PRESQUE ISLE, Maine — The presence of a 190-ton truck and crane system raised eyebrows at the Aroostook Centre Mall this week, but mall officials said Friday they plan to heighten the facility’s ability to reduce the mall’s carbon footprint.

The mall is in the process of upgrading its heating, ventilation and air-conditioning systems to make the mall “greener.”

“It is a great change and one that will have a tremendous effect on how we impact the environment,” Patti Crooks, the mall’s general manager, said Friday.

The mall has converted eight 20-ton, electric-fired HVAC units into gas-fired units. The $300,000 conversion came after mall officials teamed with the Northern Maine Development Commission to conduct an energy audit that found the mall was using a great deal of electricity.

“And, of course, electricity is expensive,” she said. “But now, we will be using propane to heat and cool the mall, which will cost less. This will make for a greener mall and will enable us to reduce our carbon footprint.”

The 600,000-square-foot Aroostook Centre Mall opened in November 1993. At the time, Crooks said, the building was built to be as energy-efficient as possible. But nearly 16 years have gone by, and additional ways to be greener are coming to light every day.

“We have made quantum leaps over where we were 15 years ago,” she said Friday.

The conversion process has been painstaking but positive, according to Crooks. The massive crane has been helping tow and lower equipment onto the roof of the mall. Mechanical Services Inc., which has an office in Easton and other locations across the state, is performing the work. Efficiency Maine also has been involved in the process.

“In the past, our only source of heat was electric,” said Crooks. “In the summer, we used electricity for air conditioning. We are going to see a difference in expenses for heating and cooling. We estimate we will see a payback in three years.”

Crews are working on hooking up the air conditioning to the converted units, and the project should be completed in a few weeks.

“This is something we have wanted to do,” Crooks said Friday. “We want to be environmentally conscious.”