University of Texas at Austin-The Tower

Not all air handling unit installation sites are uniform; some require access to interstitial space, while others require elevator access. Some are rectangular, while others are polygons. Still others need to be built around existing walls, pipes or columns.

However, retrofitting an air handling unit in what may seem like a difficult or even impossible space is now easier than ever. For example, the University of Texas at Austin Main Building, also known as The Tower, is a 28-story structure with an air handling unit on the 25th floor, immediately below the university president’s office. The unit was built on a difficult site behind the clock on the tower, says John Kolar, vice president at Air Enterprises, which installed the unit.

“The tower is the namesake of the university and is what everyone looks to as the symbol of UT, so the university wanted to make sure the unit was installed without damaging the structure,” Kolar says. “There was a 3-by-3-foot elevator to get something the size of a school bus up there. And it’s also a main pathway of the campus, so we couldn’t have large rigging because of the risk of dropping something on the students below.”

The unit was constructed on site with simple rigging and elevator access during the campus’s two-week holiday break and was installed by the start of classes.

This example illustrates many of the essential points of retrofitting, Kolar says. Keep these tips in mind when considering or engaging in retrofitting.

  • Have a single point of contact. Choose a company that takes responsibility for the entire project. Having multiple contracting entities can result in a blame game when problems arise on site. The company should also have a representative on site supervising the installation.
  • Employ creative solutions. Your air handling unit provider should be able to design for difficult situations, such as the University of Texas tower, with unique processes and creative engineering. There is always a solution, and you shouldn’t have to dismantle the building to find it. “When most people think of air handling units, they think of a rectangular box, but it doesn’t have to be that way,” Kolar says. “Units can be built to fit the space.”
  • Install a quality product. A quality unit that is made of aluminum won’t rust, rot or corrode. The result is less maintenance, which is especially important on a site with difficult access. Ideally, the unit should last the life of the building; the life expectancy of a modular steel unit is 15 to 20 years, while a custom steel unit is 25 years. An aluminum unit, however, has a life expectancy of 50 years. In addition, ask what kind of seals the company uses and what percentage of leakage it achieves. The industry standard for on-site leakage is 3 to 6 percent, but some companies can achieve 0.5 percent.
  • Look at the cost. An aluminum unit may cost more upfront, but when compared to energy savings and repair or replacement costs, it saves money in the long run. Also make sure the unit has a lasting warranty.

Build on site. This is especially important for a retrofit because it eliminates costly, disruptive demolition and logistical headaches due to expensive crane or helicopter permits when bringing an already-built unit to the site. Make sure the unit has the same quality and warranty as a factory-built unit. “It is important that you don’t factory build something, take it apart, then put it back together,” Kolar says. “When you do that, it is never as good as when it was built the first time, no matter who designed it or put it together.”