By So, it’s been a full year since I installed these solar panels and a large home battery on my new house … and I’ve got some news. They say solar power can save you thousands on energy bills, but what actually happened. This past year was a bit of a rollercoaster ride from the challenges of getting them installed to seeing how well they handled powering my all-electric house through heat waves, freezing temperatures, and a couple of small power outages. Spoiler alert: solar isn’t all sunshine and rainbows. Was my net zero house ready for all of it? Was I able to achieve net zero energy? And most important … was it worth it? Let’s just say, I learned some pretty surprising lessons that may be of use to you.
So this is the second part to my “What I Learned After 1 Year in My Net Zero House” video. The first part focused heavily on what went into my choices on constructing a factory-built, energy efficient home with geothermal heating and cooling, a heat pump water heater, and more. I’ll link to that one in case you want to see it after watching this one.
My goal is to give you some strategies to keep in mind and possibly try. It’s not that you should do exactly what I did, because everybody’s circumstances are unique. But hopefully, these videos spark some ideas in case you’re interested in making your own home more energy efficient. And, of course, I’ll do my best to answer the lingering question … was all of my effort really worth it in the end? A hint on that: we produced more energy over the course of the year than we used, so we comfortably achieved net zero. However, there is a little bit of a gotcha I discovered on how that works out financially and with my utility.
What We Installed
But first, what did we install? We went with 43 REC Alpha 400 watt panels, giving us a 17.2 kW system. Most panels face south, while a few on the front face west to capture late afternoon and evening sun. This setup is estimated to produce almost 18,000 kWh per year.
We paired the panels with 20 kWh of Enphase IQ 5P batteries—not quite enough for 24-hour use at full power, but plenty to keep things “current” in an emergency for essential needs (like the fridge and HVAC). There’s a whole backstory on why we went with 20 kWh instead of 25-30, but I cover that in another video.
And the price? Let’s just say it wasn’t cheap. The solar panels were $55,384, and the batteries were $33,407, totaling $88,791. I break down all the pricing details in previous videos, which I’ll link in the description, along with one on the general costs of solar. I’ll get into the final “out of pocket” cost later.
To optimize and monitor energy use, we installed a couple of Span Smart Panels for circuit-by-circuit usage data. Home Assistant powers the home automation setup, with a dashboard that combines data from Span, Enphase, and Phyn water tracking. It’s a great way to monitor and automate our energy use.
We’ve also installed Lutron Diva dimmers and switches along with motion sensors to automatically turn off lights when rooms are empty and set up custom lighting scenes. The Lutron Serena shades are programmed to adjust based on the time of day and incoming sunlight, helping control indoor temperature—even when we’re not home. And yes, the Lutron system gets high spouse approval … and cat approval, too.
The Reasoning
Before diving into the crazy high costs, it’s important to consider a key point: deciding on solar (or any tech) requires clarity on your specific goals. Solar isn’t a one-size-fits-all solution. Some might say it’s a scam that never pays off, while others claim everyone should have it—but neither extreme is true. It’s a highly individualized decision that depends on your unique situation.
In our case, we built this house as our forever home, so we made choices with a 30-year timeline in mind. That’s why we invested in a super energy-efficient house design; it’s a decision we believe will pay off financially and enhance our quality of life over time. We also built a single-story layout, not just for aesthetics but for long-term accessibility, so we can age in place without worrying about stairs. And we wanted to keep monthly operational costs steady, regardless of future energy prices or inflation. Achieving net-zero energy production was key to ensuring stability and energy independence, especially in emergencies like storms.
I see my house as a whole system—not just the solar panels and battery, but how they interact with the home’s energy efficiency, the geothermal HVAC, hot water production, and EV charging. Everything is interconnected.
Solar performance
So, how did solar perform in the first 12 months? Well, my system produced 18.1 MWh, right in line with estimates from my installer and my own pre-install calculations. For those considering professional installation, I cover my approach in detail in my Achieve Energy Independence course, which you can find on my website. If you’re a “do it yourselfer” when it comes to solar, this guide isn’t really for you. But if you’re considering hiring an installer like I did … it can be a huge help. I’ll put a link in the description if you’re interested.
According to my Span Smart Panel, my house used around 15.8 MWh (Enphase logged it closer to 16 MWh), so we easily met our net-zero energy goal with room to spare.
Month-by-month, I was extremely surprised by winter performance, especially in November and February, which generated more than expected. November was just under our energy use, and February even produced a surplus. Who knew February would be “warming up” to solar? The way this works out financially is also interesting, but I’ll get into that in a bit.
House Performance & Costs
First, as I mentioned before, it’s important to look at how everything performed to really understand if the costs were worth it. For that we need to look at how solar paired with the performance of our geothermal system and hot water production—two of the biggest energy consumers in most homes.
In previous videos, I shared that I spent $78,000 on our geothermal HVAC system, which includes hot water. The bulk of this cost came from drilling the geothermal well. It’s a well that goes deep… into the budget. Thanks to a 30% federal tax credit for geothermal, our effective cost dropped to $54,600—comparable, but still more expensive than, an air-source heat pump we considered at $38,000. If I’d retrofitted an older home, I could have also received a $15,000 Massachusetts rebate for switching from natural gas to geothermal. In my case, though, as a new house, the geothermal system still played a role in an energy efficient new build program. This wasn’t just for the geothermal, but also the airtightness and insulation levels of my home. That rebate also worked out to $15,000. Taking that into account, it makes the effective cost of my geothermal system $39,600, which isn’t far off from that air source heat pump system.
Even without the state rebate, the difference between the systems is $16,600. Over the year, our geothermal used around 2,260 kWh, or $58.39 per month at $0.31/kWh, totaling about $700.69 per year if I didn’t have solar.
Since our geothermal system includes a desuperheater, it preheats our water, reducing the load on our heat pump water heater. The water heater itself used about 818 kWh for the year, or roughly $21.14/month, totaling $253.68 annually at local rates.
Because I’m a super nerd and love data, I collected historical electricity rate data for Massachusetts going back 34 years and calculated the average rate it increases each year. It’s about a 3.28% increase on average. If you plot that out over the next 30 years, you find some interesting trends for everything in my house.
I compared my geothermal heat pump water heater combo to a standalone heat pump water heater. My current hot water cost is $253.68 per year, which I expect to rise to $339.18 in 10 years—the likely replacement timeframe. A standalone heat pump water heater would cost around $481 per year now, climbing to $643.12 in 10 years. A traditional electric water heater would cost $757 per year now and $961.89 in 10 years.
Over a decade, my geothermal setup will save $2,639.87 compared to a standalone heat pump water heater, or $4,545 compared to a standard electric heater. That’s just nuts.
My HVAC and hot water system currently costs about $954.37 per year to run, while the air source system with hot water that we considered would have cost $2,121 per year. Without the $15,000 state rebate, the return on investment between the two systems would break even in about 11 years. But from year 12 to 25 (a reasonable lifespan), the geothermal system could save us an impressive $27,321.13.
If you do start off counting that $15,000 rebate, the two systems are essentially the same cost right from the start. By year 25, my geothermal system will be $42,321.13 ahead of the air source system.
Of course, these electricity costs are theoretical for me since I’m net-positive with solar. Essentially, by installing solar, I’ve “prepaid” for electricity over the next 30 years, fixing my costs and protecting against future rate hikes. So, my return on investment really hinges on the solar system cost.
I’m taking advantage of the 30% federal tax credit and a $1,000 Massachusetts credit for solar and battery installs, which lowers the effective cost to $61,153. Plus, the Massachusetts SMART program, a renewable energy credits system based on grid contributions, should provide around $5,000 over 10 years, bringing my cost down to $56,153.
I’m also enrolled in my utility’s Connected Solutions program, which uses my battery to help stabilize the grid during summer peak loads. They pay $275 per average kW used during the summer. Last summer, I participated in 44 events, averaging 6.84 kW, which earned me about $1,881.38. Unlike Tesla, which takes a 20% cut, most participating battery companies, like Enphase, Sonnen, FranklinWH, Fortress, Panasonic, and Sol-Ark, pass on the full amount to customers. Over the program’s 5-year span, this could bring in around $9,407, reducing my effective solar and battery cost to about $46,747.
Without solar, my annual electricity costs would have been $4,875.71. This means my system will break even in about 9 years, and from year 10 to 30, it should save us around $196,030.64.
Because installing solar is like bulk buying your electricity for the next 30+ years, I was curious what the per kWh price would be breaking it up over time. Or basically, what’s the per unit electricity price? My REC panels have a 25 year warranty, but will last well beyond that. The warranty is for at least 98% of output in year 1, at least 92% in year 25 (0.25% degradation rate). 1
Even with a 0.25% yearly degradation, my panels should still produce around 16.8 MWh annually by year 30, down from 18.1 MWh this year. This matches my payback timeline: around year 9 when my solar cost per kWh dips below today’s electricity prices. Given likely rate increases, utility electricity could cost $0.37-$0.38 per kWh by then. And by year 20, my solar’s cost drops to $0.13 per kWh, and by year 30, to $0.09 per kWh. With potential utility rates at $0.76 per kWh by year 30, the long-term savings are clear. BUT … remember that these calculations are unique to my setup. You can’t take that and apply it to your situation since the size, makeup, and cost of the system will be different for you. Installation costs also vary a lot.
But here’s the catch. We still have an electric bill. We still have a $10 monthly minimum charge for our grid connection, which seems fair to help maintain the local grid. But here’s an important detail: in Massachusetts, for every kWh I send to the grid, I get a 1-to-1 net metering credit … sort of. On your bill, you pay a supply fee and a generation fee. That $0.31/kWh price I would be paying here is actually like $0.15 for supply/generation and $0.16 for delivery. It’s not that literally, but just for illustration. That 1 to 1 credit is like wiping out both … up until you go net positive for the month. At that point I get credited for the supply cost only, which amounts to earning a credit around $0.12 to $0.18/kWh.
Right now, I have over $500 in credits on my account, which will help cover December and January bills when solar production drops significantly. Last year, our bill for those two months was around $752.21, so these credits should cover most of it. Realistically, we might only pay $200–300 in electricity annually, which I’m happy with.
This limited credit for net positive generation also makes the battery more financially valuable since storing and using our solar energy locally is the better option. That’s why I’m excited Span rolled out their solar-charging feature for their Span Drive wall connector. I used to do this with Home Assistant, but now it’s seamless—I can charge my EV only when there’s excess solar, keeping as much of my generation local as possible.
Takeaways
So, was this whole endeavor—solar, battery, geothermal, heat pump water heater, heat pump dryer, and more—worth it? To find out, I compared our house’s costs and energy use to a similar, theoretical standard-efficiency home with an air-source heat pump.
Before we had the solar and home battery installed, our house had achieved a HERS rating of 32. A net zero home would hit 0, which I think we’re hitting now. At the time we built this house the local requirements were for at least a 52. As of July this year new houses require a 42 to pass. So keeping the solar and home battery out of this for the moment, yearly costs to run comparable homes:
- HERS 52 (with air): $10,400.20
- HERS 42 (with air): $8,400.15
- HERS 32 (with air): $6,400.12
- My Home (with geo): $4,875.71
Over 30 years, the HERS 32 home saves over $215,000 compared to the HERS 52 home, and about $100,000 compared to a HERS 42. My home (without solar or battery) would save nearly $300,000 versus the HERS 52 and close to $200,000 over the HERS 42 home.
So at the end of all of this, my wife and I do think this was all worth it in the end. It’s been an electrifying experience. The house has achieved our goals for saving money over time, reducing our dependence on the grid and fossil fuels, and all while giving us the comfort we were looking for in our forever home.
Your mileage will vary (or rather, your kilowattage will vary). And on that note, you should check out EnergySage for great articles and reviews of solar and heat pump HVAC equipment. I’ve found them to be an amazing resource when researching for both my previous house and this one. For U.S. residents, my EnergySage portal connects you with local installers and provides quotes for solar and heat pumps without sharing your phone number (you won’t get deluged with random calls). It’s also an affiliate program, so I earn a small commission, but regardless, I find EnergySage to be a great way to easily compare installers side-by-side. Highly recommended.
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