NOX Energy Raises €3M Seed To Expand Energy Software Across Europe

NOX Energy, the Belgian-American startup connecting home heat pumps to electricity markets, has raised €3 million in seed funding co-led by Rise PropTech and Volve Capital. The round included participation from Seeder Fund, Uneti Ventures, Fair Capital Impact Fund, and 100in .

The funding follows a $1 million pre-seed round in December 2024 and brings NOX’s total disclosed funding to approximately €4 million. The company has connected over 10,000 devices and counts Eneco and Frank Energie among its customers .

NOX Energy Financials By CREDX Media

Startup	NOX Energy
Founders	Axelle Moortgat, Louis Clermont, Martin Michaux
Founded	2024
Headquarters	Antwerp, Belgium
Latest Round (Seed)	€3M
Previous Round (Pre-Seed, December 2024)	€1M
Total Funding Raised	~€4M
Lead Investors	Rise PropTech, Volve Capital
Key Investors	Seeder Fund, Uneti Ventures, Fair Capital Impact Fund, 100in
Employees	13
Business Model	Software platform connecting heat pumps to energy markets
Category	Energy Tech, Virtual Power Plants, Grid Flexibility
Connected Devices	10,000+
Customers	Eneco, Frank Energie

Startup Overview: NOX Energy

What NOX Energy Is Building in Simple Words

NOX Energy builds software that connects home heat pumps to electricity markets, turning them into grid-balancing assets. The company’s platform sits between heat pump manufacturers and energy suppliers, allowing homes to earn money by adjusting when their heating runs.

• Heat Pump Optimization: When electricity prices are low, NOX lets the heat pump run harder and pre-heats the home. When prices spike, it pauses. The household never notices—but the grid does
• 24-Hour Forecasting: NOX predicts the heat pump’s consumption for the next day, helping energy suppliers buy more accurately and reduce balancing costs
• No New Hardware: The software connects through the manufacturer’s or supplier’s existing app—no installer visit required
• Customer Traction: Eneco’s pilot with NOX customers saw average savings of €29 per month—€16 from consumption optimization and €13 from flexibility rewards
• The SWIFT Analogy: CEO Axelle Moortgat describes NOX as the infrastructure layer for energy flexibility: “Every time money moves between two banks, it runs over SWIFT. We want to be that for energy flexibility”

Why NOX Energy Matters

1. Renewables Created a Balancing Problem Wind and solar produced 30% of EU electricity in 2025, overtaking fossil fuels for the first time. Supply is harder to predict, and someone has to absorb the swings. Homes can do part of that .
2. Heat Pumps Are Everywhere—And Flexible Europe had approximately 25 million heat pumps in 2024, with the EU targeting 40 million by 2030. Each one is a thermal battery that can shift consumption by hours without affecting comfort .
3. Suppliers Pay for Imbalance Energy suppliers face penalties when their portfolios fall out of balance. NOX solves this by forecasting and controlling heat pump demand, reducing costs for suppliers while paying homeowners .
4. Market Is Growing Fast Europe’s residential VPP market connected 3.3 million DERs by end-2025, with smart heating as the largest category. That number is forecast to grow at 18.1% CAGR through 2030 .

Startup Story: From Energy Sharing Failure to Grid Balancing Success

NOX Energy didn’t start with heat pumps. It started with a failed idea.

Before founding NOX, CEO Axelle Moortgat built a platform that let Belgian households sell surplus solar power to their neighbours. The concept was elegant: match producers and consumers directly, take a commission. There was just one problem—energy suppliers hated it.

Suppliers pay penalties when their portfolios fall out of balance. If customers bought and sold energy “behind their backs,” balancing became nearly impossible, and suppliers lost margins paying fines. “They were losing money,” Moortgat told Forbes Belgium .

So she asked them a different question: “Is there nothing we can do together?” The answer revealed the real problem. Solar and wind growth was making grid balancing harder every year. Suppliers needed help managing volatility.

Moortgat knew a heat pump manufacturer. She proposed an idea: what if heat pumps could be controlled intelligently to solve the balancing problem? The manufacturer agreed to a pilot. She found co-founders through Y Combinator’s Co-Founder Matching Platform—Louis Clermont (COO) and Martin Michaux (CTO)—and NOX was born .

Within two months, the team was selected for the Entrepreneurs Roundtable Accelerator in New York, moved there for four months, and raised their first $150,000. They returned to Europe with pilots underway at major manufacturers and a clear thesis: own the flexibility layer for heat pumps .

Founder Background: Belgium’s 30 Under 30 Building Grid Infrastructure

Axelle Moortgat (CEO) is a computer science engineer who previously worked at Robovision and the startup Credix. She was named to Forbes Belgium’s 30 Under 30 list alongside her co-founders .

Louis Clermont (COO) brings business and finance expertise. Martin Michaux (CTO) leads data science and AI engineering. The three founders represent Belgium’s three regions—Flanders, Brussels, and Wallonia—and met just nine months before founding the company .

Their ambition is explicit. In a December 2024 interview with Flanders’ innovation agency VLAIO, NOX stated it wants to be worth €100 million within five years. If achieved, Moortgat would be Belgium’s first female CEO of a unicorn .

The Energy Flexibility Race Nobody Expected

NOX operates in an increasingly crowded field. The competition falls into three camps:

Device-Heavy Incumbents: Axle Energy raised a $25 million Series A led by Energize Capital and manages over 300,000 devices—30 times NOX’s count . Nomos raised €20 million from Index Ventures in September 2026 and serves as a licensed supplier behind installers’ brands .

Regional Players: Antwerp’s LIFEPOWR raised €5.65 million and manages 22,000 connected assets. Belgian Companion.energy closed a €7.8 million seed round but focuses on industrial customers .

NOX’s Differentiation: Rather than competing on device count or becoming a licensed supplier, NOX stays inside its partners’ apps. It focuses specifically on heat pumps—the largest residential DER category in Europe—and operates in Belgium and the Netherlands, where heat pump adoption is accelerating .

“NOX’s clearest difference is focus rather than model,” TFN noted. “That is an advantage if heat pumps become the biggest source of household flexibility, and a limit if they do not” .

Founder Intelligence: What Founders Can Learn from NOX

• Listen to incumbents, not just customers: Moortgat’s first idea failed because suppliers opposed it. She pivoted by asking what they actually needed—and built that instead.
• Solve the expensive problem: Suppliers pay penalties for imbalance. NOX reduces those penalties. The value proposition is measurable and urgent.
• Focus beats scale: Axle has 30x more devices but spreads across multiple asset types. NOX owns heat pumps in two markets deeply before expanding.
• Speed compounds: Two months from founding to New York accelerator. Fourteen months from launch to €3M seed. Momentum attracts investors.

Investor Intelligence: Why This Round Gets Premium Capital

Rise PropTech brings real estate and built environment expertise—relevant as heat pumps become standard in European homes. Volve Capital, which led the pre-seed, returned for the seed, signaling continued conviction .

Seeder Fund and Uneti Ventures provide early-stage European tech experience. Fair Capital Impact Fund and 100in bring impact and regional network depth .

The round makes NOX “a fully European company,” per TFN—moving beyond its Belgian-American origins to target Northern European expansion .

The Road Ahead for NOX Energy

Expansion Targets

With €3 million in capital, NOX will:

• Expand beyond Belgium and the Netherlands into Northern Europe
• Build optimization directly into manufacturer and supplier apps
• Grow the team beyond its current 13 people
• Target additional heat pump manufacturers for integration

Competitive Response

Expect:

• Axle Energy and Nomos to deepen heat pump integrations
• Traditional VPP platforms to acquire or build heat pump capabilities
• New startups targeting specific residential DER categories
• NOX’s moat: heat pump focus + supplier-app distribution + Belgian/Dutch market depth

Conclusion

NOX Energy’s €3 million seed round validates the thesis that heat pumps are the most underappreciated source of residential grid flexibility in Europe. The company’s approach—embedding software inside existing supplier apps rather than building a standalone platform—reduces adoption friction and aligns with how energy suppliers actually operate.

Market tailwinds favor NOX: 25 million heat pumps in Europe, an 18% CAGR in residential VPP connections, and suppliers desperate for balancing solutions. The company’s focus on heat pumps and supplier relationships positions it to capture this opportunity—provided it can scale device count before better-funded rivals close the gap.

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Frequently Asked Questions

1. What is NOX Energy’s total funding and latest round size?
NOX Energy has raised approximately €4 million total across two rounds. Its €3 million seed round was co-led by Rise PropTech and Volve Capital in September 2026.

2. How much did NOX Energy raise in its seed round and who led the investment?
NOX Energy raised €3 million in seed funding co-led by Rise PropTech and Volve Capital, with participation from Seeder Fund, Uneti Ventures, Fair Capital Impact Fund, and 100in.

3. What was NOX Energy’s pre-seed round size?
NOX Energy raised $1 million in December 2024 from Volve Capital, Seeder Fund, and angel investors, bringing total disclosed funding to approximately €4 million.

4. What is the valuation of NOX Energy?
NOX Energy’s post-money valuation has not been publicly disclosed. The company stated in December 2024 that it aims to be worth €100 million within five years.

5. Who are the major investors in NOX Energy?
Major investors include Rise PropTech and Volve Capital (seed co-leads), Seeder Fund, Uneti Ventures, Fair Capital Impact Fund, and 100in.

6. How many devices has NOX Energy connected?
NOX Energy has connected over 10,000 devices, including heat pumps and solar panels, with customers including Eneco and Frank Energie.

7. Who are NOX Energy’s founders?
NOX Energy was founded in 2024 by Axelle Moortgat (CEO), Louis Clermont (COO), and Martin Michaux (CTO), all named to Forbes Belgium’s 30 Under 30 list.

8. What is NOX Energy’s business model?
NOX Energy operates a software platform that connects heat pumps to energy markets, earning fees from energy suppliers and grid operators for balancing services while sharing savings with homeowners.

9. How does NOX Energy’s technology work for heat pumps?
NOX connects to heat pumps through manufacturer or supplier apps, then optimizes when devices run based on electricity prices, forecasts consumption for 24 hours, and earns flexibility rewards for grid balancing.

10. What is the SWIFT analogy for NOX Energy?
CEO Axelle Moortgat describes NOX as the SWIFT of energy flexibility—infrastructure that sits between heat pumps and energy markets, enabling every kilowatt-hour of flexibility to flow through its platform.

11. How much can NOX Energy customers save?
Eneco’s pilot with NOX showed average customer savings of €29 per month—€16 from consumption optimization and €13 from flexibility rewards, totaling over €300 per year.