A box in the garage starts talking.
It is a Tuesday afternoon in a four-bedroom in Sacramento. The dryer kicks on. The heat pump is already running. Out in the driveway, a Rivian wants to top up before soccer practice. In an older home this would be a coin flip with the main breaker. In this home, a flat panel on the garage wall pulses once - and quietly throttles the EV charger down to 18 amps for nineteen minutes. Nothing trips. No one notices. Somewhere, a utility planner running PG&E's PanelBoost program sees a green dot.
That panel is a SPAN.
The American electrical panel has not had a real software update since the Eisenhower administration. SPAN's bet, since 2018, is that this is no longer acceptable - and that the cheapest piece of grid infrastructure in the country is also the most leveraged.
The panel is the only piece of grid infrastructure you actually own. Make it intelligent, and the rest of the grid gets easier.
- Arch Rao, founder & CEO, paraphrased from MCJ podcast, 2024The boring box in the way.
To electrify a typical American home - add solar, a battery, an EV charger, a heat pump - you usually have to enlarge the electrical service. That is a polite phrase for a $15,000-to-$30,000 trench, a permit, a visit from the utility, and a few months of waiting. Multiply that by 80 million homes and decarbonization stops being a chemistry problem and starts being a logistics problem.
The breaker box, in this story, is the bouncer at a club that is rapidly running out of capacity. SPAN's argument: do not build a bigger club. Hire a smarter bouncer.
You do not need 400 amps to your house. You need 200 amps that know what they are doing.
- Engineering team mantra, repeated often enough to be on a stickerAn ex-Tesla engineer picks an unsexy fight.
Arch Rao spent the second half of the 2010s running product for Tesla's Battery Business Unit, including the launch of the Powerwall. Most founders leaving Tesla Energy go on to start another battery company. Rao went looking for what was getting in the battery's way - and kept arriving at the panel.
This is, on its face, an odd thing to fall in love with. Electrical panels are sold on price, installed once, ignored for forty years, and judged successful when nothing happens. SPAN's choice was to ship one that does the opposite: monitor every circuit, run on its own software stack, talk to a phone, talk to a utility, and survive an outage with the lights on the things you care about.
The first SPAN Panel shipped in 2020. It cost more than a normal panel. People bought it anyway.
Four things in one grey rectangle.
SPAN Panel
A smart replacement for the main electrical panel. Circuit-level monitoring, app control, backup prioritization. Now in 16, 24 and 32-circuit flavors.
PowerUp EMS
The energy management software pre-loaded in every panel. First in the U.S. to clear UL 3141 - the standard the 2026 NEC will quietly require.
SPAN Drive
An EV charger that talks to the panel instead of fighting it. Dynamic speeds, time-of-use scheduling, no service upgrade required.
SPAN Edge
NEMA 3R outdoor device that gives utilities a programmable handle at the grid edge. PG&E's PanelBoost program runs on it.
SPAN is, technically, a hardware company. In practice it is a software company that ships its servers in a metal box bolted to a garage wall.
- Latitude Media, on the Series C roundHow the box got smart
// Milestones, in chronological order, with very little drama- 2018Arch Rao leaves Tesla. SPAN incorporates in San Francisco.
- 2020First SPAN Panel ships to homes. Series A closes.
- 2021Series B brings in Fifth Wall, Munich Re Ventures, Wellington.
- 2022Series B2: $96.5M. Headcount crosses 200.
- 2024SPAN Edge introduced. Utilities start paying attention.
- 2025UL 3141 PCS certification. 16 & 24-circuit panels launch.
- 2026Series C: $163M. PG&E PanelBoost rollout begins.
Money follows the breaker.
Climate hardware is not famously easy to finance. SPAN has, all the same, raised at every step of a brutal venture climate. The graph below is not meant to be triumphal - it is meant to show pacing.
SPAN funding by round
// Source: company disclosures, Crunchbase, Latitude MediaBars normalized against the Series C. Total disclosed funding to date: ~$426M.
Hardware is hard. Hardware sold through electricians is harder. Hardware sold through electricians AND utilities is the SPAN business plan.
- Anonymous climate VC, accuratelyMake electrification boring.
SPAN's own internal rallying cry is unromantic and useful: every American home, electrified, without ripping out the walls. The interesting part of that sentence is the last clause. A heat pump that requires a trench around the house is a heat pump that does not get installed. A solar plus battery system that needs a panel upgrade is a solar plus battery system that gets cancelled in week six. The point of the SPAN Panel is to remove the asterisk.
The grid-side argument is the same sentence in reverse. Utilities are watching peak demand rise as EVs and heat pumps land in their territory. Building more substations is slow and unpopular. A few thousand SPAN Edge devices, gently coordinating loads inside homes, is a substation in software. PG&E figured this out first. Others are listening.
The cheapest power plant.
Negawatts are cheaper than megawatts. The fastest way to handle a 4pm heat-pump-and-EV spike in 2030 is not a new gas peaker - it is software, distributed across millions of panels, dialing things down by ten percent for forty minutes. That is the world SPAN is quietly building toward. It is also the world the U.S. National Electrical Code is, as of 2026, beginning to assume.
If SPAN is right, the home electrical panel stops being a piece of utility plumbing and becomes a piece of consumer software - one with batteries, an app, a vendor relationship, and an upgrade path. If SPAN is wrong, somebody else will do it and cite them in the patent filings.
The grid is not running out of power. It is running out of coordination.
- a recurring point in Arch Rao's keynote slidesBack to the garage.
The Sacramento dryer finishes its cycle. The heat pump throttles back on its own. The Rivian, still in the driveway, has quietly resumed full charge - and the homeowner, eating dinner, has no idea any of this happened. The breaker box in the garage glows steady. The green dot on a planner's screen, somewhere in a PG&E office, stays green.
This is the part SPAN bet on. Not the gleaming app, not the touchscreen, not the press releases. The fact that on a perfectly ordinary Tuesday, in a perfectly ordinary house, something hard became invisible.
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