The Boyds Go Geothermal
Temps are falling, but alas, energy costs are not. What does that have to do with home design? Well it turns out that the next great design flex may very well be converting your home to geothermal energy. What the what? Follow along below, and we will explain all.
Peter and Jody Boyd are living in a geothermal and solar powered home in Westport, CT.
What is Geothermal energy?
Geothermal systems rely on the constant temperature of the ground beneath us to heat and cool your home, so you don’t have to burn fossil fuels to stay comfortable. And while it may not provide the dopamine hit of a fun backsplash, converting to geothermal energy gives you several things tile selection can’t: increased heating/cooling efficiency, lower energy bills that are stable because they’re not subject to fluctuations in the cost of oil/propane/natural gas, a sustainable and valuable capital home improvement (ROI!), plus a dash of moral superiority. And who knows, you may actually even appear smarter to others.
The Boyds want you to know that you don’t need a new house to convert to geothermal! Theirs was built in 1934.
How does it work?
Full candor: we didn’t know exactly. So we went in search of answers from local Westport family Peter and Jody Boyd, who installed a geothermal system in their home last year. (Ok full transparency: Pete just happens to be an expert in all things net zero, volunteers with a UN group to accelerate global climate action, teaches at the Yale School of the Environment, and was COO of Richard Branson’s Carbon War Room.) Get ready to de-carbonize with the Boyds!
Pete and Jody explain that a geothermal system uses the constant temperature below the earth’s surface (roughly 55 deg F), to provide heating and cooling in their home. It does this via a system of tubes buried deep in the ground to a depth of 350 feet beneath their driveway. Inside the tubes is a circulated fluid that constantly flows down to ‘catch’ the 55F subterranean temps and bring it in/out of the home via a “loop.” In summer, it helps disperse heat from the home into the ground, and helps heat pumps circulate cooler air inside the home above. In winter it helps heat pumps circulate warmer air in the home to make it cozy, and helps distribute un-desired colder air down into the ground.
For those wondering: when I asked what the circulated fluid is, Pete tells me that it’s a gel made of water combined with food-grade propylene glycol. You could literally eat it. But please don’t.
The Big Dig
Installation is pretty straightforward, but quite a disruption in your yard during the dig! 1-2 small holes, each 10” in diameter, are bored down into the ground to a depth of 350 feet. In addition, they dig a horizontal trench 3 feet deep. Within these vertical + horizontal holes/tunnels, they run plastic sleeves which enter your house at the basement level and connect to the main heat pumps in your basement and/or attic. Each sleeve houses two thick tubes, as Pete describes: “one for gel traveling up, and one for gel traveling down.” In summer, the up-flowing tube carries cooled gel into the home, and the down-flowing tube carries heated gel to distribute it out. In winter, the up-flowing tube carries warmed gel in, and circulates cooled gel out. Electricity powers the whole system via pumps to help move the gel, and a heat pump that heats or cools air accordingly and pushes it through their home via their pre-existing ducts.
For you visual learners:
(Source: https://aeg.design/geothermal-cooling)
Speaking of electricity, the Boyds went one step further and also converted to solar power a few months after the geothermal system was installed. So now they’re powering not only their geothermal system, but also their hot water heater, entire house, back-up battery storage, and charging their electric vehicles from the solar panels. By the way Nerd Alert: the Boyds can view their home’s energy usage and output generated via a handy app on their devices. Jody remarks that Pete enjoys peeking at it all with a little too much glee… But we feel it’s okay to be smug when you’re living in a net-zero house.
The Boyd’s Goal?: a net zero home.
What’s gone: their old furnace, oil tank, big/loud/ugly a/c condenser unit outside, and ditto for their equally noisy back-up generator.
What’s involved with maintenance: Annual filter change.
The Boyd’s suggested steps for going geothermal:
HES: Get a Home Energy Score via a free assessment of your home’s energy efficiency. Who to call for this: Energize Connecticut https://www.energizect.com/energy-assessments/home-energy-score
Get Airtight: based on HES assessment findings + recos, address porous areas in home’s envelope to increase efficiency (ie. close all drafts w/ insulation, glazing, consider new doors or windows as needed).
Go Geothermal: contact Dandelion Energy (the only geothermal installer in our area) at https://dandelionenergy.com/
The Boyd’s Upfront Costs (not including optional new roof + solar install + batteries)
New doors and windows (to make home airtight): $20k
Geothermal install (HVAC replaces oil, heat, and a/c): $52k (after tax credit)
The system pays for itself in 10 years, and lasts 25. The Boyds love how seamlessly the entire thing works (gone are the days of calling multiple service providers if something goes awry). But they also relish the noise reduction of a furnace-less, generator-less life, the increased convenience of one set-point on their thermostat day + night year-round, and the reduction in their monthly bills. And above all, the Boys truly revel in the fact that they’re contributing to a cleaner world to leave behind for their three kids, living in a green home that has universal value to anybody who might live there after them.
For more information, take a look at Sustainable Westport’s residential learning series: https://www.sustainablewestport.org/news/residential-energy-learning-series-going-geothermal/
