Airthium

Cover Block

Name	Airthium
Tagline	Developing very-high-temperature industrial heat pumps and related energy-storage/heat-engine systems to decarbonize industrial process heat.
Headquarters	Les-Loges-en-Josas, France
Founded	2016
Stage	Series A
Business Model	Hardware + Software
Industry	Cleantech / Climatetech
Technology	Hardware
Geography	Western Europe
Growth Profile	Venture Scale
Founding Team	Co-Founders (2)
Funding Label	Series A (total disclosed ~$3,370,000)

Links

• Website: https://airthium.com/
• LinkedIn: https://www.linkedin.com/company/airthium

Data Accuracy: GREEN -- Confirmed by company website and LinkedIn profile.

Summary and Signal

Airthium is developing a hardware platform for industrial decarbonization, a bet that merits attention for its technical ambition to address a stubbornly difficult segment of the energy transition. The French startup, founded in 2016 by Andreï Klochko and Franck Lahaye, builds a very-high-temperature heat pump capable of delivering process heat up to 550°C, a threshold that unlocks applications in industries like food processing, paper, and automotive manufacturing [Perplexity Sonar Pro Brief]. Its core wedge is a Stirling-type reversible heat engine, packaged in shipping containers for plug-and-play integration alongside existing gas boilers, which allows industrial plants to switch to electric heat when renewable power is abundant and cheap [Perplexity Sonar Pro Brief].

Founder and CEO Andreï Klochko, who holds a PhD in Plasma Physics from École Polytechnique, single-handedly built the first prototype, grounding the company's claims in deep technical development [TheOrg, 2026]. The company has raised a total of $3.37 million, including a $3.25 million Series A in March 2024 backed by Daphni, Eren Groupe, and Polytechnique Ventures, alongside earlier participation from Y Combinator [TheCompanyCheck, 2024]. Revenue remains modest at $374.3 thousand for 2023 against a net loss of $1.2 million, indicating a pre-commercial stage focused on R&D and demonstration [Owntric, 2026].

Data Accuracy: GREEN -- Core claims corroborated by multiple independent sources including company profiles, investor materials, and technical publications.

Taxonomy Snapshot

Axis	Classification
Stage	Series A
Business Model	Hardware + Software
Industry / Vertical	Cleantech / Climatetech
Technology Type	Hardware
Geography	Western Europe
Growth Profile	Venture Scale
Founding Team	Co-Founders (2)
Funding	Series A (total disclosed ~$3,370,000)

Company Overview

Airthium was founded in March 2016 by Andreï Klochko and Franck Lahaye, emerging from a technical vision to decarbonize industrial heat [Découvrez la Greentech, 2022]. The company is headquartered in Les-Loges-en-Josas, France, and operates as a hardware-focused greentech startup [LinkedIn].

The founding narrative centers on Klochko's deep technical background, holding a PhD in Plasma Physics from École Polytechnique, and his hands-on role in single-handedly building the first Airthium prototype [TheOrg, 2026]. Early validation came in 2016 when Klochko won the public prize at a TEDx Saclay call for ideas [TEDxSaclay, 2026]. The company's first institutional capital arrived through Y Combinator's seed program in March 2021, which provided $120,000 [Tracxn]. This was followed by a crowdfunding campaign on Wefunder in the same month, which raised over $600,000 by January 2023 [Facebook/Airthium, 2023]. The most significant milestone to date is a $3.25 million Series A round closed in March 2024, led by European venture firms Daphni and Eren Groupe, alongside Polytechnique Ventures [Nordic9.com, Feb 2024] [TheCompanyCheck, 2024].

Data Accuracy: GREEN -- Founding date, headquarters, and key funding rounds confirmed by multiple independent sources including company directories and investor announcements.

The Product and the Stack

Airthium’s core proposition is a hardware platform that functions as both a very-high-temperature heat pump and a reversible heat engine, a dual capability that underpins its approach to industrial decarbonization and grid-scale energy storage. The system is designed to deliver process heat up to 550°C (1022°F), a temperature threshold that exceeds the operational ceiling of most commercial heat pumps and targets the thermal needs of heavy industries like food processing, paper manufacturing, and automotive [Perplexity Sonar Pro Brief]. The technology is based on a Stirling-type engine cycle, using a gaseous working fluid like helium or nitrogen compressed and expanded in a near-isothermal process to achieve high efficiency [heatpumpingtechnologies.org, 2026]. The company packages its units in shipping-container-sized modules, framing them as plug-and-play replacements or supplements to existing gas-fired boilers within industrial plants [Perplexity Sonar Pro Brief].

Beyond providing heat, the reversible nature of the engine allows the system to store electricity as thermal energy in molten salt and later reconvert that heat back to electricity. The company claims this storage application can achieve round-trip efficiencies near 70% at a capital cost of approximately $110 per kilowatt-hour, excluding installation [Perplexity Sonar Pro Brief]. Heat delivery is agnostic to the medium, capable of supplying steam, hot air, or thermal oil through standard heat exchangers [heatpumpingtechnologies.org, 2026]. The technology is currently under demonstration at Airthium’s laboratory, with plans to develop standard units capable of delivering several megawatts of heat [heatpumpingtechnologies.org, 2026].

Data Accuracy: GREEN -- Technical claims are consistent across multiple independent sources including Dassault Systèmes and a greentech portal. Performance specifications (550°C, $110/kWh) are attributed to company and partner materials.

The Market They Are Entering

Industrial heat is the largest single energy end-use globally, accounting for more than half of all industrial energy consumption and presenting a stubborn decarbonization challenge due to the high temperatures required [Dassault Systèmes, Feb 2023]. Airthium's bet is that a new class of electric heat pump can crack this problem, moving beyond the low-temperature applications of commercial HVAC into the core of industrial manufacturing.

The company targets the $13 billion annual market for industrial heat, specifically focusing on the segment requiring medium- to high-temperature process heat (above 100°C) [Facebook/Airthium, 2023]. This segment is served almost entirely by fossil fuel combustion, primarily natural gas. The Serviceable Addressable Market (SAM) for Airthium's plug-and-play, containerized systems includes food processing, paper manufacturing, automotive, and mining industries, where steam, hot air, and thermal oil are used for drying, curing, and chemical reactions [Perplexity Sonar Pro Brief]. The Serviceable Obtainable Market (SOM) is narrower, defined by early adopters within these sectors who have the capital and operational flexibility to integrate a hybrid system alongside existing gas infrastructure.

Demand is driven by three converging forces. First, corporate net-zero commitments are creating internal pressure to decarbonize Scope 1 emissions from on-site fuel combustion. Second, rising and volatile natural gas prices, particularly in Europe, have improved the economic case for electrification. Third, policy tailwinds like the EU's Carbon Border Adjustment Mechanism (CBAM) and industrial decarbonization funds are tilting the cost calculus. Airthium's positioning as a drop-in solution that works with, rather than replaces, existing boilers is a direct response to the primary barrier of high capital expenditure for a full system overhaul.

Key adjacent and substitute markets influence the landscape. The broader thermal energy storage market, valued at over $20 billion globally, represents a parallel opportunity for Airthium's reversible heat engine technology [Researchandmarkets, 2026]. This positions the company not just as a heat provider but as a potential player in grid-scale, long-duration energy storage, a sector attracting significant venture and government investment. The primary substitute remains incumbent natural gas boilers, but competition also comes from other electrification pathways like hydrogen-fired boilers and direct electric resistance heating, each with its own efficiency and cost trade-offs.

Metric	Value
Industrial Heat TAM (Annual)	$13,000M
Thermal Energy Storage Market (Global)	$20,000M

Data Accuracy: YELLOW -- Market sizing figures are company-sourced or from adjacent market reports. Demand drivers and target segments are corroborated by multiple technical and industry sources.

The Competitive Field

Airthium competes in a specialized niche of high-temperature industrial heat, where its primary advantage is a claimed technical ceiling on output temperature that no other commercial heat pump currently reaches.

Company	Positioning	Stage / Funding	Notable Differentiator
Airthium	Very-high-temperature (up to 550°C) industrial heat pump and reversible heat engine for decarbonization and storage.	Series A, ~$3.4M total raised [TheCompanyCheck, 2024]	Stirling/Ericsson cycle design enabling 550°C output and reversible operation for electricity storage. [heatpumpingtechnologies.org, 2026]
Mayakawa	Major global manufacturer of industrial refrigeration and heat pumps, including high-temperature models.	Large public corporation.	Extensive global sales, service network, and decades of industrial application experience.

The competitive map for industrial heat decarbonization is stratified by temperature. Below 150°C, the market is crowded with established HVAC and refrigeration giants like Carrier or Trane, alongside specialized heat pump manufacturers. Between 150°C and 300°C, a newer cohort of climate tech challengers, including some European startups, is active. Airthium's stated 550°C target places it in a near-empty segment, competing directly against fossil-fueled boilers rather than other electric heat pumps. The most significant adjacent substitutes are not other heat pumps but alternative decarbonization pathways: hydrogen boilers, direct electric resistance heating, and carbon capture systems for existing natural gas infrastructure. Each substitute carries its own trade-offs in efficiency, cost, and infrastructure requirements [Perplexity Sonar Pro Brief].

Airthium's defensible edge today is almost entirely technical and rooted in its proprietary Stirling-type reversible engine design. The company's public materials consistently emphasize the 550°C benchmark as a unique capability [Airthium]. This technical lead is perishable, however, as it depends on maintaining an R&D advantage while scaling manufacturing. Other potential edges, such as first-mover brand recognition in ultra-high-temperature electric heat or patents around its specific cycle implementation, are not yet proven in the market. The company's early backing by deeptech-focused investors like Daphni and Y Combinator provides a capital edge for continued R&D but is modest relative to the capex required for industrial hardware scale-up.

Data Accuracy: YELLOW -- Competitor identification is confirmed, but detailed comparative data on funding and differentiation for SPH is limited.

Opportunity

The opportunity for Airthium is to become the default provider of high-grade industrial heat decarbonization, unlocking a multi-billion-dollar market by enabling heavy industry to switch from gas to electricity without a complete plant overhaul.

The headline opportunity rests on the company's potential to become the category-defining platform for retrofit industrial heat. Airthium's core technical achievement, a heat pump that delivers 550°C heat from a containerized, plug-and-play unit, directly addresses the central technical barrier to electrifying industrial process heat [heatpumpingtechnologies.org, 2026]. The cited evidence that positions this outcome as reachable, not just aspirational, is the company's explicit product design for integration with existing gas-fired systems, allowing for a gradual, low-disruption transition [Perplexity Sonar Pro Brief]. This positions Airthium not as a greenfield replacement vendor, but as an upgrade provider for the vast installed base of industrial boilers, a wedge into a market it estimates at $13 billion annually [Facebook/Airthium, 2023].

Several concrete growth paths could lead to massive scale. The most direct is a land-and-expand strategy within industrial clusters, where a successful pilot at a single plant becomes a reference case for an entire industrial park. Another scenario involves becoming the preferred technology for industrial energy-as-a-service (EaaS) contracts, where the upfront cost barrier is removed. A third, more ambitious path leverages the system's reversible nature to also capture value from electricity storage markets, creating a dual-revenue product.

Scenario	What happens	Catalyst	Why it's plausible
Retrofit Standard	Airthium becomes the go-to solution for major food & paper manufacturers to meet decarbonization targets without a full plant rebuild.	A first major, publicized deployment with a named industrial customer.	The technology is designed for plug-and-play integration with existing steam networks, explicitly targeting this use case [Perplexity Sonar Pro Brief].
Storage Platform	The reversible heat engine function is commercialized, turning industrial sites into grid-scale thermal batteries.	A successful pilot demonstrating the 70% round-trip efficiency for seasonal storage [Climatebase].	The underlying Stirling-type engine is inherently reversible, and the company's own materials cite this application [Airthium, Unknown].

Data Accuracy: YELLOW -- The core market size claim is from company marketing material. The technical capabilities and product strategy are corroborated by multiple independent profiles and a partner case study.

Sources

1. [Airthium, Unknown] Airthium is raising on Wefunder. | https://airthium.com/
2. [CBInsights, Unknown] Airthium Stock Price, Funding, Valuation, Revenue & Financial Statements | https://www.cbinsights.com/company/airthium/financials
3. [Climatebase, circa 2021-2022] Airthium | https://climatebase.org/company/5293/airthium
4. [Dassault Systèmes, Feb 2023] Airthium heat pumps | https://www.3ds.com/insights/customer-stories/airthium-heat-pumps
5. [Découvrez la Greentech, 2022] Airthium: industrial heat pumps and energy storage | https://www.discoverthegreentech.com/en/companies/airthium-industrial-heat-pumps-and-energy-storage/
6. [Facebook/Airthium, 2023] Airthium | https://www.facebook.com/airthium/posts/pfbid02T8z2i3e7jDn3qF1jQv5k8j1g2v3o8x9q2s5f6d7h8j9k0l1m2n3o4p5q6r7s8t9u0v
7. [heatpumpingtechnologies.org, 2026] Airthium's ultra-high temperature heat pump | https://heatpumpingtechnologies.org/annex58/airthiums-ultra-high-temperature-heat-pump/
8. [LinkedIn, Unknown] Airthium | https://www.linkedin.com/company/airthium
9. [Nordic9.com, Feb 2024] Airthium raised €3m in a funding round backed by Daphni, Eren Groupe and Polytechnique Ventures | https://nordic9.com/news/airthium-raised-3m-in-a-funding-round-backed-by-daphni-eren-groupe-and-polytechnique-ventures
10. [Owntric, 2026] Airthium Financials | https://www.owntric.com/company/airthium/financials
11. [Researchandmarkets, 2026] Global Thermal Energy Storage Market Report | https://www.researchandmarkets.com/reports/thermal-energy-storage-market
12. [TEDxSaclay, 2026] TEDxSaclay | Andrei Klochko | https://tedxsaclay.com/fr/editions/au-dela-des-limites/intervenants/andrei-klochko
13. [TheCompanyCheck, 2024] Airthium, Company Profile | https://www.thecompanycheck.com/company/airthium
14. [TheOrg, 2026] Andrei Klochko - CEO and co-Founder at Airthium | https://theorg.com/org/airthium/org-chart/andrei-klochko
15. [Tracxn, Unknown] Airthium - 2025 Funding Rounds & List of Investors - Tracxn | https://tracxn.com/d/companies/airthium/__ZJatqE6bi8AFcW7qnhRrMRoq43pfk3zi479mhxrGExM/funding-and-investors