Pandemic Project Extraordinaire – Installing a Home Geothermal Heat Pump
Imagine: Eliminating Natural Gas Use for Heating (and Reducing Energy and Water Use at the Same Time)
By Clark Bisel, CIPL supporter and St. Stephen’s Church member, Moraga, CA
What better time to do a big project than during a pandemic, when you are not supposed to leave home, and no one is going to come over any see your mess anyway? Converting our home heating/cooling to geothermal was an idea I had had for several years, so to stave off cabin fever while stuck at home I decided it was the perfect time to tackle this project.
Geothermal heating/cooling is relatively simple and foolproof, using the thermal mass of the ground to heat/cool your house. The ground, after you go down from the surface a few feet, is a relatively stable temperature year-round. The concept is similar to having photovoltaic panels on your roof that directly produce electricity from sunlight, but in this case the sun indirectly moderates the ground temperature. A geothermal heat pump recirculates water deep underground and carries it up to a system (in our case located in our attic) that transfers the relative heat or coolness of the water to produce warm or cool air, which is then distributed through our regular ventilation system, depending on the home’s heating or cooling needs.
There are two main parts to the system:
- Geothermal Bores – Needing to couple the ground with a building’s thermal needs, three vertical pipes were installed in the ground. These vertical borings, around 6” in diameter, were chosen over a horizontal piping loop which takes more land area, which was not available. Three pipe risers (each having one water supply and one water return) extend into the ground 350 feet. The vertical pipes are connected together and water is circulated within them and then to a geothermal heat pump in the house, transferring ground heat (or relative coolness) to the house.
- Geothermal Heat Pump – A geothermal heat pump is used in lieu of a natural gas furnace. Our furnace was nearing the end of its life, so something would need to be done in any case. This new heat pump is also multi-speed, offering output more efficiently matched to building thermal needs. The heat pump provides both heating and cooling to meet the house’s needs –
- Heating – The heat pump converts the heat from the water that has circulated in the ground (coming back to the unit about 70F) into warm air (at a bit more than 100F). This warm air is pumped into housing duct work by a fan, exactly similar to your furnace system. But the key difference is that NO natural gas is used to heat the air, only heat extracted from the ground and the heat pump operation.
- Cooling – The heat pump generates cooling much like a traditional AC system, but in lieu of an air-cooled condenser (typically located outside the house where its noisy operation is over-looked) it uses the ground for its condensing needs. This use of the ground makes the air-conditioning process much more energy efficient – using a mild, relatively constant ground temperature as opposed to a very warm and wildly fluctuating air temperature, such as on a 105-degree day.
So, this sounds rather simple. But it’s not that simple and you rarely see these installations on the West Coast (with a few notable exceptions). The execution is not for the faint of heart and most code officials need convincing that you know what you are doing as they are generally unfamiliar with this idea.
CHALLENGES ALONG THE WAY
- Finding an installer for the new heat pump who knows exactly what they are doing, minimizes time in your house (virus exposure), and knows every step of the process.
- Picture having a large military tank parked on your front yard, steel treads and all: The drilling rig that bores the holes into the ground for the geothermal piping is a truly formidable beast. The drilling rig also is accompanied by an armada of supporting equipment that creates a cacophony of diesel engines running constantly. Our driveway was taken over by a large storage tank for muddy water, used in the drilling process. Lasting weeks, our neighbors were initially quizzical, wondering if we had struck oil. They were excited to hear about the project, though, and very understanding (although I’m sure they were glad to see the rig go).
The only good thing was taking a rather idyllic-looking photo of the rig with fall leaves changing color – perfect for one’s holiday card.
But think of having this armada visit you twice – which is what needed to happen because one of the vertical piping pairs unfortunately had a leak and an entirely new riser set had to be installed. The entire drilling contingent had to return to the front yard again, but the COVID surge also shut down driller operations, so the project had a temporary hiatus, returning to complete the job in February.
Crawling under the house or in the attic – one has to connect the geothermal bores outside with the new heat pump inside, and to save cost I did a lot of this myself. During a pandemic you don’t want outsiders in your house for an extended period of time and this jig-saw puzzle takes time and perseverance to pull new main piping in a tortuous path to where the heat pump is located. To double the fun, a new (high capacity) electrical feeder is also needed for the heat pump’s operation – so in my case this meant significantly more time in the attic.
New front landscaping: After having a drilling rig on the front yard and then connecting the vertical borings with 4’ deep horizontal trenches reminiscent of a WW1 battlefield, the lawn was now a mud field and a new yard was mandatory. When it rained the trenches filled with water and the yard was an unbelievable quagmire of oozing, slick clay. We took the opportunity to eliminate grass and reduce water use in the new landscaping plan (this is the water part), and we couldn’t be happier with the result.
Imagine being done with the project and using no natural gas for heating; a much more efficient cooling system; a new and very attractive front yard that has reduced water usage without a lawn; a solution that adds value to the house, is a wonderful cocktail story, and will be running strong many decades to come.
Imagine looking at this every day…
I can imagine all of this, but I am glad this project is (almost) over too!
Everything works great, by the way and exceeds my expectations. If you are considering this project, it qualifies for the lucrative solar tax credit, but do it soon in order to take advantage of the credit before it expires.
About the author
Clark Bisel – has more than 30 years of prior experience with a leading international mechanical, electrical, plumbing engineering firm. He now heads his own firm which counsels owners and design teams on new strategies for the built environment.
Mr. Bisel’s completed design projects exceed 45 million square feet of space in various building types and systems. These encompass commercial developments, significant historic buildings, campus environments, central utility/co-generation plants, communication systems, energy efficient systems, sustainable facilities, phased design, and feasibility studies. Clark has historically been very active in international projects.
He is recognized as an industry leader in sustainable design. His projects have been recognized by their uniqueness in approach and for their energy performance results. These projects have promoted their inter-disciplinary nature required to result in environmental efficiency gains. He is a design advisor to several architects and developers to promote new, strategic thinking regarding energy performance in buildings.
Significant factors related to sustainable design:
- He was involved during the formation of the United States Green Building Council and his previous firm is one of the original founding members.
- He has been a committee member to establish LEED criteria for Core and Shell projects.
- He has numerous projects at Platinum, Gold, and Silver LEED certification levels.
- Several projects have received AIA Committee on the Environment Top 10 recognition.
- He has completed Zero Net Energy projects (ZNE), including one of the largest projects in the United States (net zero ready).
Addendum – additional notes from the author for those considering a geothermal heat pump
If you think your home, congregation, or business might be a good candidate for a geothermal heat pump, feel free to contact me at firstname.lastname@example.org . I am not a contractor, but I may be able to help you assess whether this type of system could make sense for your site and circumstances. A few pointers/disclaimers:
- There is no single contractor (based on my experience) that you can call who will take care of all project aspects. One has to be willing to do much of the work coordinate many of the entities.
- The landscaping portion of this undertaking should not be taken lightly – when the drilling rig enters your property it will obliterate anything it touches. The landscaping portion for us was one of the most expensive aspects of the whole project and the scope of this likely has a very high variability.
- I am apprehensive about reporting financial values, due to the widely varying factors involved. A project such as this has a high capital requirement and a long payback, with one needing to account for every factor involved. (For example, in my case there was an aging natural gas furnace that needed replacement in the short term, so that was valued in my economic analysis.)
- The geothermal unit reports a lot of performance detail over the home Wi-Fi network, so a lot of detail is reported instantly. This is what led me to the conclusion that the system is performing much better than expected – I had actual performance data immediately. (The analogy is when you take your car in for service, the mechanic plugs into the car’s diagnostic port and gets a wealth of detailed information)
- The Federal tax credit was a real driver for me and is slated to be phased out. Houses of worship, schools, religious institutions (non-taxable entities) cannot take advantage of this – their members, however, can.
- I have no general ‘how to’ assessment of the project because scope parameters for each situation vary so much.
- I do have a suggestion for an alternative system in lieu of a full geothermal system – one that is easier to implement, having a contractor handling the entire scope, getting rid of natural gas, and not requiring one to replace entire landscape, etc. It not quite as efficient, but still very good. It’s an air-to-air heat pump and, in much of California, is a good option.
Congregational Highlight: First AME, L.A., a Champion of Climate Justice
First American Methodist Episcopal Church in Los Angles, was founded in 1872 by Bridget (Biddy) Mason, a formerly enslaved woman. After moving to California and, with the help of local black and white abolitionists, she successfully sued in court to win her freedom. Support for civil rights, social movements, and empowerment of and ministry to local communities are the bedrock of this beloved church. And for the last 16 years, First AME has been an example of Creation protection.
Rev. Leonard B. Jackson guided the church – one of CIPL’s earliest members – on an energy efficiency journey in the early 2000’s. The church underwent an energy audit, installed compact fluorescent light bulbs and lighting sensors, and upgraded to low-flow toilets. Rev. Jackson demonstrated First AME’s support for strong and just climate policy – he is one of 165 Christian, Jewish, and Muslim leaders that signed a 2006 letter to California’s Governor and Legislature urging leadership on global warming.
Today, action on Creation-friendly efforts continues with Pastor J. Edgar Boyd. The church took advantage of the Los Angeles Department of Water & Power‘s Direct Install Program, which provided an energy and water audit, energy-efficient lighting, and water-saving measures. But what has made a real difference in energy reduction is Pastor Boyd’s decision to have an analysis of the church facilities’ Demand Charges done.
Go Solar America, an energy management company that has worked with other congregations in L.A. County, performed a free walk-through and audit of First AME’s facilities’ energy use. By installing devices on some of the biggest-use appliances and educating staff on timing and demand, the church is saving thousands of dollars each month.
Pastor Boyd calls the assistance of CIPL and Go Solar America a “Godsend” in facilitating energy savings and money. The money saved goes to operations and the multiple ministries that First AME supports. “The church is front and center in maintaining a good environment,” states Pastor Boyd. “We are commanded, from the Garden of Eden, that our first priority is to take care of our Garden. Taking responsibility for the environment is a blessing and a savings.”