Correctly sizing, selecting, and installing equipment is critical to proper performance
HVAC systems now come with higher efficiencies than ever, with air-source cooling equipment surpassing the 25-SEER mark and gas furnaces achieving more than 98 percent AFUE. Customers who pay for these highly efficient (and expensive) systems expect them to achieve those ratings and provide superior comfort, and, if they don’t, they are often disappointed and even angry.
When high-end equipment does not live up to consumer expectations, the culprit is almost always improper installation. According to a recent report from the National Institute of Standards and Technology (NIST), an improper installation could increase household energy use for space heating and cooling as much as 30 percent over what it should be, thanks to issues such as improper refrigerant charge, incorrect airflow, oversized equipment, and leaky and/or undersized ducts.
The bottom line: Properly sizing, selecting, and installing HVAC equipment is critical to ensuring energy efficiency and comfort.
GOING BY THE BOOK
The best way to ensure consumers achieve the increased levels of comfort and efficiency they paid for is to follow industry-established guidelines, which is why Joe Tollari, president, Metro Heating & Cooling LLC, Des Moines, Iowa, performs ACCA Manual J, D, and S calculations on every installation. “I was taught by my dad to be as thorough as possible, and that means following the guidelines. We are involved mainly in new custom homes, and I want to give homeowners a custom comfort system. I can’t do that by following rules of thumb.”
That custom comfort system usually involves a 95 percent efficient furnace along with a 14-SEER air conditioner. Tollari typically works with the builder to ensure the system’s properly installed in the home. “For aesthetic purposes, architects like to put the mechanical room on a far corner of the house, which means the air coming from the furnace is cooler by the time it reaches the opposite end of the house. I always make sure the furnace is centrally located and all the ductwork is sealed. Then, when homeowners are just about ready to move in, I test the systems to make sure the calculations in the original Manual J, D, and S are accurate. I prove what I sell, and a lot of homeowners like that.”
Theo Etzel, president/owner, Conditioned Air Corp., Naples, Florida, also uses all ACCA-approved methods for duct and equipment sizing. “We’ve always followed all the best practices from ACCA and ASHRAE, and, to make sure all our installations are up to our standards, we employ a number of supervisors who inspect what we do. In addition, we always pull a permit so there are more eyeballs on the installation to verify we’ve done what’s called for.”
THE FIX IS IN
Etzel is involved in a lot of new construction — both custom and production homes — but he also does a fair amount of high-efficiency equipment retrofits. In those cases, he almost always has to modify the ductwork. “In our area, the ductwork is often chronically undersized. When homeowners want to replace a system with a higher-SEER unit, the undersized ductwork causes problems with static pressure on the return side and/or on the supply side. Typically, we find that both sides need modification to accommodate the higher-efficiency systems. We also always replace the plenums and upsize them when we can.”
And, if homeowners do not want to fix their ductwork before installing a high-efficiency unit, Etzel will simply walk away. “If the ductwork is wrong, we won’t do the job. If we make a mistake, and we don’t change the ductwork, we will go fix it for free. So, instead of fixing it for free, we aim to charge for the proper installation.”
Dan Kayser, production manager, Apollo Home, Cincinnati, said some customers are more willing than others to invest in their ductwork to make sure the system works efficiently. “We operate in a market with a lot of older homes, and, in many cases, there are no return air ducts on the upper level. We’ve found that variable-speed equipment can help partly resolve some minor ductwork issues if the customer is not interested in running new supply or return ducts to poorly performing spaces. It’s also not uncommon to find newer homes with undersized duct systems. In those cases, we’ll enlarge returns and add supplies, as necessary, to allow the system to move the proper amount of air.”
Many times, Tollari finds that ripping out all the ductwork and starting over is the only way to solve the problems a customer may be experiencing with his or her existing HVAC equipment. “I’ve also torn out lots of brand new equipment and replaced everything with smaller equipment. While customers are generally not too happy about this, it’s necessary sometimes because the equipment is so incredibly oversized, the ductwork is undersized, or the building envelope has problems.”
In those situations, it’s difficult to convince customers you are trying to help them, as they are already feeling betrayed by the previous installing contractor. “Here I come, telling them some of the same things the previous guy told them, yet I’m adding duct renovations into the equation,” said Tollari. “It’s very hard to gain their trust, but, when they see us pull out all our equipment and start testing the house as a whole, they realize we’re different. Once we’re done, they all comment on how their comfort is at a whole different level.”
Ultimately, there will always be contractors who put in high-efficiency systems without sizing them correctly or fixing problems with the existing ductwork. The good news, said Etzel, is that he gets more business by fixing these systems. “We’re one of the few in our area who do it right the first time. A lot of people will install high-efficiency equipment that doesn’t result in energy savings or better comfort, but that’s not us. We’re going to do it right and stand behind what we do, and, if we do it wrong, we’re going to make it right — period.”
Publication date: 6/22/2015
For correctly sized equipment with proper installation contact Cold Craft, Inc., a NATE Certified, Diamond Certified Contractor in the Silicon Valley. 408-374-7292 license # 631837