Case Study · Geothermal · Evanston
A century-old Evanston home goes geothermal.
How Ken & Lauren moved a 110-year-old home fully off fossil fuels using ClimateMaster Trilogy geothermal—quietly, efficiently, and without compromise.
ClimateMaster Trilogy 45
9 vertical boreholes
5.1 COP heating
Q-Mode hot water
The solution
Ground-source geothermal: the highest-efficiency option available.
We designed a ground-source geothermal system built around the ClimateMaster Trilogy 45 Q-Mode—one of the most efficient geothermal heat pumps available—paired with a closed-loop vertical bore field engineered for the property's lot constraints.
Heat pump
ClimateMaster Trilogy 45 Q-Mode
Ground loop
9 Vertical Boreholes
Variable-speed, two-stage geothermal heat pump with integrated hot water generation (Q-Mode). Achieves up to 45 EER in cooling and 5.1 COP in heating—among the highest efficiencies in the industry.
Closed-loop vertical bore field drilled to depth on the property. Vertical bores are ideal for older urban lots where horizontal trenching isn't feasible. The earth provides a consistent 50–55°F heat source year-round—independent of weather.
The challenge
110-year-old home.
Ambitious goals.
Urban lot constraints.
Ken and Lauren's home is a beautifully maintained 110-year-old residence in Evanston—the kind of place where character and craftsmanship define every room. But like most century-old homes on the North Shore, it came with aging, inefficient gas heating equipment and no viable path to modern ductwork.
The homeowners wanted to move entirely off fossil fuels for space conditioning while preserving the home's historic character. Conventional air-source heat pumps were considered, but the home's heating load and the owners' desire for maximum efficiency and longevity pointed toward a different solution entirely.
Why geothermal for this home
Stable earth temperatures. Maximum efficiency. No weather dependence.
Ground-source heat pumps exchange heat with the earth rather than outdoor air. Because ground temperatures remain stable year-round (around 52°F in northern Illinois), geothermal systems don't lose capacity in extreme cold the way air-source units can. For a 110-year-old home with a substantial heating load, this makes a measurable difference in both comfort and operating cost.
The Trilogy 45's Q-Mode also generates domestic hot water as a byproduct of the cooling cycle — essentially free hot water in summer and highly efficient hot water year-round, further reducing the home's total energy footprint.
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Up to 5.1 COP heating / 45 EER cooling
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Full heating capacity at any outdoor temperature
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Integrated hot water generation via Q-Mode
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No outdoor unit — zero noise, zero visual impact
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Eliminates all on-site fossil fuel combustion
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25+ year equipment life / 50+ year loop life
The process
Site assessment to final commissioning—a thoroughly documented installation.
Step 1: Site assessment & load calculation
Step 2: Bore field drilling
Comprehensive Manual J analysis of the home's thermal envelope. Assessed lot geometry and soil conditions for bore field design. Identified insulation opportunities to right-size the system before committing to loop field depth and count.
Nine vertical boreholes drilled on-site and fitted with closed-loop HDPE piping. The bore field was grouted, pressure-tested, and connected to the mechanical room via header piping—all completed with minimal disruption to the yard and landscaping.
Step 3: System installation
Step 4: Commissioning & verification
Installed the ClimateMaster Trilogy 45 indoor unit, connected to the existing air distribution system, and integrated the Q-Mode for hot water pre-heating alongside the existing water heater.
System commissioned with verified loop flow rates, entering and leaving water temperatures, and airside performance data. Every zone tested for comfort delivery before final sign-off and homeowner handoff documentation.
The results
100%
5.1
50+ year
Electrified—no gas remaining
COP heating efficiency
Designed loop field lifespan
Ken and Lauren's home is now fully geothermal — heating, cooling, and domestic hot water generated by the stable temperatures beneath their yard. No outdoor compressor noise, no combustion byproducts, no weather-dependent performance drops.
A high-efficiency system with quiet operation, long equipment life, and no outdoor compressor. For the right house and lot, geothermal can be the cleanest long-term path.
Geothermal is not the first recommendation for every home. It makes the most sense when the heating load, lot conditions, drilling access, budget, and long-term ownership plan all line up.
“Boris and his team did a fantastic job replacing our gas furnace and air conditioner with a new geothermal heating and cooling system.
I highly recommend them.” — Ken Itle