By I’ve had my geothermal heat pump for the past two years now. So far, it’s been helping me to reach my net zero energy goals in my new house (or maybe I should say my “not so new” house now). But getting it installed meant drilling a 400-foot-deep well in my backyard, running a cooling loop into the house through the foundation, and getting everything hooked up inside the house. It’s a little more complicated than your standard air source heat pump setup … and a lot more expensive, too.
But was it worth it? I’ve learned a lot over the past two years, and I’ve collected a bunch of data, too. So what can you take away from my experience? And is there anything I’d change if I had it to do over again? Let’s dig into it.
Before I dive into my personal thoughts and whip out my collection of charts, let’s do a super fast recap of what a geothermal heat pump even is.
How’s it work?
In the world of physics, the conservation of energy is law. In a nutshell, the energy within a closed system must remain constant. You can’t create or destroy energy. You can only move it. At a surface level, heat pumps seem to defy this rule because you can get three to five times more heat energy out of a heat pump for every kW of electricity you put into it. But it’s not creating heat energy. It’s only moving it. You’re essentially using one watt of electricity to move three to five watts of heat.
Heat pumps do this using a fluid called a refrigerant that absorbs heat from the outside air. That refrigerant gets compressed, which raises its temperature even higher. Then it releases that heat into your home through a heat exchanger. Heat pumps can also operate in reverse to chill your house, just like an air conditioner. They move the heat from inside your home back to the outside air. In essence, a heat pump is simply a series of heat exchangers, moving heat out of the house during the cooling cycles and heat into the house during warming cycles.
A geothermal heat pump is doing the same exact thing, except it’s moving that heat from deep in the earth through liquid inside a loop into the house. Just like any other type of heat pump, it can also do the reverse and move the heat from the house deep into the earth. The big benefit of geothermal loops over air source heat pumps is the efficiency at much colder operating temperatures. It doesn’t matter if the air temperature is 20 below outside because when you go deep enough into the earth, the temperature stays pretty constant.
In my area, once you get down to about six to 10 feet below the surface, the earth becomes a consistent 50 F (or 10 C). But an air source heat pump at those same frigid, 20 below, air temperatures would lose most of its efficiency and may struggle to keep your home warm. There’s a nuance to that though, which I’ll get to later.
One bonus feature of many geothermal systems is a desuperheater. This captures waste heat from the system and uses it to preheat water in a holding tank. That preheated water then feeds into your hot water heater, which has to work less hard to reach the final temperature. It’s essentially free hot water from heat that would otherwise be wasted.
With all that in mind, I think that heat pumps are one of the best climate control technologies you can get for your home today. And nothing beats geothermal’s groundbreaking efficiency for heating and cooling your home.
Why I wanted it (and why you might too)
It’s that exact reasoning that drove me towards wanting to get a geothermal HVAC system. I live in Massachusetts, which can get pretty hot and humid in the summer and pretty cold in the winter. No, it’s not as hot as Florida or as cold as Minnesota, but it’s got some wild seasonal swings that mean you want (or need) good air conditioning and heating. Because my wife and I were building our dream home and were planning for the long term — as in 20 to 30 years — geothermal made sense to us.
I’ve said this about my experiences with solar panels, too. If you want to figure out if something is worth it, you have to clearly lay out your goals. These are of course personal decisions, so my goals may not align with yours. But in my case, my wife and I set out to create our energy-efficient forever home.
The upfront costs were significant. There’s no sugarcoating that. But the projected yearly operating costs were less than half what a comparable air source system would run in my area. When you’re talking about a 20 to 30 year timeline, that adds up fast. I’ll get into the actual numbers and how they’ve held up in a bit.
But that leads to the whole point of this video… what has it actually been like two years in?
How it’s been
This being my first time living with a geothermal heat pump, there were a few things that caught me by surprise. I never have to lose my cool about thermostat settings anymore. I never touch it … ever. In every house I’ve lived in up until now, I’ve had thermostats that worked on timers or where smart thermostats adjusted things on the fly. For instance, in the winter you might keep the temperature at 72 F (22 C) when we’re home, but drop it to 65 F (18 C) when you’re away at work. Sometimes it’s worth it to do the same thing overnight while you sleep.
When it comes to most smart thermostats, they have a feature that’s called “adaptive recovery” or “smart recovery.” This is where the thermostat learns how fast your HVAC can respond to temperature changes and will start to heat or cool early enough to reach the desired set point at the exact scheduled time you set. If you want your home to be at 72 F (22 C) at 7:00 a.m., the thermostat may kick on your system at 6:40 a.m. because it will take roughly 20 minutes to hit the desired temperature.
Well, for geothermal systems, you actually don’t want to do any of that.
Geothermal HVAC systems are best run with little to no temperature setback because the ground loop provides a powerful buffer. Its high thermal inertia means it absorbs and releases heat gradually, thanks to the earth’s stable underground temperatures.12 This makes the system slower to ramp up or down in response to big temperature changes. That may sound like a downside, but it’s actually a benefit. The result is a highly efficient and comfortable constant temperature that also reduces wear on the equipment. That’s because the system isn’t cycling on and off or trying to play catch-up like conventional air-source systems.12
I was originally disappointed that a smart thermostat like Ecobee wasn’t recommended for my WaterFurnace system. But it turned out I didn’t need one. The built-in app handles everything, and because I’m not adjusting temperatures anyway, a third-party thermostat wouldn’t add any value.
This is the most comfortable house I’ve ever lived in when it comes to temperature. A big reason for this is the incredible insulation and airtightness, but the geothermal system plays a huge role too. I keep it set between 72 and 75 F (22 – 24 C) year round. We only drop it when we’re on vacation for extended periods. Even with the system running at a constant temperature, it uses dramatically less than an air source heat pump would.
Now, for some actual numbers. Here’s the deep dive on costs.
Let me preface my figures by saying that geothermal systems can give you a little bit of sticker shock when you price them out. The actual costs will vary wildly based on where you live. I know the costs of getting a system installed in the U.S. Midwest could be as little as a third of what I paid here in Massachusetts, so don’t take what I paid as a surefire indicator of what it would cost you. Also, I’ve mentioned this in previous videos, but for full disclosure WaterFurnace did supply some of the system for me. This isn’t a sponsored video for them and
Before any kind of incentives or rebates, the total cost of my system was $78,000. Some of this cost was because this was a brand new home install with all-new ductwork. $18,000 of that cost was just drilling the 400-foot well in my backyard. Again, there are other ways you can install a ground loop for geothermal that can greatly reduce that cost. But for my setup, this is what it was. After the federal rebates, the system cost came down to about $54,000. If this had been a retrofit instead of a brand new house install, state rebates would have brought the cost down to about $39,000, which would have been the cost of a comparable air source heat pump in my area that I priced out.
Here’s where the benefit of geothermal kicks in: yearly operating costs. The theory going into getting this geothermal system was that it would cost around $950 a year to run, which included hot water production through that desuperheater I mentioned earlier. Air source would cost around $2,100 a year to run. You’re talking tens of thousands of dollars in savings over 10 to 20 years, if not longer.
Without factoring hot water, my HVAC system cost about $697.49 to run the first full year. Year two cost about $702.47. That’s an average of $60.20 per month.
Putting hot water production back into the mix, it would have cost $949 in year one and $954 in year two. That’s an average of $90.06 per month. The prices I’m quoting here are based on the average electricity price in my area starting two years ago, which was about $0.31. If your electricity prices are different from that, it should be easy to recalculate to see what it might have been for your area.
The system performed on solid ground, hitting those projections almost dead on. That’s incredibly validating.
But here’s the part that really puts this in perspective. My server rack is really heating up my energy bill. I run a business out of my house and have a substantial homelab and network rack setup in a hallway closet. That thing consumes 17.8% of my total energy use. My HVAC system? Just 14.8%. My home office tech setup uses more power than heating and cooling my entire house. That’s more than my EV charging too at 11%. That’s pretty low, though, because I mainly charge my EV off excess solar production.
For comparison, heating and cooling typically accounts for about 52% of a home’s yearly energy use in the US. Even if you remove my computer setup and EV charging from the mix, my HVAC is still only 20.8% of total energy use.
Maintenance has been pretty down-to-earth…even if the initial investment might seem sky-high. Turns out that the cost of maintaining my geothermal system is basically the same as the natural gas HVAC system I had at my previous house. I have my installer come out at least once a year to check on the system, change out the air filter, and maybe top up the loop fluid. Super easy.
But the cherry on top for me is that I have solar and home batteries installed, which generates more electricity than I use over the course of a full year. So at the end of the year, the actual operating cost of my HVAC and hot water setup is, well, it’s basically zero. I can’t say it’s actually “zero” because I do still have an electric bill of about $150 to $200 a year because I’m grid tied and still have service fees. So if you want to get pedantic, we could calculate the actual rough cost. My geo’s 14.8% energy use of $200 per year is $29.60, or $2.47 per month to run.
Smart home fun
Here’s a quick tangent on my computer setup, because some of you might be interested in my nutty network rack in my hallway closet. I have a Mac Studio running as a homelab server with docker containers for self-hosted services like Immich for photos and Karakeep for bookmarking articles. I’m also running a virtual machine for Home Assistant.
If you’re interested in optimizing your home’s energy use, tracking solar production, controlling EV charging, or monitoring water usage, you really should check out Home Assistant. It runs on pretty much any computer and is completely free and 100% local. No cloud necessary.
Home Assistant has a built-in energy dashboard. Just plug in your solar panel, battery, and home water management trackers. I use Enphase for solar, which was easy to integrate. I also have Span smart electric panels integrated through HACS. That’s the Home Assistant Community Store, basically community-created plugins for anything Home Assistant doesn’t natively support.
Once you set up your energy trackers, you get a beautiful dashboard showing daily energy use and distribution. I have a PV forecast plugin that adds a dotted line showing predicted solar production. Below that are bar charts showing which trackers used the most energy. At the bottom is a Sankey diagram visualizing where energy flows from and to. That’s my favorite view.
But you can do so much more. I’ve built custom dashboards showing real-time and daily energy use. Even though I can’t control my WaterFurnace system through Home Assistant, I still get all the telemetry data. I can monitor loop temperature, daily energy use, and individual component consumption. This is handy for testing configurations like running the fan constantly versus on-demand.
I’ve also gone full obsessive…because I have air quality sensors in every room. One dashboard displays temperature, humidity, and CO2 levels for each space. I’m even tracking temps in my attic spaces. But that’s a geek-out for another day.
But the real power kicks in with automation. For a while, I had a routine that tracked house energy use versus solar production. If my panels produced more than the house needed, it would turn on the EV charger. If production fell, it switched off. It wasn’t perfect, but it brute-forced a “solar-only charging” setup. I’ve since replaced that with a new Span panel feature that does the same thing more elegantly.
I’ve also experimented with automated shade control. All my Lutron shades can automatically lower when the sun beams in during the hottest parts of the day. The automation considers time of year, room temps, and user preference. That last part is key for spousal approval. If my wife opens a shade back up in the den, the system overrides itself for a set period.
It’s definitely a deep rabbit hole you can fall down, so be careful…although I find it a lot of fun.
Is it worth it?
So, is geothermal worth it? Well, it certainly was intertwined with what I wanted. But as a general recommendation for any of you out there, it’s complicated.
It shouldn’t be a surprise, but based on my long-term goals with my whole house, yes, it was worth it. One of my biggest goals was to be as energy independent as I could get, which meant zeroing in on net zero. A big way of achieving that is not just tossing more and more solar panels onto your home, but aiming to be as energy efficient as you can be with the appliances and devices you put into the home. It’s kind of meeting in the middle. The geothermal setup was a key way to keep my energy use as low as it is.
But this isn’t without its drawbacks. Is there anything I would have done differently? Yes — a couple things. Our system is actually oversized for our house. The WaterFurnace unit is variable speed, so it didn’t matter too much, but we might have squeezed out a little more value with something smaller.
The bigger issue is that my office and studio are built off the back of the garage, so they aren’t technically part of my factory-built home’s main thermal envelope. The walls were constructed and insulated onsite instead of at the factory. While these rooms are heated and cooled by the same system, the rooms themselves don’t maintain as consistent of a temperature as the rest of the house. In the summer, it’s a couple of degrees hotter than the rest of the house, and in the winter, it’s a couple of degrees colder. It’s not bad at all, but it’s noticeable. If I could go back and do it over, I might have had a mini split installed just for these two rooms and kept it separate from the rest of the house. That would have allowed me to dial things in and only run the system when it’s necessary back here.
Where I live in Massachusetts, this process was extremely expensive upfront. However, federal, state, and utility rebates can dramatically reduce those costs and get things much closer to a comparable air source setup’s cost. Plus, you have options. Companies like Dandelion Energy that install geothermal systems in the northeast of the U.S. have very small, nimble drilling rigs that can fit into tighter areas for drilling. This not only helps to install these systems in more locations, but it can sometimes help reduce the overall installation costs. If you have the room, going for a horizontal ground loop can be much, much cheaper than drilling.
At the end of the day, though, it all comes back to your personal goals. Air source heat pumps are amazing and the technology is continuing to improve. Newer cold climate heat pumps have impressively wide temperature ranges that they can operate in. Variable speed mini split systems are extremely cost effective for retrofits. Bottom line: if you’re focused on a shorter term time scale, like finding the best value for your home for the next eight to 10 years, you might want to focus on those air source options over geothermal.
As for me, I am extremely happy with the comfort I experience throughout the whole house. The system is performing better than I projected, and we’re on track to recoup the costs in operational savings just like I originally projected in a previous video. Would I recommend geothermal? Yes, with caveats. It depends on whether you’re ready to stay grounded for the long term.
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