Big Build, Bigger Challenge

SMACNA contractors do approximately 75% of all new residential construction in the St. Louis, Missouri, market, so Welsch Heating and Cooling of Maryland Heights, Missouri, had an edge when it was time to bid a unique single-family home. “One of our contractors was the successful bidder for the project and assigned the work to us. Knowing our background and knowing that we could handle such a large project, they were glad that we bid it and glad that we could participate in the work,” says Paul Heimann, Vice President and Comptroller of Welsch Heating and Cooling. 

The massive 14,300-square-foot, ranch-style home has 28 tons of cooling, about seven times as much as a typical St. Louis home. Welsch took part in every step of the job, joining the complex planning process in June 2021. “We sat through several meetings with the owner, the general contractor and the architects,” Heimann says. “They even had a mechanical engineer. Our portion of the HVAC planning process was to go over how they wanted the house zoned, where they wanted the duct work to run, what kind of equipment they wanted to use, as well as energy efficiencies.” 

The owner prioritized energy efficiency, so they decided on geothermal heat pumps. Welsch used two water-to-water units for the radiant in floor heating and four water-to-air units for the forced air systems. “We got that bidding and pricing done to make sure that we met the homeowners' expectations,” Heimann points out. 

The high CFM kitchen range hood in the luxury kitchen required careful consideration. “Those hoods can suck all the air out of the house, so we installed a heated makeup air fan as well as an Energy Recovery Ventilator for fresh air ventilation,” Heimann says. “Sometimes we see how the air will be extracted from the house and how it's coming in, and we have to provide for that.” 

Welsch also compensated for extreme humidity changes. “In St. Louis, we have very dry winters, so we install humidifiers to keep the air moist in the winter, but we have humid summers, so we dehumidify the air to mitigate moisture problems. In the summer, if you're bringing in outside air, and not treating that air accordingly, you're bringing very moist air to very cold ductwork. It’s going to make everything sweat.”

Welsch purchased round pipes and elbow for the project but fabricated all duct in house. “The gauge we use depends on the size of the ductwork, because if the metal is too big, it gets floppy and makes noise,” Heimann says. “We use anywhere from 22-gauge to 28-gauge galvanized steel, depending on the application. It’s like a jigsaw puzzle. We measure and fabricate every piece to our specifications, so it fits properly, and it looks great at the end.” 

Welsch custom fabricates 8-foot joints to save time on site. “We use 8-foot joints instead of the usual 5-foot joints, because that means fewer joints to connect as we're doing a house,” Heimann says. “To comply with local codes, we have to seal all of those joints, so the fewer seals we have, the less time we spend sealing.” 

For most residences, the huge HVAC system would have been Welsch’s biggest responsibility, but the owners wanted a unique exterior for their dream home. “Not only did we do the HVAC, but we also put a complete metal roof on this house, and the siding of the house was all made of metal,” Heimann says. Welsch fabricated and installed a 22-gauge Rhein Zink metal roof and siding on the home. “We basically wrapped the entire house.” 

Welsch organized the work as two separate jobs. “We bid on the heating and cooling, and then we gave them a separate bid for the architectural sheet metal,” Heimann says. Two Welsch foremen attended the planning meetings. “We had one foreman in charge of the heating and cooling aspect, and we had another foreman in charge of our architectural department. He understands roof pitches and flat roofs, and how water drains.”

Welsch purchased a specialized double seamer for the architectural side of the project. “We needed a smaller seamer than any we could rent,” Heimann says, “so we did some research and bought one, which saved a lot of work hours in the field.” 

Welsch often completes new homes in nine to 12 months, but this project took about 18 months. “We put our first person on the jobsite in February of 2023, and we finished it at the end of last year,” Heimann says. “We had 4,000 work hours on this project, 3,300 architectural hours and 700 HVAC hours. Only about 100 of those hours were in the shop.” 

“With any project of this size, the biggest challenge is coordinating with all the other trades,” Heimann says. “We don’t want to be in their way, and they don't want to be in our way. With the exterior sheet metal work on this particular home, the weather was also a factor. It’s always a challenge to tackle such a big job, but one we take great pride in accomplishing.”