- NOX Energy raised €3M in seed funding to link home heat pumps to power markets.
- NOX says it has connected over 10,000 devices; rival Axle Energy claims 300,000.
- Rise PropTech and Volve Capital co-led the round, which follows a $1M raise in December 2024.
Before she started NOX Energy, Axelle Moortgat tested a platform that let Belgian households sell surplus solar power to their neighbours. Energy suppliers, which pay penalties when their portfolios fall out of balance, did not like it, she toldForbes Belgium. Her next idea worked with suppliers instead, and it has raised €3 million in seed funding.
NOX Energy was founded by Moortgat, 26, CEO, Louis Clermont, 24, COO, and Martin Michaux. It sells software that lets heat pumps and solar panels respond to electricity prices.
The round was co-led by Rise PropTech and Volve Capital, with Seeder Fund, Uneti Ventures, Fair Capital Impact Fund, and 100in also investing. NOX says it has connected more than 10,000 devices and counts Eneco and Frank Energie among its customers. The round makes it a fully European company, and the team has grown to 13 people.
“Every time money moves between two banks, it runs over SWIFT. We want to be that for energy flexibility. Millions of homes already have a heat pump, battery or solar panels connected to their manufacturer’s app. Energy suppliers and grid operators need the flexibility these devices can offer, but every manufacturer and every market works differently. NOX sits in between as the infrastructure of flex, connecting both sides. Our goal is for every kilowatt-hour of flexibility in Europe to run through NOX,” said Moortgat.
A neutral layer between heat pumps and the grid
Wind and solar produced 30% of EU electricity in 2025, overtaking fossil fuels (29%) for the first time, according to think tank Ember. Supply is harder to predict, and someone has to absorb the swings. Homes can do part of that. A heat pump can pre-heat a house when power is cheap and wait when it is scarce, without the household noticing.
The startup, founded in 2024, works by connecting its software to a heat pump through the app of the manufacturer or energy supplier, then deciding when the device runs. When prices are low, it lets the pump run harder and pre-heats the home. It also forecasts the pump’s consumption for the next 24 hours.
Grid operators pay for that flexibility, and NOX passes part of the revenue to manufacturers and households. Its website promises households savings of up to 28% and earnings of up to €200 a year, with no extra hardware.
Its live integrations cover heat pumps and solar panels. They include DeWarmte, NextEnergy, Frank Energie’s smart heating and solar steering, and the NIBE Group brands through myUplink.
NOX began as a Belgian-American startup and went through the Entrepreneurs Roundtable Accelerator in New York. It raised about $1 million in December 2024 from Volve Capital, Seeder, and angel investors. The new round brings disclosed funding to close to €4 million, by TFN’s calculation. In a December 2024 interview with Flanders’ innovation agency VLAIO, the company said it wanted to be worth €100 million within five years.
Rivals with more devices and more money
Tech Funding News covered London’s Axle Energy when it raised a $1.6 million pre-seed in June 2023 and a £7 million seed in August 2024. It has since closed a $25 million Series A led by Energize Capital and says it manages more than 300,000 devices, representing over two gigawatts of flexible capacity. That is 30 times NOX’s reported device count.
In Germany, 1KOMMA5° extended its €150 million pre-IPO round in July 2025 and plans to invest more than €100 million in software between 2025 and 2027. Its Heartbeat AI virtual power plant reportedly controls more than 500 megawatts.
Berlin’s Nomos raised €20 million from Index Ventures in September 2026 to connect home batteries, electric vehicles and heat pumps to Germany’s power market as a licensed supplier behind installers’ brands. NOX takes the opposite route and stays inside its partners’ apps.
Closer to home, Antwerp’s LIFEPOWR raised €5.65 million in November 2025 and manages more than 22,000 connected assets. Belgian Companion.energy closed a €7.8 million seed round in June 2026, though it serves industrial customers.
Axle also sells to suppliers and manufacturers through software interfaces, so NOX’s clearest difference is focus rather than model: heat pumps and supplier apps in Belgium and the Netherlands. That is an advantage if heat pumps become the biggest source of household flexibility, and a limit if they do not.
Where the €3 million goes
The money will fund expansion beyond Belgium and the Netherlands, and the work of building NOX’s optimisation directly into manufacturers’ and suppliers’ existing apps.
The SWIFT comparison cuts both ways. SWIFT works because banks agreed on one standard. NOX needs the same agreement from heat pump makers and suppliers, who can also choose Axle or 1KOMMA5°, or build their own. With about 10,000 devices and 13 people, the question is whether a neutral layer can win before the bigger players make that layer their own.
