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Geothermal Changing The HVAC Landscape

<![CDATA[In a ground-source geothermal system, all of the chiller/heat-pump equipment is located inside, which adds to overall system reliability and longevity.]]>

As interest in geothermal technology grows, educational efforts are helping architects confidently specify these environmentally friendly systems.

By Jay Egg, Egg Geothermal

The St. Patrick’s Cathedral project, in downtown Manhattan, is an example of how geothermal systems can be installed essentially anywhere as permanent infrastructure and have low overall impact on the site. Image: PW Grosser

Most would agree that green/sustainable building design and construction has become the norm, whether it’s a new or a renovation project. That does not mean that the quest has ended for improved energy efficiency, better indoor air quality and, most important, reduced environmental impact. Ground-source heat pump geothermal technology is at the forefront of this unending effort because it can deliver efficient heating and cooling with minimal environmental impact and be effective virtually anywhere in the country. The market for these systems is expected to grow about 12% annually through 2021 and the technology continues to receive governmental and utility support.

The geothermal HVAC industry enjoyed a period of federal tax-credit support between 2009 and the end of 2016. The tax credits were not renewed at the beginning of 2017, but the new Brady Bill, currently in the U.S. House of Representatives, includes language that rekindles a 30% federal tax credit for geothermal HVAC systems, retroactive to January 2017. While this is not yet law, it has a reasonably good chance of making it into the federal budget.

At the local level, many states and communities have instituted their own geothermal codes, rebates, or other types of financial incentives. The website for the Database of State Incentives for Renewables & Efficiency (DSIRE, is the best tool for determining what credits are available.

New York State is a good example of forward thinking that is making a difference in geothermal implementation. The New York State Energy Research and Development Authority (NYSERDA,, Albany, working with other governmental agencies, has established a robust geothermal incentive program that includes significant quality assurance and control guidelines. The program is based on regulations and training established by the International Ground Source Heat Pump Association (IGSHPA,, Stillwater, OK. This provides a level of quality control that was not attainable by reliance on federal tax credits.

In a ground-source geothermal system, all of the chiller/heat-pump equipment is located inside, which adds to overall system reliability and longevity.

Overall growth

The greatest growth in the geothermal industry has been realized in larger governmental and private-sector installations for commercial and mixed-use communities. On the West Coast, Internet giant Google will install a geothermal system to service the three office buildings that make up their Bay View Campus facilities in San Francisco. The heat pumps are expected to provide 95% of the needed cooling. Cooling towers will provide the remaining 5%, primarily on the hottest days. In that area of the country, the savings isn’t natural gas. It’s precious potable water and 8 million gal. saved in a year is significant.

There is also notable growth in the multiple-residence market, specifically using a system to serve multiple single-family homes. In New York, National Grid USA Service Co. Inc., Waltham, MA, the nation’s largest privately owned utility, has installed a multiple-home geothermal demonstration project at Glenwood Village, Riverhead, NY. The loop field will be installed in a common recreation area and connected to 10 homes. Initial expectation is that homeowners in those experimental residences will experience a 25% reduction in HVAC costs.

In Ontario, Enbridge Gas, Toronto, is installing geothermal systems for several homes. The common thread in this effort is that they are installing geothermal loops in places where the company would normally install natural gas lines.

There have also been some remarkable smaller companies popping up. One of those is Dandelion Energy, Saratoga Springs, NY. The 2017 startup aims to help homeowners replace their truck-delivered-fuel heating systems with affordable geothermal systems that provide heating, cooling, and hot water. Growth in the industry is also robust in retrofit markets, simply because of the considerable costs that can be incurred to replace chillers, heat pumps, and air-distribution equipment in those projects.

The heart of a geothermal system is the circulators, or fluid pumps. These circulate the water through the pipes that transfer heat to and from the exchanger field, delivering Earth energy to equipment inside the building.

Still Misunderstood

Yet, geothermal is often misunderstood. A good example is the Empire State Plaza in Albany, NY. Engineers stated that installing a geothermal system would not be possible, primarily because they thought the only approach was to drill holes for geothermal loops. In fact, the project can likely be completed using the existing cooling water from the Hudson River as a heat source/sink for the chillers and heat pumps.

Geothermal systems are easiest to implement in new-construction projects because the exchangers can be placed under buildings and/or parking lots, installed in structural piles, or placed in adjacent bodies of water. However, the technology is adaptable to nearly every conceivable application. Consider this from Richard A. Sileo, senior engineer with Landmark Facilities Group, the facilities manager for St Patrick’s Cathedral in Manhattan: “At the outset, we evaluated a conventional HVAC system, but determined it would pose too many challenges for this historic building. We conducted a feasibility study and found that a geothermal system let us meet our goals with the smallest impact.”

NYSERDA has recognized the need to educate professional architects and engineers and is offering AIA- and PDH-accredited courses in New York. These events are scheduled at high-profile facilities throughout the state.

NYSERDA is providing the CEUs for architects, engineers, and other professionals throughout New York in an effort to educate specifiers about the far-reaching benefits of geothermal HVAC technologies.


Geothermal designs are considered to be an infrastructure-level investment because the exchanger installed in the earth or an adjacent body of water will last for generations. The pumps, heat pumps, and controls that drive the system may need periodic replacement due to wear and tear, though properly specified and installed equipment will last between 20 and 50 years. But the geothermal exchanger (in-ground portion) is as permanent as the slab and structural pilings of the buildings themselves.

While large exchange installations are extremely durable, smaller systems designed for a small business or a home have not always measured up. Educational efforts for architects, engineers, and other design professionals have considerably reduced this concern. As with many engineered systems, retaining a professional with some experience, getting a couple of estimates, and having a consultant review the design are very small investments that will ensure proper design and installation.

IGSHPA has been working with the International Association of Plumbing and Mechanical Officials (IAPMO, Ontario, CA) to write codes for buildings that will integrate the specifications into local building codes in the U.S. and internationally. IGSHPA has put their training materials online to further education.

In an effort to help professionals understand what is going on in the market, Commercial Architecture and IGSHPA are collaborating to provide extended coverage of geothermal technology and the market. We plan to bring you information on the Cornell Campus project, recently completed on Roosevelt Island in New York. This geothermal facility will demonstrate the versatility of geothermal HVAC systems. Also, we will show just how far and wide geothermal systems are implemented as we go to Texas and share information on hundreds of schools that are now geothermal heated and cooled. Also in Texas, we’ll share an overview of The Whisper Valley development, a mixed-use, 100% geothermal installation with utility-grade geothermal infrastructure. Then we will go to Google’s new facility near San Francisco, where they are implementing geothermal exchange in the building structural piles. Finally, we will travel to Atlanta to explore the 100% geothermal Pinewood Forest mixed-use community. You’ll find all of our coverage at

Jay Egg, president and founder of Egg Geothermal, Kissimmee, FL, is a consultant and designer of geothermal HVAC systems. He has authored two books and numerous articles on the subject. He can be reached at

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