Mitsubishi Electric HVAC installed Vermont’s first City Multi VRFZ system in historic Hill Hall, one of 16 Victorian-era mansions that are now Champlain College residence halls in Burlington, Vt.
BURLINGTON, Vt. - Hill Hall is one of 16 Victorian-era mansions that are now Champlain College residence halls. Built by A.B. Fisher in 1884 for the Dunham brothers (Vermont lumber barons), Hill Hall today is a coed dormitory for 40 students; it has 13 rooms for two to four students each on four floors.

The college's board of trustees authorized an air conditioning upgrade every other year. With a first-ever budget approval for air conditioning in an existing dormitory, Holly Mussatti, director of physical plant, challenged her staff to fast track an installation to be up and running in time for the 2004-05 academic year

She said she chose Hill Hall because it was in need of total rehabilitation. Only the newest dorm on campus (2003) had been built with air conditioning, and this would be the first retrofit to be installed in-house by her staff.

Mussatti said she researched current HVAC systems to accommodate this historic building. Contractor Steve Hayden of Mountain Air Systems, South Burlington, recommended that she look into a ductless two-pipe system.

Choosing The System

"When Holly and I first spoke about installing air conditioning in Hill Hall, she told me she was looking for a system that could provide individual temperature controls, was quiet, had minimal outdoor equipment, looked nice, and could be installed in an old building with minimal space," Hayden said.

This 100,000-Btuh City Multi R2 Series outdoor condensing unit was installed under the fire escape of historic Hill Hall.
"I had just discovered the City Multi® VRFZ System a couple of weeks earlier," he continued. "This system would provide everything Holly was looking for and more, such as the simultaneous cool/heat option. Soon after, we had the system installed and running. The installation and startup went very well." The City Multi variable-refrigerant-flow zoning (VRFZ) system is manufactured by Mitsubishi Electric HVAC (MEHVAC).

"The heat exchanger in the outdoor unit reminded me of my old days installing boiler manifolds," said Mussatti, formerly a certified plumber. "I was impressed by the fact that a single outdoor condensing unit requiring only a small bit of real estate was all I needed to run 16 8,000-Btuh wall-mounted indoor air-handling units.

"With no costly ductwork accessories and labor involved and serious interior limitations posed by the 121-year-old structure, all I needed was a 3-inch hole in one wall to bring in the wiring and piping from outdoors," she said.

"The installation went very smoothly, and we were able to open on time 70 days later." The installation was completed by August 2004.

Hill Hall, a Victorian-era mansion that serves as a residence hall for Champlain College, was the first dormitory to undergo air conditioning retrofit.
"We were also impressed with the ability to use the system as a backup for our gas-fired boilers," she said. "Vermont has high electric rates, and this backup helps us conserve energy costs."

MEHVAC area manager James (Jeb) Bates helped design the Champlain College system. "Buildings such as Hill Hall each have unique temperature requirements based on use, age, construction, and even exposure to the elements," he said. "Some spaces may need heating while others need cooling."

The R2-Series is made up of a condensing unit, branch circuit controller (BC controller), indoor air handlers, and remote or central controllers. "To simultaneously cool and heat, the BC controller acts as the heart of the system," the manufacturer explained.

The controller manages refrigerant gas and liquid and directs it to the air handlers requiring cooling or heating. The system recovers heat from one space and sends it to another.

A single outdoor condensing unit runs 16 8,000-Btuh wall-mounted indoor air-handling units.
The systems' outdoor unit uses an inverter-driven compressor with variable-frequency drive technology. The variable-capacity indoor units are controlled by electronic expansion valves that are said to allow only the amount of refrigerant into the air handler that is needed to condition the space.

The system also offers a variety of ducted or ductless air handlers such as ceiling-recessed, ceiling-concealed, floor-standing, floor-standing concealed, and wall-mounted models.

Hayden pointed out that the City of Burlington has very strict zoning laws to help preserve the turn-of-the-century look in all building renovations. "This system is a perfect solution for providing air conditioning in buildings with no space for ductwork and large fan systems," he said.

"We have not had to call Mountain Air once over the past 12 months," said Mussatti. "In fact, the board of trustees has been so impressed that it has designated Hill Hall the ‘Admissions Hotel' for visiting high school guidance counselors during the summer months."

For more information, visit

Publication date: 08/08/2005