Geothermal Design ‌• Trust the Numbers

CM Services' Geothermal Design is specifically configured for the climate and geology of Western Pennsylvania (or your location) and typically saves 50% on electricity cost over the traditional air source heat pump over a 30 year period. Our Geothermal Design includes vertical loop-field design, flow center, piping schematics and material specifications.

To properly design and size an HVAC system, a building specific calculation must be performed to determine the maximum heating and cooling loads. This critical step is nearly always overlooked and typically results in the installation of an over-sized HVAC system. Once an appropriately sized furnace is selected, we use the LoopLink™ computer program to calculate the Life Cycle Cost of various HVAC Systems utilizing fuels available at the site.

Scope of Services consists of three engineering studies and reports as well as the recommendation of testing and monitoring hardware and software.

Heating and Cooling Loads Calculation

Heating and Cooling Loads Calculation: This first step calculates how the building interacts with its environment based on its construction, location, orientation, equipment and occupancy and determines how much heating and cooling the building needs on the coldest and hottest days of the year. Commonly referred to as an ASHRAE Manual J Calculation, this first and most important step in the HVAC design process, and is also the step most often overlooked.

Data for the loads calculation is most often gathered by means of a site visit when the building is measured to determine its physical characteristics, and the client interviewed to determine its occupancy requirements. The existing HVAC equipment is evaluated to determine if retrofitting with geothermal is a viable option. Should accurate CAD design drawings exist of the building and its HVAC System, the site visit may not be necessary.

Geothermal Borefield Design

Geothermal Borefield Design: Once appropriate equipment is selected for the building based on its heating and cooling loads, The GSHP Design software calculates the depth of the borehole based on geology, bore diameter, grout thermal conductivity, and configuration of the borefield design corresponding to the equipment selected for the building. Two options (one u-tube and double u-tube) are provided affording the building owner additional flexibility and savings when contracting with the Geothermal Drilling Contractor.

Traditionally, geothermal installers use the standard rule-of-thumb that was established over 30 years ago that 1 Ton of GeoThermal heating/cooling = 1 borehole 175' deep. Our In-Situ Borehole Thermal Response Tests (TRT) indicate that a well designed borehole in Western Pennsylvania's geology can yield far greater heat transfer rates than the standard, reducing the amount of drilling required by as much as 50%.

Ground Source Heat Pump

Ground Source Heat Pump (GSHP) Design: Is performed in accordance with the International Ground Source Heat Pump Association design manual and appropriately sizes the HVAC equipment based on the heating & cooling loads and availability of back-up heating sources. We are able to provide a water-to-water (required for hydronic heating systems) or a water-to-air design option (traditional heat pump or split HVAC furnaces). Specific equipment from multiple manufacturers are recommended providing options to building owners and their HVAC contractors.

The GSHP Design report compares the 30-Year Life-Cycle heating and cooling costs for the Geothermal system versus traditional systems operating on available fuels (oil, propane, natural gas and electricity). Typical savings for a 3000 S.F. house over 30 years is in excess of $30,000 compared to a conventional air-to-air heat pump.

Our designs also include recommendations for a web-based Geothermal monitoring system that allows the building owner to monitor the maintenance and performance of their GeoThermal heating and cooling system both at the building and remotely on a mobile device.

GeoThermal Hydronic (GSHP) Prototypical HVAC Systems


#6 Blackburn FarmHouse

A Concept Design of a "Renovated" Western Pennsylvania Farmhouse with a 21st Century, One-Floor Living Module aspiring to the Living Building Challenge.  

Multi Level Single Family residence w/ 7,000 sf (conditioned space) built in 2015. The HVAC system, a 4-Ton Water-to-Water Ground Source Heat Pump, 50 gal Surge Tank, servicing an Air Handler and 2 In-Floor Hydronic (heat only) zones.

The ground loop consists of 1 - 200' deep borehole with double 3/4" loops monitored by GES  which includes actual system flow rate, loop temperature, tank temperature and power consumption.

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Otis' Barn

A Traditional Western Pennsylvania Timber Frame Bank Barn w/ Concrete Basement, 60' x 40'. 

A 5,400 sq. ft. Timber Frame Bank Barn w/ Double-Dutch Gambrel Roof an Hay Lofts, built in 2010. The HVAC system, a 2-Ton Water-to-Water Ground Source Heat Pump, 35 gal Surge Tank, servicing an Air handler and 2 In-Floor Hydronic (heat only) zones.

The ground loop consists of 1 - 200' deep borehole with double 3/4" loops monitored by GES  which includes estimated system flow rate, loop temperature, tank temperature and power consumption.

Dave - DIY Install

The Home, a Split Level Single Family residence w/ 2,500 sf of conditioned floor space was built in the 1970s. The 3-Ton Electric Heat Pump had lost its Freon charge with only the Emergency (back-up) Strip Heater providing heat to the house.

A Licensed Electrician, Dave choose to Retrofit his existing Electric Heat Pump with a 4-Ton Water-to-Water GSHP controlled by the GeoT 1 Controller. The 50 gal Surge Tank stores Hot and Cold Water to the Air Handler providing Forced-Air Heat and Air Conditioning to the home.

He decided to go with the Hydronic Contractor & DIY Package which includes Construction Plans, Specs & M&E Estimate and replaced his old air handler with a new efficient model containing a Water “A” Coil. A 200’ deep x 6” dia. Borehole (Water Well) was drilled and the double 3/4” loops installed IAW our Closed-Loop Vertical Borehole Design and Installation Procedure.

Dave did his install for $6,600 and says if he didn’t replace the Air Handler he would have come in around $5,000

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GeoThermal HVAC Design

Includes: Floor Plans, Elevations, ASHRAE manual J Heating/ Cooling Load Calc , Manual D Ductwork Design, Equip Selection (w/ Options), Closed-Loop Borehole Design, Hydronic system design including Equipment, material quantities and specifications.


Home’s up to 3,000 SF

Larger Additions +$1/SF

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Geothermal HVAC System Evaluation

Have an Existing Geothermal System and want to Explore the Hydronic GeoT Retrofit? Send Us an Inquiry and Describe your System including Pics of your Equipment and your Furnaces's Data Tag.


Site Visit Evaluation Report w/ Options/Costs



GeoT 1 Controller - 1 Zone

  • Control and Regulate Surge Tank Water Temp

  • Monitor In/Out loop Temperatures

  • Control 1 Hydronic Zone via Cycle Timers

  • Manual On for Circulators is Standard.

  • Room Thermostats & Temp Sensors by Others



GeoT 3 Controller - 3 Zone

  • Control and Regulate Surge Tank Water Temp

  • Monitor In/Out loop Temperatures

  • Control 3 Hydronic Zones via Cycle Timers

  • Manual On for Circulators is Standard.

  • Room Thermostats & Temp Sensors by Others