Geothermal a perfect fit for this Kiel home
The Objective: Update and improve the energy usage of a beautiful historic home by installing the most efficient geothermal heating and cooling system available.
Home Size: 3,500 Square Feet
Unit Type: 7 Series
Number of Units: 1
Loop Type: Horizontal
Alan Blum describes the drive down the quarter-mile gravel road that leads to the home he and wife Cathy are renovating as a drive back in time.
“As you come upon the fieldstone homestead and see the 100-plus-year-old black walnut tree growing in the front yard, you feel as if you’ve stepped back into the Civil War era,” he said. “The ambiance is just spectacular.”
And that’s why the Blums are looking forward to completing renovations to the 3,500-square-foot home and settling in. “We’re eager to live there permanently, but also willing to take our time and do what’s necessary to ensure we end up with a home that’s comfortable to live in, energy efficient and respectful of the environment around us,” Blum noted.
And so began a top-down renovation, starting with the attic and second floor, while incorporating a groundup geothermal heating system that relies on steady temperatures just beneath the earth’s surface. It provides energy-efficient heating and cooling to the home, while preserving its historic charm.
Located in Kiel, Wis., the 1867 homestead sits on 14 acres of property. When the Blums purchased it, the house boasted its original windows, 30-inch uninsulated stone walls and drafty doors.
“All of those features were charming but also terribly inefficient when it came to keeping the house warm,” said Blum. Add this to the propane gas furnace that most likely needed to be replaced, and Blum was in the market for a new approach to heating and cooling the home.
His first inclination was to seek advice from Dan Walsdorf, part owner along with Sean Steffes, of Advanced Custom Geothermal in Kiel. Walsdorf had serviced the propane furnace in the home.
Arriving at Walsdorf’s place of business, both Blums were delighted to notice the company not only advertised its geothermal capabilities, but also used a geothermal system to provide heating and cooling to its facility.
Advanced Custom Geothermal was founded in 2007, combining two companies – Walsdorf Heating and Cooling LLC and Steffes’ company, Advanced Custom Air LLC. Walsdorf’s introduction to geothermal came four years earlier when he installed his first system in his father’s house.
Today, the WaterFurnace dealer says at least 75 percent of his business is the installation of geothermal systems. But before he recommended geothermal to the Blums, he first suggested they employ another local firm to conduct an energy audit of thehouse, which would show the home’s heat loss and generate suggestions for improving its energy efficiency.
“We would sooner not put in geothermal and lose a sale if homeowners would agree to the audit and make their home tighter,” said Walsdorf. “You have to do it systematically, and that means making a home more energy responsible with insulation, better windows, etc. before considering the heating system. The more upgrades a homeowner makes, the greater impact it will have on the heating and cooling system we design for them, often resulting in a smaller system.”
A geothermal system takes advantage of free solar energy stored just below the surface of the earth. Using a series of pipes (an earth loop) buried in the ground and a geothermal or ground source heat pump, the geothermal heating and cooling system extracts heat from the earth and carries it to a home in the winter. An indoor unit compresses the heat to a higher temperature and distributes it throughout the home.
In the summer, the process reverses and the system extracts heat from the home and rejects it to the earth. In both cases, the geothermal system delivers consistent temperatures and efficiencies that exceed those of conventional home comfort systems, offering homeowners savings as high as 70 percent on heating, cooling and hot water.
In addition to consistent temperatures, a geothermal system ensures good indoor air quality (IAQ). That’s because the system does not require combustion and therefore produces none of the products associated with combustion, including carbon monoxide, which can be dangerous if not vented properly. And, the average geothermal system lifespan exceeds 24 years – compared to 15 years for a more traditional heating and cooling system.
Based on the results of the energy audit and what he already knew about the property, Walsdorf was confident that a geothermal system would provide the efficiency, comfort and sustainability the Blums sought. In fact, he predicted that the heating and cooling expenses for the house would shrink from the current level of $5,390 per year to just $1,963 per year by installing a geothermal system designed around the WaterFurnace 7 Series variable capacity geothermal heat pump.
The geothermal system at the Blum house uses eight 300-foot trenches, with 600 feet of pipe in each trench. “That may sound like a lot, but if we had used a single slinky loop in a smaller land area, we would most likely have needed 9,600 feet of pipe, or almost twice the amount of pipe we actually used,” explained Walsdorf. “In this case we had plenty of land to work with, so we were not confined to a single horizontal loop or a drilled vertical loop, which can be much more costly.”
Selecting the right piece of WaterFurnace equipment was easy for Walsdorf, who said that the 7 Series unit was a perfect choice, providing the design flexibility he needed to meet the Blums’ requirements. “The Blums wanted five zones, and prior to the introduction of the 7 Series, there was no geothermal unit capable of meeting that requirement,” he said. “Up until now, the most I could provide with a two-stage unit was four zones, and the smallest of those zones had to handle 40 percent of the total system output.
“But, the 7 Series variable capacity unit allows us to have more zones than conventional two-stage equipment – up to six – and allows us to design smaller zones. So, now we can make a 150- or 200-square-foot bedroom its own zone without worrying about too much air entering the space.”
The variable capacity feature on the unit allows it to scale output to exactly the level needed rather than the “high” or “low” speeds found in normal systems. The unit can ramp down to 20 percent of normal operation for ultra-efficient conditioning or up to 130 percent output using SuperBoost™, for periods when extra cooling is needed.
The 7 Series is the only unit to surpass both a 41 energy efficiency ratio (EER) and a 5.3 coefficient of performance (COP). This represents efficiencies twice that of traditional air conditioners or heat pumps and 30 percent greater than current geothermal units. In addition to energy savings, the Blums were able to take advantage of a federal tax credit that amounts to 30 percent of the installed price of the system.
“In addition, we don’t have to listen to a noisy unit on the outside or even see it, which means the geothermal system will help preserve the look of the old home. And it’s green, which is another benefit that is important to Cathy and me. We’re relying on the earth to heat and cool our home rather than other fossil fuels.”
According to the Blums, the geothermal system is contributing to a beautiful home that is as efficient as it is charming. Just as importantly, it has introduced them to a contractor who they now consider a friend.