada. Will’s winning idea was to provide home- owners with “Birth Certificates” for their new or renovated HVAC sys- tems, then use those to help close sales with other customers. Both ideas earned the winners $310 in cash. And finally, NCI Chairman and CEO Dominick Guarino announced that the 2021 High-Performance Summit will be held in-person in Branson, MO as long as the Pandemic is under con- trol at the time. Stay tuned for more information as we get it. approach with your sales team. NCI’s David Holt led this session and he discussed how to coach both inside and outside salespeople on the specif- ics of adding air upgrades and renova- tions to their proposals. This includes the practice of know- ing when to price the work themselves and when to bring in higher-level technical expertise. NCI PARTNERS TRADE SHOW For the first time, attendees expe- rienced a virtual tradeshow where they visited booths, attended one-on- one and group meetings online, then downloaded brochures, catalogs, and more. Booths were “manned” by the exhibitors who had plenty of “face- time” with attendees. PANEL DISCUSSION In addition to the sessions and work- shops, this jam-packed Summit also included a number of special events including a contractor panel discus- sion moderated by Dominick Guarino. The topic: how the COVID-19 Pan- demic impacted their business and what they did and are currently doing to meet those challenges. Panelists included: ● Dawn Mroczek, Comfort Consul- tant, GV’s Heating, Glenview, IL ● Dave DeRose, Founder, Master- works Mechanical, Craig, CO ● Dan Squires, President, Vincent’s Heating, Port Huron, MI ● Michael Greany, Service Manager, All Pro Plumbing, Ontario, CA NCI’s 16th Annual Contractor Recognition Program In NCI’s Annual Awards Presentation, member companies are recognized for various achievements during the year. CONTRACTOR OF THE YEAR AWARDS This year’s winners include: n Small Contractor of the Year – Under $2 million in sales: Four Seasons Air Conditioning and Heating, Kingsville, TX n Medium Contractor of the Year – $2 to $6 million in sales: Kennihan Plumbing, Heating, and Air Conditioning, Valencia, PA n Large Contractor of the Year – More than $6 million in sales: Jansen’s Heating and Air, Effingham, IL. OTHER ACHIEVEMENTS Furthermore, NCI recognized several individuals for outstanding achievement. Award recognition went to: n John Garofalo Implementation Excellence Award: All Pro Plumbing, Heating, Air, & Electrical, Ontario, CA n David Debien Award: Vic Updike, Masterworks Mechanical, Craig, CO n Scott Johnson Training Excellence Award: Getzschman Heating, Fremont, NE n Sales Excellence Award: Dawn Mroczek, GV’s Heating and Cooling, Glenview, IL n Preferred Partner Award: R.E. Michel, Inc., Glen Burnie, MD n Chairman’s Award: Ronald Amaya of Punbar LLC, Houston, TX.12 NOVEMBER 2020HIGH-PERFORMANCE HVAC TODAY call? We say we are cer- tified in Air Diagnostics and Air Balancing, but we don’t show them any proof! Furthermore, since they don’t follow us around the house, how will they know what we find? All these ques- tions led me to a new way of presenting all the test data we gather into a “Performance Report,” along with a ComfortMaxx™ (ncilink.com/ CMaxx) summary, and proposal. So, what is a “Performance Report?” After re- ferring back to our NCI class materials, we de- cided to start creating some forms including the following: ● Cover page (Air Balance Report Certification) ● Certification Certificates ● Notes and Remarks ● Test and Balance Deficiency Report – with Corresponding Pictures ● Test In – ComfortMaxx ● Proposal. If you would like to see a sample of our playbook, go to ncilink.com/Playbook. COVER PAGE The cover page really is the “Air Balance Report Certification” page that comes with NCI’s Com- mercial Air Balance class. This page includes: ● Date ● Project name ● Which system – 1st Floor / 2nd Floor etc. ● Technician name ● HVAC contractor information W hen clients ask about who is com- ing to their home to provide a free estimate, they seem to always think its “Don.” When I arrive, they are a bit surprised that I’m a woman and my correct name is Dawn. Being in a male-driven industry requires quite a bit of hard work and self-confidence. I first started as a Comfort Specialist in 2006, and GV’s Heating and Cooling was just like all the other HVAC com- panies in our market area; we sold boxes. Then we decided things needed to change. We needed to find the true value as to why cli- ents choose GV’s to do the work. So, in 2010 GV’s joined National Com- fort Institute (NCI), and we started implement- ing static pressure and temperature testing on every sales call. QUESTIONING EVERYTHING In 2018 I attended NCI’s Commercial Air Balancing and Duct Renovation classes. That experience opened my eyes to the fact that we were not closing many duct renovation jobs. So it was time to re-evalu- ate our sales process. I asked the following questions: How do clients know exactly what measurements we took? And why? How are they supposed to remember all the information we present to them during the house Use A “Performance Playbook” To Close More Sales By Dawn Mroczek SALES The “Playbook” always includes the technician’s certifications to build credibility with the customer. This is the “Playbook” cover page which is very much like NCI’s Air Balance Report Certification page.NOVEMBER 2020 13HVACTODAY.COM ❒ Dirty Blower: A dirty blower wheel decreases the system efficiency ❒ Melted Rings: The water heater may not be venting properly – com- bustion analysis must be done for safety concerns. Under each item listed above, we have a corresponding picture number. TAB DEFICIENCY REPORT — CORRESPONDING PICTURES In this portion of our report, we in- clude all the pictures that correspond to the Notes and Remarks page. We are very specific with the pictures we provide. ● High TESP: From taking a pic- ture of the Magnehelic with the TESP, compared to the rated TESP on the furnace nameplate ● Low- or High-Temperature Drop: Take a picture of the psy- chrometer with measured tempera- tures vs Manufacturer’s heat specs on the furnace nameplate ● Restrictive Filter: Take a picture of the filter ● Dirty Filter: Take a picture of the filter ● Blower Speed: Take a picture of wiring or dip switches on circuit board ● Restricted Fitting: Take a picture of fittings ● Undersized Duct: Take a pic- ture of supply trunk(s) and/or return trunk(s) ● Dirty Blower: When the furnace is off, reach into the blower compart- ment and take a picture of the blow- er wheel ● Melted Rings: Take a picture of melted rings around hot and cold water on the water heater. PLAYBOOK The performance report helps create a playbook for our installation crew: ▲ The playbook provides a thorough ● A summary ● NCI certified # / Expiration date. Following the cover page, we include the certificates we earned from NCI. NOTES AND REMARKS This is one of the most important pages in the report. Notes and Re- marks contains a list of all the issues found for each part of the whole-house comfort system: 1. High Static Pressure 2. Low or high-temperature drops 3. Restrictive filter 4. Dirty filter 5. Blower speed set wrong 6. Restrictive fitting 7. Undersized ductwork 8. Dirty blower 9. Melted rings on the water heater. Also included in the Notes and Re- marks area is a checkbox denoting whether the issue remains open or is closed after the visit. And finally, we include a section for Contractor Remarks. Typically, this is where we share the data we collected: ❒ What was the TESP: Measured TESP vs Manufacturer-rated TESP ❒ Temperature Drop: Measured temperature drop vs manufacturer- rated temperature drop ❒ Restrictive Filter: Pressure drop of filter vs Standard filter drop ❒ Dirty Filter: Pressure drop ❒ Blower Speed Set Wrong: 400 CFM (Buckets of air/ton) have 3.0-ton blower speed, but it’s set to 4.0 tons ❒ Restrictive Fitting: Measured pressure of return or supply ❒ Undersized Duct: We get this data from the NCI Clipboard based on actual duct size compared to the amount of CFM needed for that spe- cific system This page from the GV’s Performance Playbook shows the TAB Deficiency Report.14 NOVEMBER 2020HIGH-PERFORMANCE HVAC TODAY nected to its side. It has about 8-in. of wasted space in the front where the air cannot be brought into the blower compartment. I measured the following pressures: ● .74-in. w.c. return pressure ● .66 supply pressure. The supply and return ducts are un- dersized based on the amount of CFM needed for the system to run efficiently. So, we removed one of the ducts from one of the main supply trunks and brought it back to the supply plenum. We also brought back a return to the return drop to bring more air into the furnace. We increased the return air- drop and installed the filter in the hor- izontal position. After completing all the ductwork renovations and balancing the sys- tem, we retested it and found we had reduced the system to .70 TESP. This was exactly to the manufacturer’s specs! We hadn’t even finished the job on day one and the customer stated the next day that he already noticed a huge difference in comfort. REVIEW Professional, Punctuality, Quality, and Responsiveness are just some of significantly hotter than the first floor in the summer. When Mr. Blanchard walked me throughout the house, I experienced it myself. Turning the thermostat to cooling mode, I proceeded with my favorite part of any call — collecting the data. I measured static pressure, tempera- tures, and airflow. I checked out the duct sizes blower speeds. Then I cap- tured the information from the fur- nace and air conditioner nameplates. When Mr. Blanchard reached out to schedule the job, he asked me if zon- ing would work. He mentioned to me that he received another quote and the other company recommended adding zoning. I explained to Mr. Blanchard that he didn’t have ductwork dedicated to the first and second floor, plus with the measured high TESP, zoning would put a lot more pressure on the system. The existing furnace and air con- ditioner installed in this home are about a year old. It is a variable-speed furnace, paired with a single-stage air conditioner. This particular brand of furnace cannot have a media filter cabinet con- outline of the changes we plan to make at a client’s home to improve the sys- tem’s comfort and efficiency ▲ Makes it easier to hand off the job from sales to the installation crew ▲ The playbook is attached to each job in ServiceTitan. COMFORTMAXX™ For any sales call scheduled for a furnace/air conditioner replacement, or a client suffering from hot and cold spots, we provide a ComfortMaxx™ Test-in Report (hvactoday.com/ comfortmaxx). This is a great way to show a client how their existing system is actual- ly performing from a third-party ap- plication. The report provides a great breakdown of where the system has high pressure based on our data: 1. Supply 2. Return 3. Filter Pressure Drop 4. Coil Pressure Drop. The report is a great visual aid with a gauge. It backs up the information you provided in the Performance Report. PROPOSAL In the proposal, we include all the recommendations from the Perfor- mance Report. We find that since we started this process, most of the time the customer goes with the best option, and no longer does things in stages. EXAMPLE: THE BLANCHARD RESIDENCE One of our team’s biggest accom- plishments was improving the com- fort and efficiency of a newly renovat- ed house. The Blanchard’s just bought the home from a builder. They com- plained to us that the second floor was SALES The ComfortMaxx™ Report is a great way to show customers how their systems are actually performing from a third-party application. NOVEMBER 2020 15HVACTODAY.COM home’s needs. Everyone I worked with was knowledgeable and professional. “The way they worked with me made me feel like they truly cared about their work and making sure the air was right and that I had a good experience. Fair warning, they are not cheap, but it has been well worth the money.” WHERE WE ARE HEADED GV’s is never satisfied with where we are. We always strive for new ideas to avoid obstacles that may come our way. The COVID-19 pandemic did not stop us much. We worked harder and are currently financially ahead of last year. This also helped us regain our fo- cus on our core values: Humble, Hon- esty, Integrity, and Hungry. We strive as a team to bring GV’s to the next level and become “The Perfor- mance Contractor” in the Chicagoland area! If it wasn’t for the NCI Perfor- mance Coaches and the monthly Trail- blazer team, we would not be where we are today. the words that Mr. Blanchard used to describe his experience with our company. After we completed the Blanchard job, we received the follow- ing raving review: “I really enjoyed working with this company. From beginning to end, GV’s excelled. We had issues with airflow in our home and the upstairs was signifi- cantly warmer than downstairs. “They provided a free estimate and discussed the recommended ductwork with me at length. The in- stallation was painless and thorough. They tested airflow at all parts of our home and made adjustments until ev- eryone was satisfied. “They made various fixes along the way to optimize our furnace, like ad- justing the blower speed to match our Dawn Mroczek is the comfort specialist at GV’s Heating & Cooling in Glenview, IL. In 2007 she moved into the sales position. She is certified in Commercial Air Balancing, Duct System Optimization, and was recognized as one of the “Wonderful Women in HVAC Sales” with Sharon Roberts. She is also the 2020 recipient of NCI’s High-Performance Sales Excellence Award that was presented to her at this year’s Virtual Summit. If you would like to learn more about her Performance Report, reach out to her at ncilink.com/ContactMe. NOVEMBER 2020 17HVACTODAY.COM T emperature is the third step on the path to performance. Since many are already familiar with temperature mea- surement, the path to performance gets easier at this step. However, many of us limit our temperature testing to the equipment and fail to see its impact on the rest of the system. As you move along the path to performance, you’ve already mastered the concepts of static pressure and airflow. Now it’s time to consider temperature at the supply registers and return grilles. These temperature measurements often reveal a significant negative impact on the com- fort of your customers which is critical to your system performance diagnostics. Once you release the true potential of tempera- ture testing, you’ll quickly discover why oversized systems appear to work well, while properly sized systems often cannot provide comfort. TEMPERATURE PRINCIPLES It’s helpful to review some temperature basics before we discuss how it ties into the per- formance path. First, hotter temperatures always move towards cooler temperatures, or hot goes to cold. Second, hotter air rises while colder air falls. For those of you who’ve attended Nation- al Comfort Institute’s (NCI) Carbon Mon- oxide (CO) and Combustion Perfor- mance course (ncilink.com/COTest), you’ve seen how we tie these principles into draft pressure and stack effect. When you measure HVAC tempera- tures, you typically use two temperature types: dry bulb and wet bulb. Dry bulb tem- perature measurements help interpret the amount of heat in the air. It typically re- fers to the temperature you can feel such as when a gas furnace kicks on and warms up the air. Use this temperature when testing heating and cooling systems. You should use wet bulb temperature for cool- ing system testing. This reading accounts for both heat and moisture content in the air. We rarely do much with wet bulb as a single temperature reading. Instead, we use it in com- bination with other measurements, like dry bulb temperature, to determine other air properties such as relative humidity. Then there is something called dew point tem- perature. This is a third measurement that helps us understand at what temperature moisture in the air condenses on a surface. For example, let’s consider an uninsulated met- al duct system in a crawlspace. As the cooling system runs on a humid summer day, the ducts sweat. The duct temperature is lower than the dew point temperature, so condensate forms. As soon as your back brushes against those ducts, you’re soaked. Temperature: The Third Step to Airside Performance By David Richardson TECHNICAL The PATH to Performance: PART 4 We continue with our series of articles detailing the PATH ( P ressure, A irflow, T emperature, and H eat) to Performance. In the first three installments, David Richardson provided an overview of PATH, detailed Step 1: Pressure, and covered Step 2: Airflow. ● Read Part 1 here: ncilink.com/PATH1 (Overview) ● Read Part 2 here: ncilink.com/PATH2 (Step 1: Pressure) ● Read Part 3 here: ncilink.com/PATH3 (Step 2: Airflow). Remember, practice makes perfect. So, as Richardson explains, become proficient in each step before proceeding to the next. In the end, you will be able to deliver the greatest value in service and performance that your customers have ever seen. And that will help you deliver the most well-deserved profits to your bottom line. In his next article, Richardson will address more details on the third step in the PATH: Heat. Stay tuned! The PATH to Performance: A Six-Part Series THIS IS THE FOURTH IN A SERIES OF ARTICLES BY DAVID RICHARDSON DISCUSSING THE PATH TO PERFORMANCE: PRESSURE, AIRFLOW, TEMPERATURE, AND HEAT.18 NOVEMBER 2020HIGH-PERFORMANCE HVAC TODAY need to take further actions. The first step with equip- ment temperature testing is to assure your test locations are ac- ceptable. A simple rule to follow is to place your test ports where the ther- mometer probe cannot “see” the heat exchanger or evaporator coil. It’s also a good idea to avoid testing near any duct leaks or the blower motor. NCI recommends you test equipment sup- ply temperatures in a branch duct close to the plenum. As you measure and interpret equip- ment temperature changes, keep in mind it is always affected by the vol- ume of airflow moving through the equipment. If airflow is lower than specified, temperature change will be high. If air- flow is high, temperature change will be low. Remember, “A” is before “T” in PATH. This is another reason why you should check airflow before you jump to temperature measurement. When you measure equipment tem- peratures, begin with the dry bulb temperature difference or Delta T (∆t) between the air entering and exiting the equipment. Compare your read- ings to the specified ∆t for the equip- ment you’re working on. Gas furnace ∆t is the easiest to find. The nameplate inside the furnace provides the tem- perature rise range. Air source equipment, like heat pumps and straight cooling systems, have a varying ∆t based on various conditions. Heat pump heating ∆t ranges are usually between 10° to 35° depending on the outdoor air tem- perature. The warmer the outdoor temperature, the higher the ∆t. Cooling system ∆t ranges are typical- ly between 16° to 24°. Factors affecting this range are air- flow across the coil, indoor dry bulb temperature, indoor humidity, and outdoor air temperature. If your airflow is within ± 10% of manufacturer specifications and the equipment ∆t is within range, chances are high the equipment is operating as designed. However, just because the equip- ment airflow and temperatures are in range, it doesn’t mean the system will maintain comfortable conditions. This is where system temperatures can help you see through a fresh set of lenses to identify hidden defects. SYSTEM TEMPERATURE MEASUREMENTS When your temperature measure- ment locations move beyond the equip- ment to the registers and grilles, you start to understand how duct system in- sulation influences performance. This test allows you to see the ∆t your cus- tomer experiences in their home or of- fice. Unfortunately, it is usually nowhere near the same as the equipment ∆t. In an ideal world, the equipment ∆t and system ∆t would be the same. How- ever, we put duct systems in some rough locations. They are subject to extreme temperatures that change the condi- tioned air temperatures through them. To account for these conditions, you can measure system temperatures at these common test locations: n The temperature in the farthest supply register and return grille to de- termine worst-case system ∆t TEST INSTRUMENTS Before you can measure tempera- ture, you need quality digital test in- struments capable of measuring to a tenth of a degree (.10°F) inside the duct system. These instruments include: n Digital Thermometer – for gathering heating and cooling dry bulb temperature readings n Digital Psychrometer – for measuring cooling system tempera- tures such as dry bulb, wet bulb, and dew point. Additional air properties such as enthalpy and relative humid- ity are also available. NOTE: Keep fresh batteries handy for your test instruments. Many digi- tal temperature instruments lose ac- curacy when the battery charge is low. Reaction time is also important with any thermometer. They should adjust quickly to changing temperatures. If your thermometer or psychrometer is older and slower, consider investing in a newer model. EQUIPMENT TEMPERATURE MEASUREMENTS Your physician compares your tem- perature reading to a known standard to see where it compares. A healthy person should run a temperature of 98.6°F. If the measured temperature is out of range, it’s an indicator that something could be wrong and further investigation is necessary. Just as a medical professional has an acceptable test location and baseline to compare their readings, so should we as we follow a similar pattern with temperature testing. We need to test in the right locations and then com- pare our temperature measurements to known standards to see where we fall. Only then should we decide if we TECHNICAL This graphic shows where ductwork typically picks up heat gain.NOVEMBER 2020 19HVACTODAY.COM the worst-case system ∆t. First, in cooling mode, find the equipment temperature drop. Subtract the equipment entering air temperature from the equipment ex- iting air temperature. Next, calculate your supply duct temperature gain. Subtract the equipment exiting air temperature from the farthest supply register air temperature. Then, find your return duct tem- perature gain. Subtract the farthest return grille air temperature from the equipment entering air temperature. Finally, add together your supply and return duct temperature gains to find total system duct gain. For example, let’s say you measure a cooling system with a 20° ∆t across the equipment and a 10° ∆t across the duct system. That would be a 50% duct gain (10° ÷ 20° = 50%)! If your equip- ment is rated at four tons, it would be the equivalent of a two-ton unit be- cause of that duct temperature gain. You won’t see this unless you measure system temperatures and equipment temperatures. In heating mode, the principles are the same, but the temperature loca- tions in these formulas flip flop. The most applicable repairs for duct temperature gain are to add duct insu- lation and seal duct leakage. Be careful as you choose from various insulation options available. Some insulation types offer exaggerated promises but don’t perform in the field. OBSTACLES IN THE PATH As you move further along the Per- formance PATH, the obstacles you met with pressure and airflow are the biggest to overcome. If you’ve come this far, it’s all downhill from here. Two of the most common obstacles you will find with temperature are: n Testing too close to a heat exchang- er or cooling coil n Taking too much time between your temperature readings. Both issues can cause your tempera- ture readings to make no sense or look like the equipment and/or the system is operating better than they are. Pay attention to these easy-to-correct obstacles. OUR LAST STEP Heat is the last step on the perfor- mance path. It is the combination of temperature and airflow and the true measurement of installed HVAC sys- tem performance. In the next article, we’ll look at what this step has to offer you and how it moves our industry beyond selling box- es to providing solutions. n The average of three supply regis- ter temperatures and two return grille temperatures to determine average system ∆t (we’ll discuss this concept more in the next article) n At the supply register and return grille of the most uncomfortable room. For your system temperature read- ings to make sense, you’ll need a stan- dard to compare them against. You could aim to duplicate the equipment ∆t, but you will find yourself disap- pointed that you rarely hit that target. A more reasonable goal for a well-insulat- ed duct system should be less than 10% loss of the equipment’s ∆t. That might sound like a lot until you see how hard it is to come in under that target. Here’s how you can figure it out for yourself. DIAGNOSE SYSTEM TEMPERATURE READINGS Let’s say you have a duct system in- stalled in an attic. It is common in many parts of the country for attic tempera- tures to reach 130° to 140°F in extreme summer conditions. Combine that with ducts in the same attic space carrying 55°F conditioned air, and you have a recipe for an uncomfortable building. That’s a 75° to 85°F ∆t (temperature dif- ference)! Ceiling insulation is often R-38 while duct insulation maxes out at R-8. There’s a problem with this thinking. You can use system temperatures to measure duct temperature gains. All you need are four temperature read- ings. Make sure the equipment has been running for at least 10 minutes before testing. Start at the air han- dling equipment and measure sup- ply and return air temperature to de- termine equipment ∆t. Next, measure the farthest supply register and return grille air temperatures to determine David Richardson serves the HVAC industry as a curriculum developer and trainer for National Comfort Institute, Inc. (NCI). If you’re an HVAC contractor or technician interested in learning more about airside performance, contact David at ncilink.com/ ContactMe or call him at 800-633-7058. NCI’s website www.nationalcomfortinstitute.com is full of free technical articles and downloads to help you improve your professionalism and strengthen your company. This depicts the typical locations for taking temperature measure- ments.Next >