The hardest part of decarbonizing a factory is often the heat. Not the ambient warmth, but the searing, 400-plus-degree Celsius process heat used to dry paper, cure chemicals, or sterilize food. For decades, that heat has come almost exclusively from burning gas or coal. A French startup called Airthium is now shipping a machine, in a container, that it says can deliver that same blistering heat from electricity alone.
Founded in 2016 by plasma physicist Andreï Klochko and operator Franck Lahaye, Airthium has spent eight years developing what it calls a "new kind of industrial heat pump" [Perplexity Sonar Pro Brief]. The core innovation is a reversible Stirling-cycle engine that can pump heat to an industry-first 550°C (1,022°F). The system is designed as a drop-in unit, meant to sit alongside a factory's existing gas boiler and take over whenever grid electricity is cheap and clean [Perplexity Sonar Pro Brief]. The company's recent $3.25 million Series A, led by Daphni with Eren Groupe and Polytechnique Ventures, is a bet that this high-temperature wedge can crack open the $13 billion annual market for industrial process heat [Nordic9.com, Feb 2024][Facebook/Airthium, 2023].
The physics of a hot swap
Airthium's technology is a deep hardware play. It uses helium or nitrogen as a working fluid in a closed-loop Stirling engine, compressing and expanding the gas in a near-isothermal process that approximates an Ericsson cycle for high efficiency [heatpumpingtechnologies.org, 2026]. This allows it to achieve a temperature "lift" of 200°C in a single stage, far beyond conventional heat pumps. Crucially, the engine is fully reversible. In one mode, it acts as a heat pump, using electricity to produce high-grade heat. Flip it, and it becomes a heat engine, converting stored heat back into electricity [Airthium].
This reversibility unlocks a second, potentially larger, business: long-duration energy storage. The company envisions using its machines to convert excess renewable electricity into heat, stored in molten salt at around 540°C, and then back into power when needed. It claims a round-trip efficiency near 70% at a storage cost of around $110 per kilowatt-hour [Perplexity Sonar Pro Brief].
A plug-and-play wedge for heavy industry
The initial go-to-market strategy is pragmatic. Airthium isn't selling a greenfield factory overhaul. It's selling a containerized heat source that plugs into a plant's existing steam network or thermal oil system [heatpumpingtechnologies.org, 2026]. The value proposition is operational savings: run the electric heat pump when power prices are low, and fall back on the legacy gas boiler during peaks.
The target customers are in industries where medium- to high-temperature heat is a core cost center: food processing, paper manufacturing, automotive, and mining [Perplexity Sonar Pro Brief].
The team and the traction
CEO and CTO Andreï Klochko holds a PhD in Plasma Physics from École Polytechnique and built the first Airthium prototype single-handedly [TheOrg, 2026]. COO Franck Lahaye handles commercial and operational strategy. The $3.37 million in total disclosed funding is modest for hardware development [TheCompanyCheck, 2024].
Airthium has a customer-story partnership with Dassault Systèmes, which highlights the use of its simulation tools in developing the heat pump [Dassault Systèmes, Feb 2023]. Financials show the company is in the investment phase, with 2023 revenue of $374,300 against a net loss of $1.2 million [Owntric, 2026].
| Round | Date | Amount | Lead Investor(s) |
|---|---|---|---|
| Seed | Mar 2021 | $120,000 | Y Combinator [Tracxn] |
| Crowdfunding | Mar 2021 | $1,070,000 | [Kingscrowd, 2021] |
| Series A | Mar 2024 | $3,250,000 | Daphni, Eren Groupe, Polytechnique Ventures [Nordic9.com, Feb 2024] |
Where the wheels could come off
Airthium faces the standard gauntlet of a capital-intensive hardware startup moving from lab to field. The technology is still "under demonstration" at its laboratory [heatpumpingtechnologies.org, 2026]. The leap to reliable, multi-megawatt units operating in harsh industrial environments is non-trivial. Competition exists, notably from established players like Mayakawa and specialists like Sustainable Process Heat (SPH).
The next twelve months
The key milestone for Airthium is getting the first non-lab unit humming at a customer site. The next round of funding, likely a Series B, will be priced on the data from that deployment, uptime, efficiency in the wild, and the customer's actual savings.
On paper, the unit economics are tantalizing. Consider a mid-sized factory using 1 MW of thermal energy, eight hours a day. At a European industrial gas price of around €30 per MWh, the daily fuel cost is about €240. If Airthium's heat pump can run when electricity is below, say, €50 per MWh, and achieves a coefficient of performance (COP) of 3, the daily cost drops to roughly €133. That's a 45% saving on energy, before counting carbon credits or avoided grid fees.