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Frequently Asked Questions

Over the years, interest in the EarthLinked geothermal heat pumps has generated many questions. This list is not completely inclusive, but it will attempt to point out the most common questions. Please visit for more FAQ's, or contact us here at Pink's DX Technologies, LLC. 

What sets EarthLinked Technologies, Inc. (ETI) apart from air source heat pumps?

By using the constant, favorable temperature of the earth as its heat source, ETI heat pumps harvest the renewable solar energy stored in the earth. Mechanical simplicity and the constant earth temperature assure longer equipment life, less maintenance, and much higher efficiencies than air source heat pumps.

What sets ETI apart from other geothermal systems?

Because the ETI direct method does not consume energy to circulate water; does not have an intermediate heat exchanger from water to the refrigerant; exchanges heat through copper refrigerant tubing; and it uses proprietary ETI refrigerant flow controls, it has proven to be 15%-25% more efficient than water-based geothermal heat pumps.

How is the earth loop system installed?

Direct Axxess earth loops can be installed horizontally in pits or trenches. They can also be installed vertically or diagonally using small boring equipment. A 3" x 100' borehole is all that is needed, and the surface footprint is very small (typically 7'-14' diameter of disturbance).

What special training and equipment is required for installation?

Typical HVAC installation equipment, and knowledge of copper brazing methods are used in installation. There's no need for an expensive purge cart, fusing tools, IGSHPA training, loop circulation pumps, antifreeze, or pump sizing knowledge required because of water loops. On the refrigerant side, the factory-assembled earth loops are brazed to pre-fabricated manifolds. Visual indicators assist in proper system charging--no charging charts needed. Little special training is required for installation. 

 How Long have ETI systems been operating?

In 1980, EarthLinked Technologies, Inc. began research and development of ETI systems. In 1985, field demonstrations began for ten electric utilities from Florida to Michigan. Marketing commenced in 1995. ETI units have now been over 100,000,000 hours in service.

Is it difficult to install the EarthLinked system in an existing home?

Not at all! Existing duct and air handlers can be used with minor modifications if they are in good condition and are appropriately sized. The Direct Axxess loops require a small surface footprint and can fit in most any yard.

How long will the earth loops work?

Copper is one of the few metals that exists naturally as an element in the earth. A noble metal, it is essentially immune to corrosion in most underground environments because of the protective film that forms naturally on its surface.

In rare exceptions, where pH readings exceed safe levels, cathodic protection for the in-ground copper is available from ETI. With some installations dating back to 1980, ETI has never experienced a field failure of the copper pipe due to corrosion.

Visit the Copper.Org website for more information, and read this article about copper tubing in soils.

How does an EarthLinked geothermal heat pump work?

The standard refrigerant compressor circulates refrigerant through the earth loops (with sufficient velocity to transport the compressor oil through the system) while heating or cooling. The proprietary ETI refrigerant controls assure 100% usage of both the evaporator and condenser. This allows optimum efficiency at all times, and ensures no sub-cooling nor super-heating of the refrigerant.

In the heating mode, the compressor sends liquid refrigerant to the earth (evaporator). There, it experiences a latent heat exchange by boiling/evaporating into a low pressure gas. The compressor then pressurizes this gas, concentrating the heat extracted from the earth. The high pressure gas goes to the condenser (refrigerant air coil or hydronic water coil) and heats the air or water.

The process is reversed in the cooling mode as the earth becomes the condenser, and the air coil or hydronic heat exchanger becomes the evaporator.

Where is the compressor unit installed?

Because the EarthLinked system does not require an outdoor fan and coil, the compressor unit can be located in a basement, utility room, attic, garage, crawl space, or outdoors. A fully enclosed, well insulated (foam) cabinet assures quiet operation.

Can the system heat water?

Yes! In fact, from one single unit, one could heat and cool air and heat domestic water; or one could heat and chill water and heat domestic water; or one could heat and cool air and heat hydronic water. the domestic water heating aspect is set up as priority. When the domestic water needs to be heated, the unit stops what it's doing and specifically runs to heat the domestic water.

Commercial water heating is also an option. Applications such as hotels, restaurants, dormitories, apartments, nursing homes, schools, swimming pools, laundries, and many more could save up to 75% on their water heating costs.

Can I install my own system?

In short, no. EarthLinked Technologies, Inc. has authorized dealers that have been trained specifically for the installation of their products. Knowledge of refrigeration and HVAC systems is required, along with a refrigerant handling license. The EarthLinked system is only available through factory authorized dealers. Visit here to locate an authorized dealer near you.