by John Proctor, P.E.
What do HVAC contractors need to do to be successful over the next 10 years? There are several areas where an awareness of emerging technologies and customers' changing needs and expectations can make the difference between a good company and a great company.
As homeowners become better educated about their home comfort systems, be prepared to see more insistence on performance testing in the residential market. Homeowners will want to see objective proof that our systems actually perform as they were designed.
So instead of saying "We're installing a 13 SEER unit," we're going to have to sell the value of our knowledge by saying, "We're installing a 13 SEER unit, and then we'll test it to make sure it has the right amount of refrigerant and the right amount of airflow across the evaporator coil."
There's going to be more and more pressure toward these types of performance certifications. We may see a movement toward independent testing companies that inspect a system after installation. Some contractors are going to embrace it and say, "I'm happy to have someone verify that my system works properly." And there are going to be others who are going to be very nervous and upset that somebody is looking at what they've done. Those are likely to be the ones who shouldn't be in the business.
When it comes to properly installing systems, technician certification programs such as North American Technician Excellence (NATE) are helpful, but there needs to be a step beyond NATE. NATE verifies that a technician knew what he or she needed to know to pass the test. The real issue, however, is what people do in the field. Technicians may know the right thing to do, but is that what they do in practice?
Performance certification can take two forms. One is the technological way, in which a black box on a unit informs the homeowner how the system is performing. However, I prefer the human method. Support your technicians. Give them the tools and quality assurance systems that enable them to get the air conditioner, boiler, or furnace working properly the first time, before they leave the customer's house.
The "black box" method has some advantages. For example, it can notify us if something is going wrong with the system. But a technician will still need to come out and fix it. So there's no escaping the human side of the equation, and there's no substitute for a well-trained and well-equipped technician with a quality assurance system that works.
The lawyers may have actually helped us here, by getting people to think about moisture and mold. We now have an opportunity to teach homeowners about moisture, and the fact that less moisture in their homes will make them more comfortable.
Of course, many people think, "If I get a bigger air conditioner, I'll be more comfortable." Unfortunately, there are still a number of contractors who size their systems larger than average -- and on the average, systems are already oversized. Of course, the end result of that thinking is that we can make it 65F in a house, but with a moisture level that's not healthy for the people or the house.
Successful contractors can set themselves apart from the crowd here by carefully sizing their systems. Follow ACCA Manual J and trust the numbers.
Besides getting away from oversized units, we can reduce the airflow over the coil, which will aid dehumidification because the coil will be colder. However, there are real limitations here. If you get system airflow down below 350 cfm, you run the risk of freezing the coil and still not getting enough latent capacity.
I think we will begin seeing regional air conditioners, some with high latent capacity and others with high sensible capacity. Or, better yet, a variable sensible heat ratio machine that can be set up at installation to the local conditions, with adjustments beyond airflow. We really need to change the equipment we provide, particularly for homes where the sensible load is seriously reduced because of high-efficiency windows and low air infiltration.
High humidity situations require an air conditioner that provides a lot more dehumidification than the current units. Something that's not a straight dehumidifier, but has more than 50% of its capacity devoted to dehumidification, yet provides some sensible cooling.
One product I envision would use an air-to-air heat exchanger between the air leaving the evaporator coil and the air entering the evaporator coil. In other words, it would provide sensible cooling to the air before it gets to the evaporator coil. This would cause the air to be much closer to its dewpoint and, therefore, wring out a lot more moisture as it goes through the coil.
A system like that would have the potential to do the job that people increasingly need, especially in today's tightly built houses.
REDUCED DISTRIBUTION LOSSES
Here's what we're seeing at single-family construction sites around the country: prior to the arrival of the HVAC contractor, no one has even considered where the ducts were going to run. I'd love to say that we're going to educate architects and builders to improve this situation, but I haven't seen many signs of it yet. Either we start putting in ducts that don't leak and deliver the right amount of air to the right places, or some of us will have permanent jobs going back and fixing other people's work.
There's a lot of emphasis on duct sealing, as there should be. We also need to look at surface areas, length of the runs, and restrictions to airflow. What we often create today are oversized HVAC systems feeding undersized ducts, and those are horrible combinations.
You can make better duct systems by using shorter runs and paying attention to register selection and placement (anybody remember ACCA Manual T?). Shorter, straighter runs and careful placement of registers will reduce airflow restrictions, which are noisy as well as comfort and efficiency killers.
Let's say we have to move 400 cfm/ton. Doing that against 210-in. of water column is four times easier than moving it against 810-in. of water column. Less restrictions make for a more efficient system, and makes it easier to deliver the air to where you want it.
The efficiency of the duct system affects the efficiency of the "box," and the performance of the box affects the efficiency of the duct system. As an example, look at variable speed air conditioners. If you test the efficiency of the system in a laboratory, the box itself becomes much more efficient when it's run at low speed. The problem is, in a house, the efficiency of the duct system declines. The conduction losses increase. The heat transfer across the duct and its insulation increases when the system operates in low speed. So you have a more efficient box that, ironically, creates a less efficient duct system.
Pay attention to duct systems. Measure both static pressure and airflow. When the airflow comes out too low, it's time (past time, really) to reduce the total static pressure. With a single return system, the most cost-effective solution is often to add another return.
Professionalism. Communication with customers. Appearance. We survey customers of all the contractors who work with us, and the results are quite interesting. Along with being technically knowledgeable and communicating well with customers, putting on booties to protect customers' carpets garners the highest score from customers. It's a little thing, but it's so important to customers.
We're covering it last, but how your technicians represent your company might be the single most important element in a successful contracting company that you will be proud to own. It will only become more important in the future as customers become increasingly knowledgeable, sophisticated, and demanding. We've focused mainly on technical aspects of HVAC systems here, but remember: you can run the most technologically superior operation in town, but it's likely that your success will start -- or end -- with your people.
John Proctor, P.E., is president of Proctor Engineering Group, San Rafael, CA. He can be reached at 415/451-2480 or by e-mail at [email protected]