May 1998

Copper DX Geothermal Heat Pump Web Site

Copper Applications in Health & Environment

By Dave Kaaret

The Copper Development Association is sponsoring the creation of a web site designed to allow homeowners to compare the economics of heating and cooling their homes with copper direct exchange(DX) heat pump systems rather than using conventional heating and cooling systems. The heart of the site will be a cost analysis program into which users will specify details about their existing, or prospective new, homes. Users will receive an estimate on the installation and heating and cooling costs of a copper DX system vs. the costs of using oil, gas, electric or a conventional air-to-air heat pump.

The site will also contain an overview of DX systems: how they work, when they are most likely to be economical, how they are different from air-to-air and traditional geothermal (ground source) heat pumps.

Goals of the Site

The oil, gas, and electric heating and cooling systems used in most homes today unnecessarily waste money and energy and generate large quantities of greenhouse gases. If instead, homes were heated and cooled with energy efficient direct exchange (DX) geothermal heat pumps, homeowners would save money, the United States would save energy, and the world would reduce its greenhouse gas emissions.

The Copper DX Geothermal Heat Pump Site is meant to make homeowners aware of the benefits of DX systems and provide them with a tool to let them calculate the costs savings that they can realize.

History of the Site

The site is an outgrowth of a CDA sponsored research project conducted by Prof. W. Stanley Johnson of the University of Tennessee at Knoxville (an overview of this project can be found in the February 1998 Innovations article CDA Backs DX Geothermal Heat Pump R&D). Users specify where they live, if it is a new home or a retrofit, square feet, number of windows, amount of insulation, if the home air conditioned, etc. and the program calculates the number of BTUs needed to heat and cool the home. It then calculates the cost of installing and using copper DX and other heating and cooling systems and provides the life cycle cost of each type of system based on a user entered discount rate for future energy costs. If the economics of a DX system appear to be favorable the user is directed to a list of DX contractors for follow-up consultations.

A DX copper heatpump system may offer significant saving for you. For further information please contact the following sources.

- It is assumed that Oil and Gas systems use electric air conditioning
- Heating and Cooling Costs (in $)
- Example of Analysis from Beta Copper DX Web Site

Level of Analysis

Because the audience of the site is homeowners, and not DX professionals, the number and type of questions that it is feasible to ask are comparatively limited. For example, the average homeowner cannot be expected to answer questions about soil conditions or the ductwork in a home. Also, if the program asks too many questions users will be overwhelmed and not answer them.

In addition, because the site covers the entire US, it is difficult to provide costs that are accurate over the entire country. The cost of installing and using DX and other heating/cooling systems varies depending on soil conditions, weather, local labor costs, etc. While the system does have some ability to handle these items, the size and diversity of the US limits the accuracy possible in a program of this type.

As a result, the program provides a "first cut" analysis of the cost of using and installing the different systems. The site depends on follow-up analysis being conducted by DX contractors.

Overview of economics of DX vs. Conventional Heating & Cooling Systems

  • The inside the home cost of installing a DX system is comparable to that of conventional systems, around $2,000 per ton, with a one ton system being able to heat or cool 12,000 BTUs.
  • DX systems, unlike oil and gas heating, do not require the addition of a second, electric air conditioning system.
  • Air-to-air heat pump systems often require a second heating and cooling system because they cannot handle temperature extremes. DX systems work best in extreme temperatures.
  • On the negative side, DX systems require copper tubing to be buried in the homeowner's yard increasing installation costs.
  • Once a DX system has been installed it is usually far cheaper to use than conventional systems.

Status of the Site

A fully functional beta version of the site has been completed. DX contractors and Professor Johnson are testing the results of the cost analysis program. Their testing has turned up a number of issues, especially as regards installation costs. Once these issues have been resolved the site will receive a graphical makeover and go online. The site should be up in the fall of 1998.


Andrew G. Kireta Jr.
National Program Manager
P.O. Box 940
Franklin, IN 46131
Tel: 317-346-6442

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