Koreman-Kreisel residential pond-loop geothermal system
PROJECT: Pond-loop residential geothermal heating and cooling system
GOAL: To reduce use of fossil fuels
The Challenge
Weaning a sprawling 100-year-old house off fossil fuels can be a daunting task. When Anne Koreman and her partner Carolyn Kreisel moved into their 2200 sq ft 100-year-old sprawling farm house in New York's Finger Lakes area in 2004, they knew they had a lot of work ahead of them to make it the low-impact, energy-efficient home they envisioned. Their main concern was staying warm. Like many older homes, theirs had been added onto, somewhat haphazardly, over the course of several additions. The final space was broken up, which made it difficult to distribute the heat evenly and effectively.
At first, they heated with a 40-year-old forced air oil-burning furnace, a circa-1980's wood stove, a propane-fired fireplace, and several electric space heaters. They kept the furnace at 54o and "huddled around the wood stove to keep slightly warm," according to Koreman. Still, they went through 350 gallons of fuel oil, two cords of wood, and "a bunch" of propane and electricity, and their house was still "pretty cold."
The Solution
One of the first things Koreman and Kreisel did was to replace their incandescent light bulbs with compact fluorescents. Then they had an energy audit done on their home. This identified several leaky areas, which they had air-sealed. They also bought new Energy Star-certified appliances and upgraded their wood stove to a new Hearth Stone soap stone stove.
The air-sealing and new wood stove helped keep the house warmer, but it still wasn't enough. So, in 2008, Koreman and Kreisel had a 3.5-ton geothermal heating, A/C, and hot water system designed and installed by GeoTherm, out of Tully, New York. Geothermal is an energy source that is gaining in popularity, in part because of its relatively short payback. It is founded on the fact that, below four feet or so, the temperature of the earth is basically constant, at somewhere between 50o and 60o (closer to 50o in most of NY State). When the outside air is 10o that's considerably warmer; likewise, when it is 90o outside, 50o is pretty chilly. Running tubes filled with water or antifreeze (glycol) below ground can thus feed a building with cold water in the summer and hot water in the winter. A 40o drop or jump in temperature isn't usually enough in itself to heat or cool the building, but utilizing a heat pump, that water (or glycol) can be made significantly hotter or colder with only a modest input of electricity and circulated through a house either in radiant tubes or through a forced air system.
Because they had a one-acre, 10-foot-deep pond on their property, Koreman and Kreisel opted to run the tubes through their pond, thus lessening the amount of digging required. Like the earth four feet down, the bottom of the pond maintains a fairly constant temperature around 50o. Because they already had a forced-air system, they also chose to use a closed-loop design that circulated glycol.
The total cost of the system, including excavation of the track to bury the lines to the house in, was about $19,000. At that time, there weren't any state or federal incentives for geothermal. The incentives have changed each year, but since then there have been incentives similar to those for photovoltaic systems.
At the time they had the geothermal system installed they also replaced most of the existing leaky metal heat ducts with insulated ducts and installed insulated ducts to three additional rooms, cutting down on their need for electric space heaters. The A/C has also been a nice perk. Though they rarely need it, it's basically free with a forced-air system, so they do end up using it on the hottest days. And the added electrical draw required by the geothermal system they offset with a 6.12 kW photovoltaic system.
Results and Future Plans
Koreman and Kreisel say they are very happy with their geothermal system. They are now able to keep their house warmer and save money. Only on the coldest days do they need to use the wood stove. And their needs for cord wood are now so low that they are able to gather nearly all the wood they need off their own property. In their first year, Koreman and Kreisel saved about $1200 in heating costs, even though they kept the house warmer. Even with modest energy priced increases, they forecast their system will pay for itself in 14 years or less.
The geothermal system is just one part of their overall sustainable site plan. Other major features include a 6.12 kW photovoltaic system, a soapstone wood stove, and an electric lawn tractor. For several years, Koreman and Kreisel have proudly shown off their home's renewable energy features as part of the Ithaca-Area Green Buildings Open House, which takes place the first weekend of October each year. They have already inspired several other area homeowners to install geothermal (and photovoltaic) systems, including their immediate neighbors. And the process of identifying problem areas in their home and working to fix them inspired Annie to become a licensed home inspector. You can learn more about her company, Every Square Inch Home Inspections, at www.esihi.com.
More Information
- Download a fact sheet highlighting many of Koreman and Kreisel's efforts to make their home more green here (100 kb)
- More photos of their geothermal installation are available here
Contact:
Annie Koreman
4348 Swamp College Rd.
Trumansburg, NY 14886
ecoannie@esihi.com
607-387-4147
