TL;DR
- Pre-install: 1,300 kWh/mo, $200/mo electric bill.
- Post-install: ~$60/mo electric bill — a $140/mo ($1,680/yr) savings.
- Plus: Two Antminer S19J Pros produce an estimated $420–$600/mo net of energy.
- Net monthly benefit: ~$560–$740 before hardware amortization.
- How: 8 kW DC solar + Enphase microinverters (no battery), plus a Texas retail plan with a free-nights tier. Miners run only during the free window.
The hook: I’m not a miner. I’m an electrician.
This isn’t a “quit your job and mine crypto” story. I ran the wire in my own garage, which is normal for a Tuesday. Then I did the math and realized that the same free-nights plan I was using to kill my electric bill could be used to run a pair of ASIC miners at zero marginal cost.
Most solar salespeople won’t pitch this because:
- They sell batteries and panels, not arbitrage strategy.
- The Bitcoin piece scares their compliance department.
- It requires a Master Electrician on the miner branch (80A+, dedicated subpanel, code-compliant cooling). Most of their installers are Journeyman-level; adding a 12 kW dedicated ASIC circuit is not in their wheelhouse.
I happen to be the Master Electrician, and I’m publishing the whole system so you can decide if it’s worth doing at your house.
The house: a 1,200 sqft baseline
Before any of this:
Home
1,200 sqft single-story, Texas. In-ground pool with variable-speed pump. One 4-ton central AC (16 SEER).
Consumption
1,300 kWh/mo average. $200/mo on a flat-rate retail plan at ~15¢/kWh all-in.
That’s a normal Texas summer bill. The pool pump alone runs 6–8 hours a day; the 4-ton AC dominates the rest.
Rick's Verdict
1,300 kWh/mo is right at the Texas average. The strategy below scales with usage — if your bill is smaller, your dollar savings are smaller, but the ratio stays roughly the same.
Step 1: 8 kW of solar, no battery (yet)
I installed 8 kW DC of rooftop panels on Enphase microinverters. Grid-tied, no battery.
Why no battery? Two reasons:
- Texas net-metering rules make battery payback longer than it looks on the sales sheet. We’ll cover the ITC + buyback-rate math in the Texas battery ITC article.
- The arbitrage play at the heart of this system requires the grid, not a battery. A battery would actually make the miner-on-free-nights strategy less efficient.
The 8 kW array produces roughly 1,100–1,300 kWh/mo here in Texas — enough to cover most of my daytime baseline. Enphase microinverters were the right call because the roof has two orientations and partial shading from a pecan tree. Microinverter vs. string inverter tradeoffs are covered here.
Step 2: switch to a Texas free-nights retail plan
Texas is deregulated. You pick your retail electric provider (REP). Several offer a “free nights” tier where, in exchange for a higher daytime rate, you pay $0/kWh during a window (commonly 9 PM – 6 AM or 8 PM – 5 AM).
Most people who sign up think, “great, I’ll run laundry at night.” That’s leaving 90% of the value on the table.
Here’s what the plan looks like in practice:
| Window | Rate (typical TX free-nights plan) | Who’s running |
|---|---|---|
| Free window (e.g., 9 PM – 6 AM) | $0.00 / kWh | Miners, EV charger, pool pump, laundry, dishwasher, AC pre-cool |
| Daytime | ~$0.18–$0.22 / kWh | Solar covers baseline; grid only when the sun’s down or cloudy |
Exact plan I use: [NEEDS: Rick to confirm EXACT retail provider name and plan name, e.g. “Gexa Eco Saver Plus 12” or similar]
Rick's Verdict
Before you sign up for any free-nights plan, pull the Electricity Facts Label (EFL) and look at the daytime rate. Some plans bury a 25¢+ daytime rate that eats the savings if you don’t shift load aggressively. My rule: the free-window rate has to be $0 flat, and the daytime rate has to be below 22¢/kWh all-in.
Step 3: add two Antminer S19J Pros on timers
Each Antminer S19J Pro pulls ~3.05 kW. Two of them is ~6.1 kW continuous, or about 55 kWh per 9-hour free-nights window.
On a flat-rate plan, 55 kWh/night × 30 nights × 15¢ = $247/mo just in electricity, before the rest of the house. That would kill any mining profit.
On my free-nights plan, the same 55 kWh/night × 30 nights × $0 = $0. The miners run inside the electric bill, not on top of it.
The wiring:
- Dedicated subpanel fed from the main service — 100 A breaker, #3 AWG THHN in EMT conduit.
- Each miner on its own 30 A, 240 V branch circuit. (S19J Pro needs 220–240 V for best efficiency.)
- 240 V smart timer relay (Kasa KP405 for one, plus an Aeotec for the 240 V side — there are better industrial options but these work).
- Exhaust: louver + inline duct fan to outside — ASICs put off serious heat. Do not run these in a conditioned space.
The relay cuts the miners off at 6 AM sharp. They spin back up at 9 PM. If you forget this piece, you’re back to paying 18¢/kWh during peak — and you’ll lose money faster than you’re making it.
Want the one-page wiring diagram?
I'll email you the exact subpanel wiring + load calc I used, free. Plus weekly field notes you can't find anywhere else.
Rick Laughhunn — Texas Master Electrician, NABCEP-certified solar installer. Privacy.
The monthly math (real numbers)
Here’s how a representative month rolls up:
| Line | Before | After |
|---|---|---|
| Grid usage | 1,300 kWh | ~2,150 kWh (house + miners) |
| Billable kWh (after solar offset + free-nights window) | 1,300 kWh | ~300 kWh |
| Electric bill | $200 | $60 |
| Monthly savings on electricity | — | $140 |
| Miner revenue (net of energy) | — | $420–$600 [NEEDS: most recent 3-month avg from Foundry USA / Luxor pool payouts] |
| Total monthly net benefit | — | $560–$740 |
This is before hardware amortization (panels, microinverters, subpanel build, miners). Depending on equipment cost, full payback is usually 3–5 years.
Rick's Verdict
Miner revenue is volatile. When BTC network hashrate goes up or price drops, your payout drops. The electric-bill savings ($140/mo, rock-solid) are the floor. Treat mining revenue as bonus, not base case.
What could go wrong (and how to design around it)
1. Free-nights plan pricing changes
REPs repriced heavily after the 2021 Winter Storm Uri. Your plan can change at renewal. My defense: 12-month term, auto-reminder to re-shop at month 10. If rates jump, you idle the miners until the math works again.
2. AC tripping on startup
Adding 6.1 kW of continuous load to a 200 A service is usually fine, but you have to do a real NEC Article 220 load calc before you sign off. If your AC compressor locked-rotor amps + the miners + baseline puts you over 80% of service capacity, you need a service upgrade or a smart load-management device (e.g., SPAN panel or SolArk Home Energy Manager).
3. Heat and noise in the space
S19J Pros are loud (75–80 dB, like a running vacuum cleaner 24/7) and they dump 11,000 BTU/hr each. Detached garage or outbuilding is the right play. Inside the house is a non-starter.
4. Insurance and code
Most homeowner’s policies don’t exclude ASIC mining, but call your carrier. NEC compliance requires a permit. If you’re not comfortable pulling one, hire a Master Electrician (hi).
Is this a fit for your house?
Quick filter:
Go if:
- You’re in a deregulated Texas market (Centerpoint, Oncor, AEP, TNMP TDUs).
- You have 200 A service and at least 40 A of headroom.
- You have a detached garage, shop, or outbuilding.
- You can afford the $7–12K ASIC + wiring upfront.
Don’t go if:
- You’re in a regulated-utility state (no retail choice, no free-nights plans).
- You can’t tolerate noise.
- You’re expecting miner revenue to pay the mortgage — it won’t.
Next steps — 4 things to do this week
- Pull your last 12 months of electric bills. You need the kWh pattern, not just the dollar amount.
- Shop your retail plans. powertochoose.org is the official TX comparison site. Filter for “free nights” or “free weekends”.
- Run the battery payoff calculator to see if adding storage makes sense on top of this (it sometimes does).
- Join the forum. Ask me questions on solarbatterytips.com/forum. I answer every one personally.
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Rick Laughhunn — Texas Master Electrician, NABCEP-certified solar installer. Privacy.
Rick Laughhunn
Licensed Master Electrician (Texas) · NABCEP-Certified PV Storage Installer · 20+ years in residential electrical + solar.
Rick runs every system in this article inside his own home in Texas. If you want the exact parts list or a second opinion on your own design, email rick@solarbatterytips.com or post on the forum.