How My Home Battery Really Performed (2 Years Later)

Sep 8, 2026

12 min read

Author Matt Ferrell

Coauthor

Video Editor Sunny Natividad

Consultant

This is my electric bill from January. I have solar on the roof and 20 kWh of battery bolted to my garage wall. Even with all of that the Eversource bill came to $336. And banked sunshine from last summer paid a $166 of it. Then the credit bank hit zero and my next bill came entirely out of my pocket.

Here's the part that took me two years and a spreadsheet to work out. Every dollar of that rescue came from the panels on the roof. The battery didn't help.

I pulled twelve months of my own utility bills and ran them against twelve months of data from the panel that meters every circuit in my house. Then I ran those same twelve months again with the battery deleted. My battery costs me about $207 a year in electricity and has never saved me a dollar. Not once.

And I'd buy it again tomorrow.

I know exactly how that sounds, but stick with me here. By the end of this you’ll know why, and then you can decide whether my reasons align with your reasons. There’s also something I realized I got wrong about my electric bill that I stated in a previous video two years ago.

So what did I learn about home batteries after living with them across two homes over 6 years? And are they worth it?

Quick bit of history, because it matters more than it looks like it does. In my old house I had one Tesla Powerwall. Tesla's referral program gave me the hardware for free, but I paid the installation costs. I’ve covered it in previous videos.

That meant I had to estimate the total overall costs whenever I tried to calculate the payback number from my previous house. It was always a ballpark estimate because of the referral program.

But this time I paid for the whole thing. Four Enphase IQ 5P batteries, which means 20 kWh of storage and 15.4 kilowatts of output.¹ $33,407 all in before any rebates.

The federal tax credit took 30% off and Massachusetts kicked in a $1,000, so the net cost was $22,385.² ³ That's $1,119 for every single kilowatt-hour hanging on that wall. I financed it with a MassSave 0% HEAT loan. It’s a great program that Massachusetts runs to offer low or no interest loans for home energy upgrades on things like HVAC heat pumps to home batteries.⁴

Again, nobody sent me these batteries, so there’s no sponsor. That's my money on the wall.

And here's what I thought I was buying: keeping those electrons generated on my roof in my house to help keep our electric bill low. Also, the ability to shrug at a power outage. There’s more to that, but only one of those turned out to be real.

What it actually does

Before we get to the money, return on investment, and all the other reasons you might get a home battery, here's what this thing does on an ordinary Tuesday.

Taking the last eighteen months of data off my Span smart electric panel gives some interesting insights. On a median day the battery discharges 11.3 kWh. Over the last complete year it moved 3,673 kWh into the house.

Here’s the key thing to keep in mind: the season decides everything.

In January my solar panels generate about 20 kWh a day, while my house eats 52. Yes, that’s a lot, but remember that my house is all electric with an EV, heat pumps for heating and hot water … everything. There's no excess electricity generation to store, so the battery only moves 6 kWh or so a day.

However, in July I make 61 kWh a day and use 58, which results in the battery moving about 14 kWh. One quick clarification on my setup is that I keep my battery system set to a 20% battery reserve, which means my total usable daily capacity isn’t 20 kWh … it’s 16.

Now, let’s do some division. Who likes some math? 3,673 kWh a year, over 16 usable kWh, is 230 full battery cycles a year. My warranty covers 6,000 cycles or 15 years, but at my rate I won’t hit 6,000 cycles until year 26.¹ It’s kind of like a car warranty. Your car may come with a 150,000 mile warranty, but if you only drive 4,000 miles a year the warranty will expire by its time limit first. I’m like that little old lady who only drives her car to church and back once a week.

So this battery is going to age out long before it wears out. I wish I could say the same thing about my knees. That sounds like good news, right? It's actually the whole monetary problem because every dollar I spent has to spread across a very small pile of kWh.

And that pile is smaller than I told you it was. Two years ago I sat right here and explained how my electric bill works, and I got part of it wrong. I didn't find out until I pulled the latest twelve months of statements for researching this video.

The bill

Let's go slowly here … more for me than you.

My meter keeps a tab. One counter for kWh coming in from the grid, one for kWh going out. Eversource subtracts one from the other once a month, and everything on my bill is computed on the difference. The bill makes it pretty clear: consumption of 1,181 kWh, minus 143 for generation, nets 1,038.

Then watch what happens to that 1,038 kWh. Both the supply and delivery charges are computed on 1,038. Every kWh I exported cancelled a kWh I imported … delivery charge included. In Massachusetts, that means about $0.32 of value for each one. That's a real one-for-one trade.

And it's always worked that way here. So what does the battery do to any of this?

Take July of last year, a month where I sent out far more than I took in. With the battery, I imported 853 kWh and exported 1,420. Without it, I'd have imported 1,361 kWh and exported 1,999. The battery cut both sides by roughly the same amount, so my net barely budged, and I came out $18 worse off.

Now let’s look at a month where I owed money, December of 2024. With the battery I paid $231.07, which is exactly what Eversource billed me. Without it the cost would have been $192.62, which means the battery cost me $38.

This type of thing is happening every single month.

Across the last twelve months, the battery cost me $207. And the reason is almost embarrassingly simple. With every kWh I run through the battery I lose about 16% as heat. 714 kWh a year … gone. The cars in my garage might be slightly cozier because of that, but my wallet is not.

Under a flat electricity rate like mine, along with basically 1 to 1 net metering, the grid is a better “battery” than my battery. It's virtually 100% efficient.

I told you this two years ago, and I was wrong

Two years ago I told you Massachusetts credits your exports at the generation rate only, so you eat the delivery charge on everything you send back. And I said the battery helps you dodge that. Many states in the country operate that way, so in those locations, that’s 100% true.⁵

But in my specific case, only half of what I said was true. In early 2024 my credit really was about 54% of retail, which certainly looks generation-only. Then in February of 2025 it jumped to 85%, and today it matches supply plus distribution plus transmission almost to the penny. My export terms improved by more than half and nobody told me. I only found it because I keep a spreadsheet. In case you couldn’t tell, I’m kind of a nerd.

But the conclusion I drew was wrong back then. There is a haircut happening on the net-metering credit for me. It's about $0.048, and it only touches the surplus that spills into the credit amount that builds up over the summer months. My battery couldn't capture it either way.

Here's the number nobody selling you a battery will put on a slide.

What a stored kilowatt-hour costs

Let's put a price tag on a stored kilowatt-hour.

Start with the net cost of $22,385. Spread it over everything the battery will deliver in 20 years at my usage level, which is about 64,000 kWh. That number assumes the battery loses about 1.5% of its capacity every year, which is what the published data on this chemistry actually shows.⁶ ⁷ That's $0.35 a kilowatt-hour just for the hardware. This is not accounting for my solar panel setup, just the battery by itself. But when we do account for the solar I’m generating we have to account for the cost of charging the battery. Every excess kilowatt-hour I put into the battery is one I could have sold back to the grid for $0.28. Because I lose 16% in round trip efficiency, that works out to another $0.33 for every kilowatt-hour I get back out.

$0.68. That's what one kilowatt-hour out of my battery costs me. The one it replaces is worth $0.28, and I can buy one off the grid for $0.32.

I'm paying more than double the grid price to store electricity I already own, and a longer battery life doesn't rescue it. Stretch it to 25 years and it only falls to $0.62, because the cost of filling it never changes.

So where did the money come from?

Before you jump into the comments and try to dunk on home batteries in general, or especially on my setup, there is money in this system and It comes from exactly one place. My utility rents my battery.

It's called ConnectedSolutions. Every summer between, June and September, there’s 40 or so afternoons that Eversource sends a signal to my battery to dump its power into the grid. The sessions last for 2 or 3 hours right around the 5:00pm crunch.⁸ Enphase pays $275 per average kilowatt delivered, and passes a 100% of that money from my utility to me.⁸ ⁹ Some companies … Tesla … don’t because they take a cut.¹⁰

How’s it work out? In 2024 I earned $1,881.38, and in 2025 $1,634.35. Why was one year 13% less?

Both years my battery dumped essentially the same energy per event, about 14.5 kWh. What changed is how long the utility stretched it out. The program pays on average kilowatts, not kWh. Basically, you get paid for how fast you can empty your bucket instead of how much water was in it. Same energy over 2 hours scores 7.3 kilowatts. Over 3 hours, 4.8 kilowatts. In 2024, 82% of my events were 2 hours. In 2025, only 55%.

Same battery, same job, but a third less money … and I have zero say in it.

Which brings us to the real question: does a home battery make financial sense? If you take the $207 a year my battery costs to run out of the ConnectedSolutions income, I’m netting about $1,550 a year if I average the first two years. My enrollment runs 5 years, but my understanding is that you might be able to re-enroll.⁸ If my participation ends after 5 years, this battery recovers about 20% of its cost over 25 years, and then bleeds $200 a year forever. If it renews beyond the 5 years, it might pay for itself in year 15.

The whole answer is kind of fuzzy on what’s going to happen down the road.

So when looking at the finances and ROI of a home battery, the math is saying no … not worth it. So here's the question I've been dodging for the past ten minutes. Why don't I regret this? Why on earth would I do it all over again?

That’s because this isn’t an investment decision. I’m not deciding what stocks to buy or where to invest my money for a financial return. Ask yourself: what does a battery do? What’s its function and purpose that you want it for? Do you buy a lawnmower because it’s an investment or because it serves a task?

For instance, look at my emergency backup history. Over the past 26 months I’ve had 10 outages for a total of 51 minutes. Out of those the longest one lasted 11 minutes. On its face it sounds like spending over $22,000 for 51 minutes of backup is an insane decision.

But here's what actually happened during those ten outages.

Nothing.

We didn't notice. There were times we were running on backup and had no clue. No flicker, no beeping, no clocks blinking at us the next morning. I found out afterward from the log or a phone notification I had missed.

The squishy reasons

And that's the thing the spreadsheet can't see.

Every number in this video is a money calculation, and money is not why most people buy a battery. So let’s talk about my actual reasons for wanting a home battery, contradictions included, because I think the contradictions are the interesting part.

I wanted energy independence. Meanwhile my utility takes the wheel 40 or so afternoons during the summer, and that's the only part of this that pays. My money and motivation are pointing in opposite directions.

I wanted to use my own clean solar power … the power being generated on my roof. To do it, I throw away 714 kWh a year as heat. Storing my own sunshine is less efficient than shipping it to the grid and buying it back.

But I wanted resilience. I didn't size for the worst case scenario. Twenty kWh runs my whole house about eight hours in January if I didn’t do any kind of curtailment. A genuine multi-day nor'easter needs three or four times that. I made a rational call about how much backup I’d most likely need. Going off grid was never my motivation.

If I shut things down to just the critical loads like the fridge, the HVAC, a few lights, and with any January sun at all, I can run indefinitely. That's the Span panel helping me to shape my energy usage during an outage. Most people just install a hardwired critical loads panel to do the same thing, but I’m able to adjust my critical loads in software. I can be more flexible with it depending on what’s actually happening.

The last rationale for getting a home battery tends to trip up everybody. Independence and resilience are two different things. Independence means leaving the grid. Resilience means the grid can stay, it just stops mattering when it fails. I want the second one. Those two get mashed together constantly, and they buy you completely different systems.

EnergySage asked homeowners and installers the same question in the same survey. 67% of installers said people buy batteries for resilience. Only 11% said savings. The homeowners? 30% said rate savings.¹¹ ¹² A lot of people are being sold one story while telling themselves another, and nobody's numbers get checked.

And there's one benefit the whole spreadsheet misses. When my battery discharges at 5:00pm on a 90F day, it's shoving aside the dirtiest power on the grid. Peaker plants are what’s running at that hour.¹³ ¹⁴ Last year my battery pushed six hundred and eleven kWh into the grid across forty-three events, every one of them timed to the filthiest moment of the day. My solar can't do that on its own.

So here's where I land.

I can't tell you this pays for itself, because in my situation it doesn't. What I can tell you is what $22,000 actually bought for a nerdy home owner in Massachusetts.

It bought 10 power outages I slept or worked through. It bought about $1,550 a year, for as long as Eversource keeps renting it. It bought a house that holds its fridge and HVAC through a storm, as long as the sun shows up now and then. And it bought me the ability to stop thinking about winter nor'easters, which, knock on wood, hasn’t impacted me in this house yet. It definitely did in my previous house. I’ve experienced much longer outages … it’s not fun, which is why I’d much rather be prepared with my energy storage backup.

It costs me $207 a year in electricity, and it will very likely never pay itself back.

But … it depends on where you live and how your electricity rates are structured. This was my favorite part of digging into this topic.

While I was pulling bills for this video, I found this. Eversource swapped my meter in February. Western Massachusetts is first in line for their smart meter rollout, a million and a half of them will be installed by the end of 2027, and the entire point of that program is time-of-use rates.¹⁵ ¹⁶ ¹⁷

Time-of-use would flip my energy math from negative $200 a year to somewhere between a $170 and $800 positive, depending on how Massachusetts structures the rate.¹⁸ ¹⁹ It definitely helps, but it still doesn’t make it a crystal clear investment. The program renting my battery still does that.

But here's the part I fixated on. A better peak rate wouldn’t help my battery, but my utility paying me less for the excess solar power I send back would. Right now the grid is a perfect virtual battery for anyone that lives in my area with solar. It's free, and it never loses a thing. That's exactly why my battery can't win. The policy change I'd normally be complaining about is the one that would vindicate the purchase, and honestly, be more fair to all the non-solar home owners and renters in my area. Yes, I’m advocating for not having 1 to 1 net metering. I think it’s more fair to have generation only credits for solar home owners. Come at me in the comments if you disagree.