Above and Beyond
A major component of the renovation was the geothermal heating and cooling system, which would not only mitigate the mansion’s astronomical energy bills, but also could be hidden within the property’s existing features—a requirement of historic preservation boards.
Poccia donated his team’s time and charged only for the cost of materials— about one-third the typical cost. “I did put in a couple pieces of high-end equipment that were used and refurbished; both were in full working order and needed basic cleaning and servicing,” he says.
Although Poccia was told he could place the geothermal system’s wells wherever he liked, he opted not to disturb the mansion’s driveway, mature trees and garden. Four 500-foot-deep vertical bores were drilled in the front lawn. “We made all the piping connections 6-feet-below ground, then backfilled and finish graded with seed and hay,” Poccia recalls. “Nobody would ever know the bores are there.”
The closed-loop geothermal system, which pumps a water and antifreeze solution, takes advantage of the earth’s fairly consistent temperature of 55 F. In the winter, the ground heats the fluid inside the pipes; then, a circulator pump moves the fluid into a heat exchanger inside the geothermal HVAC equipment. The geothermal equipment then transfers the energy to air-handling units that pump heated air through the facility. In summer, the geothermal system pulls hot air from the house, replacing it with air cooled by the earth. The system does not require combustion, which mitigates exhaust gases and maintains good indoor air quality.
To condition the first floor, Poccia installed mechanical equipment in the basement and used what was left of the old-fashioned steam system to create a duct layout. “Whoever built the house was obviously very affluent,” Poccia says. “On the first floor, the house has large bronze floor grates, so I modified the duct system to utilize those floor grates.”
Poccia discovered a few unused bronze grates inside a crawlspace. They were cleaned and utilized for additional ducting in first-floor areas that previously had been unconditioned.