< Previous10 DECEMBER 2024HIGH-PERFORMANCE HVAC TODAY By Adam Mufich TECHNICAL Measuring room pressures with a DG-8 manometer me. There was one central return in the hallway and no jumper ducts or transfer grilles in the bed- rooms. Apparently, the installation contractor did not remember that one CFM in equals one CFM out. WHAT YOU SUPPLY, YOU MUST RETURN Room pressurization issues can arise if a room has air supplied to it without a path for the air to travel back to the return. When I brought this to my brother’s attention, he recalled something the builder said during his final walk-through of the home. He was told, “Make sure you don’t shut the bed- room doors at night.” I couldn’t believe the build- er would suggest not using the bedroom doors. This statement blew my mind. However, if you think about it, this suggestion makes sense. The builder must have learned from previous comfort complaints that by keeping the doors open, the complaints would go away. He stumbled across the fact that the building is part of the duct system, and the interior doors are the biggest dampers in the system. This was good advice because the multiple sup- ply registers and a lack of return air pressurized the primary suite. A ROOM IS AN EXTENSION OF THE DUCTS When you close a door to a room that has a sup- ply duct and no return path, you take air from the main body of the house and dump it into an iso- lated portion of the home. That isolated room be- comes pressurized. Think of the room as a duct and the door as an endcap. In this scenario, the room could have measurable static pressure. The only difference is the scale used to measure room pressures. A few years ago, my brother bought a new construction home near New Orleans, LA. He was nervous about the quality of his new home, but more specifically, the HVAC equipment and installed duct system. There were news stories about homeowners su- ing local home builders because of mold issues. After his family moved into the house, he asked me if I could come down and analyze his HVAC system. It just so happened that the Air Conditioning Contractors of America (ACCA) was having a con- ference in New Orleans that year, so I flew down and killed two birds with one stone. When the conference ended, I inspected my brother’s HVAC system. What I found surprised Don’t Pressurize Your High-Performance HVAC CustomersDECEMBER 2024 11HVACTODAY.COM Figure 1 shows ductwork in the crawlspace leaking return air, which causes a house to become pressurized. Figure 2 depicts ductwork in the crawlspace leaking supply air, which causes the house to become pressurized. depressurized if the door was closed while the dryer was running. The dry- er depressurized the room in two dif- ferent ways. The dryer sucks air out of the room through its exhaust. He has a natural gas dryer, which re- quires a fuel-air mixture to complete the combustion process. The air in that mixture must come from the laundry room, which lacked an air path for the dryer. This can lead to a dangerous situation. Air leak- ing in from the garage could contain fumes from chemicals, gasoline, or even worse, carbon monoxide from auto exhaust. My brother also has a tankless wa- ter heater installed outside next to his condenser. I am from the Chicagoland area, and our winter climate would the rest of the house. This is another variation of HVAC-induced infiltration. BUILDING PRESSURES IMPACT IAQ Air leaking into the home from out- side won’t always come from ideal ar- eas. It can leak in from dirty areas like a crawl space or an attic, which could hurt the home’s indoor air quality. Infiltration can also cause high hu- midity in a house by sucking in humid outside air. Understanding building pressures can help a technician solve IAQ issues by stopping the problem at its source. SAFETY BECOMES A CONCERN My brother’s laundry room, which shares a wall with the garage, became Instead of using inches of water col- umn, we use a smaller scale called pas- cals (Pa). To give you an idea of how small a pascal is, 0.1 inches of water column (in-w.c.) is equal to 25 pascals. The goal should be to have no mea- surable pressure difference between a room and the rest of the house. In the real world, three pascals have become a universal maximum pres- sure differential (ΔP). Although, there are times when three pascals is even too much of a ∆P. A pressurized room could cause a reduction of supply airflow to it. This occurs because the door adds resis- tance to that supply duct. By adding resistance, it effectively creates an in- crease in the equivalent length of the supply duct. This is why a closed door can reduce airflow to a room without a return. If a room is pressurized, some of that air is taken from the rest of the home. This situation leaves the main body of the house depressurized with reference to the outside. A house operating under negative pressure will suck in outside air. This action is known as infiltra- tion. The HVAC system causes infil- tration in this example. Did you catch where I said, “A closed door CAN reduce airflow to a room without a return?” If the room has gaps, cracks, or holes connected to the outside, this can be a path for air to flow out of the room. The problem is the air isn’t flowing back to the equipment. Instead, it is forced outside the building envelope. If this occurs, the house will also be- come depressurized. In this situation, there will be little or no measurable pressure difference be- tween the room without a return and 12 DECEMBER 2024HIGH-PERFORMANCE HVAC TODAY TECHNICAL leaking into or out of the basement. If this happens, the air doesn’t move into or out of the room as intended. At a minimum, this could create a comfort complaint. Leakage inside a home can cause room pressure issues that can increase infiltration and/or exfiltration. In the worst-case scenario, the pressures can interact with the draft of a gas appliance and create a dangerous environment by introducing carbon monoxide into the home. WHAT’S THE SOLUTION? Furthermore, my brother’s blow- er motor speed was set too high, thus moving too much air. By reducing the fan airflow, I reduced room pressur- ization issues. He still needs to install a return duct in his primary bedroom, and I suggested he install jumper ducts for the smaller bedrooms and the laundry room. Sizing a jumper duct or transfer grille can be tricky. Last year, I wrote an article for HVAC School called “What Airflow Goes Around Has To Come Around.” In this article, I examined differ- ent methods of sizing transfer grilles and jumper ducts. Since that arti- cle’s release, The Energy Conser- vatory created a product called The Roomulator ® . It is a card that gives guidance on passive return sizing. The card instructs you to measure the room pressure and then slowly crack open the door until you reach an acceptable ∆P, then measure how much the door is open. This is enough data to size a passive return properly. A QR code on the front of the card links to a video with detailed instruc- tions on how to use it. You will need a are in a vented attic, so combustion air for the equipment wasn’t a con- cern. However, when you consider duct leakage, that’s another story. A leaky return duct in- stalled outside of the en- velope is sucking in out- side air, which can lead to the house becoming pres- surized. When this oc- curs, there is too much air in the home, and it is forced out through gaps, cracks, and holes. This is called exfiltration. If a supply duct leaks outside of the envelope, air meant to stay inside the home is forced out. Supply duct leakage can depressurize a house; another form of HVAC-induced infiltration. Ductwork inside the building can be just as bad depending on where it leaks. In Chicago, most duct systems are in basements. There is a misconception that duct leakage inside the envelope doesn’t matter. Well, it does matter. The first thing to consider is air never allow for this installation ap- proach. Removing a gas-fired appli- ance from a home makes things a lit- tle easier. In the Midwest, it is common to see laundry rooms with a natural draft water heater installed next to the ga- rage. If the builder had done so in my brother’s home, the room’s negative pressure could have caused a natural draft water heater to backdraft and spill carbon monoxide. RETURNS BLOW, AND SUPPLIES SUCK My brother’s furnace and ductwork Pictured above: a jumper duct (passive return) in an attic. Photo credit to Michael Cianfrocco. Sizing a passive return with the Roomulator.DECEMBER 2024 13HVACTODAY.COM TECHNICAL including building pressure issues. Learn to solve these problems and unlock another revenue stream with- in your business to put you one more step ahead in your marketplace of your former competition. combustion air issues or duct leak- age. I recommend attending Nation- al Comfort Institute’s Carbon Mon- oxide training to learn more about combustion air. You can measure duct leakage with either a TECDuct Blaster® or by taking a known airflow measurement at the equipment and subtracting the measured airflow at both the grilles and registers. The difference between the two measurements is live duct leakage. When you start to think of a home as part of the system while consider- ing its pressures, diagnosing safety, health, comfort, and efficiency issues becomes much easier. Measuring is always the first step to identifying HVAC-related problems, micro-manometer like the DG-8 that measures pressure in pascals. The Roomulator will help you size passive returns but will not address Adam Mufich serves the HVAC industry as a curriculum developer and instructor for Na- tional Comfort Institute, Inc. (NCI). NCI specializes in training that focuses on improving, measuring, and verifying HVAC and Building Performance. If you’re an HVAC contractor or technician interested in learning more about air sealing benefits, contact Adam at ncilink.com/Con- tactMe . NCI’s website www.nationalcom- fortinstitute.com is full of free information to help you improve your professionalism and strengthen your company. A technician begins testing for house pres- surization using a TEC Duct Blaster®.14 DECEMBER 2024HIGH-PERFORMANCE HVAC TODAYDECEMBER 2024 15HVACTODAY.COM It’s about helping fellow contractors and foster- ing community and mutual growth. “How can I help,” is a mantra I live by – for my customers and colleagues. WHY IS SERVANT LEADERSHIP SO IMPORTANT? To me, servant leadership is crucial. It empha- sizes the importance of supporting and devel- oping others, creating a culture of collaboration and continuous improvement. The sense of pride and obligation drives me to continue helping others succeed faster by sharing my experiences and insights. This approach has always been at the heart of my work, whether mentoring a young profession- al at one of NCI’s High-Performance HVAC™ Summits or assisting a peer in troubleshooting a challenging job. STARTING OVER FOCUSED ON TRAINING AND EDUCATION I recently started my own HVAC company, and that process provided me with fresh context for applying these principles. With over 35 years in the industry, I believe learning and training are lifelong pursuits. Regardless of their experience level, everyone has something valuable to offer. This mindset contrasts with the traditional hi- erarchical structure of many companies, where employees often feel like numbers. My compa- ny focuses on empowering employees, appreciat- ing their contributions, and providing continuous training. This empowerment, in turn, ensures they take care of customers. And that fosters a cycle of mutual growth and success. One of the most fulfilling aspects of my career is watching former co-workers and employees start I was honored and surprised as a recipient of the Rob Falke Servant Leadership Award from National Comfort Institute (NCI) in 2023. This prestigious award, named in honor of my mentor, Rob Falke, was a moment of great personal significance. He had an uncanny ability to provide clarity and calm in our conversations, and his influence on my career is profound. The recognition for my efforts to give back to the HVAC industry was a tribute to the many les- sons I learned from Falke and the broader NCI family. I didn’t initially identify with the concept of servant leadership. But upon reflection, I re- alize it encapsulates my approach to the industry. For me, being a servant leader means contribut- ing to the industry that has given me everything. I‘m from the High-Performance HVAC ™ Industry: How Can I Help? By Mike Greany LEADERSHIP Robin Falke (second from left) joined David Richardson (left) and Dominick Guarino (right) to present the inaugural Rob Falke Servant Leadership Award in honor of her late husband, NCI President Rob Falke. The winner was Michael Greany (second from right).16 DECEMBER 2024HIGH-PERFORMANCE HVAC TODAY about building a legacy. It’s about making a positive impact on others, whether it’s through direct mentor- ship or fostering a culture of continu- ous improvement. The annual NCI summit is a testa- ment to this, where discussions and shared experiences help everyone grow. Meeting new, talented profes- sionals and exchanging ideas keeps the spirit of servant leadership alive. The future of my company is bright, with ambitious goals and a commit- ment to excellence. We’re focusing on effective marketing and using technol- ogy to enhance our services. Despite being a small operation currently, with just one truck and a close-knit team, our vision is to grow significantly, aiming for substantial revenue growth in the coming years. THE HIGH-PERFORMANCE APPROACH Our business model emphasizes providing options to customers and focuses on system performance rath- er than just equipment replacement. This approach differentiates us from other HVAC contracting firms and en- sures long-term customer satisfaction. We turn satisfied customers into our best advocates by consistently deliver- ing high-quality service and maintain- ing strong relationships. The HVAC industry is challenging. Over the years, I’ve interviewed count- less employee candidates, many lack- ing the practical experience or resil- ience needed for the job. The reality is that this industry re- quires a unique blend of technical their own successful businesses. For instance, one former colleague established his own HVAC compa- ny nearby. We don’t view each other as competitors but as colleagues, each contributing to the industry’s overall health. This perspective on competition and collaboration has been a cornerstone of my professional philosophy. SERVANT LEADERSHIP’S TANGIBLE BENEFITS Running a business grounded in servant leadership has tangible ben- efits. It creates a work environment where employees feel valued and sup- ported, leading to higher retention and job satisfaction. For our customers, it means receiving exceptional service from a team com- mitted to their well-being. The princi- ples of servant leadership — prioritiz- ing others, focusing on growth, valuing teamwork, and coaching — align per- fectly with my approach to business. When I think about it, I realize that servant leadership has always been Running a business grounded in servant leadership has tangible benefits.DECEMBER 2024 17HVACTODAY.COM LEADERSHIP fostering a culture of support and de- velopment, and always striving to pro- vide the best possible service to our customers. As I continue to build my compa- ny, these principles will remain at the core of everything we do, driving us towards a future of sustained success and positive impact. tinue growing while maintaining the principles of servant leadership. To achieve these goals means investing in our team, providing ongoing training, and fostering a culture of collabora- tion and mutual support. It’s about building a company where everyone feels valued and empowered to contribute to our success. When people come to me – wheth- er they are co-workers or customers – and ask questions, I answer with a question: ‘How Can I Help?’ That, in my opinion, is the backbone of a ser- vant leader. These attributes come from my fa- ther, Ed, who taught me and my sib- lings about work ethic and service. Servant leadership is about recog- nizing the value in every individual, skills, problem-solving abilities, and a genuine desire to serve others. Those who thrive often embrace these chal- lenges and are willing to learn and adapt continuously. SERVICE LEADERSHIP AND STRONG PARTNERSHIPS One of the key strategies I’ve em- ployed is leveraging solid partnerships with suppliers like R.E. Michel. Cre- ating such partnerships ensures we have the best materials and equip- ment and allows us to focus on what we do best — serving our customers. By not haggling over prices but in- stead focusing on service and reliabil- ity, we’ve built strong relationships that benefit our business and clients. As I look ahead, the goal is to con- Mike Greany owns ASAP Plumbing, Heating, and Air Conditioning in Corona, CA – a compa- ny he founded in 2024. Before that, Greany was the service manager for All Pro Heating in Ontario, CA, and then the residential service manager for Air Rite Air Conditioning and Refrigeration in Huntington Beach, CA. He also owned a small plumbing company before that. To reach Mike, click on ncilink. com/ContactMe.PURCHASE TEST INSTRUMENTS AND ACCESSORIES Duct Optimization is based on measurements, not assumptions and guesses. So, before you can optimize a duct system, take an inventory of your test instruments. It’s likely you already own some or all of the items you need. Some are more expensive than others and require an investment. The items you need are: z A static pressure test kit zDigital psychrometer probes z Digital TrueFlow ® Grid zAnemometer (hot-wire and/or rotating vane) zAir balancing hood z Report options (to capture results). If you’re unsure where to begin, start with a static pressure kit and get comfortable with it be- fore making a big investment. MASTER AIRSIDE TESTING AND DIAGNOSTICS Before any testing begins, you need to gather basic system information, perform a visual in- spection, and install test ports. If you haven’t yet mastered these skills, start now. Everything from this point depends on correct- ly performing these tasks. There’s no reason to delay with apps like measureQuick ® that sim- plify the process. Static pressure measurement is the first airside testing skill you need to know how to per- form. Start with total external static pressure (TESP) since it indicates overall system health. Additional pressure measurements, such as fil- ter pressure drop, coil pressure drop, and duct pressures identify restrictive duct system com- ponent(s). The highest measured pressures A frequently asked question we get at National Comfort Institute (NCI) is, “What skills do we need to optimize a duct system the right way?” To shed some light on this question, here’s an overview of seven essential skills I believe you need. As you read, you’ll notice not all the skills list- ed are technical. While in no specific order, both technical and non-technical skills play an equal role in Duct Optimization. Unless you account for these skills, your chanc- es of success diminish. Seven Essential Steps You Need to Optimize a Duct System By David Richardson TECHNICAL Photo above shows how an air balancing hood works. This is one of the essential tools necessary for you to do duct system optimization work. 18 DECEMBER 2024HIGH-PERFORMANCE HVAC TODAYIf they decide to go with further test- ing, you’ll need to measure delivered airflow into and out of each room. You’ll need an air-balancing hood and anemometer for these duct measure- ments. Make sure you know how to use these test instruments and under- stand the factors that influence them. It’s also a good idea to compare supply register and return grille tem- peratures to those measured at the equipment. This diagnostic test helps identify missing or inadequate duct insulation. USE BEST PRACTICES FOR DESIGN AND VERIFICATION Before you optimize any duct sys- tem, make sure the equipment is sized correctly. Unless you enjoy owning nightmare jobs, I recommend you avoid Duct Optimization on oversized equipment. If the equipment is over- sized (and it usually is) this is a great time to recommend upgrading to the proper size. This is also a great time to make sure you understand and can apply the principles found in ACCA Manu- al D. It’s the HVAC industry standard for duct design. Start in the appendix for some great information to understand important duct system principles to ensure you meet equipment design specifications. When sizing an existing duct sys- tem, few contractors have the free time they need to reverse engineer an existing installation. Experience shows that field instal- lation conditions rarely result in a well-performing duct system. If the duct system design was bad from the beginning, it needs an upgrade. Test the system once work is com- plete to verify that your design meth- ods work. That’s where the rubber meets the road. It doesn’t matter how good your design skills are, unless you verify with measurements, you’re just guessing. FOCUS ON INSTALLATION DETAILS It’s easy to forget that your install- ers control airflow. They’re the ones in are where you want to focus your attention. Once your static pressure measure- ments are complete, add fan airflow to your skill set. You have two options depending on the test instruments you own. The first and easiest option is to es- timate fan airflow with a fan table. You can get this reading quickly with the operating fan speed and manu- facturer’s fan table for the air-moving equipment. The second and most accurate op- tion is a direct fan airflow measure- ment using the Digital TrueFlow Grid. At this point in testing, the custom- er has a decision to make. If they want to proceed with Duct Optimization, you’ll need more information to fur- ther diagnose the duct system like de- livered airflow and temperatures into the living space. Do not perform this type of as- sessment for free or as part of a sales call. The customer should pay for this service and be fully involved in the testing process. DECEMBER 2024 19HVACTODAY.COMNext >