In a data center, the heat from a server is a problem to be solved with fans and chillers. In a swimming pool, it's a product you pay for. Hotta, a startup from Valencia, thinks it can be both at once.
The company, which rebranded from Therminer in 2024, builds what it calls modular computational boilers [Dealroom.co]. These are server racks designed not for an air-conditioned hall, but to be installed directly at a site with a high, constant demand for heat, like an industrial facility or a large aquatic center. The servers do their computing work, and the waste heat they produce is captured and piped into the site's heating system.
A wedge into the pool heater market
Hotta's most concrete move to date is a partnership with Fluidra, a global pool equipment giant based in Barcelona. In a press release last September, Fluidra highlighted Hotta's technology as a way to provide energy-efficient pool heating [Fluidra press]. For a startup with no other publicly disclosed customers, this is the clearest signal of its initial wedge. The logic is straightforward: pools need a lot of consistent, low-grade heat, and data centers produce a lot of waste heat. The company also cites blockchain, AI, and cloud computing as target sectors for its servers [Dealroom.co], but the Fluidra deal points to a pragmatic, near-term focus on thermal customers who already understand their heating bill.
The team and the early traction
Co-founders Gonzalo García Iranzo (CEO) and Aarón Molina Galán (CTO) launched the company in 2021. García Iranzo is listed in past roles at SAP and Molina Galán at CEMEX Ventures [RocketReach]. The team is small, reportedly around a dozen people [RocketReach][PitchBook]. Revenue is at an early stage, with one source citing approximately €500,000 annually [Onofre Gasent LinkedIn]. The company has been backed by the Valencia-based business incubator CEEI Valencia [CEEI Valencia].
The unit economics of warmth
The bet only works if the numbers pencil out twice: once for the heat buyer, and once for the compute buyer. For the facility manager, the math is about displacing gas or electric heating. A single high-performance server can dissipate over 500 watts of heat. A modest rack of 20 such servers represents a continuous 10 kilowatts of thermal energy. Over a year, that's about 87,600 kilowatt-hours of heat. In Spain, where industrial gas prices have fluctuated around €0.08 per kWh, that's roughly €7,000 worth of heat annually, per rack, that doesn't need to be purchased.
The other side of the ledger is trickier. Hotta must sell the computing power inside those servers at a rate that competes with large, efficient cloud providers. The value of the recovered heat becomes a discount it can offer, but it must still attract customers for its compute in a ferociously competitive market.
The competitive heat map
| Company | Base | Core Model |
|---|---|---|
| Hotta | Valencia, ES | Modular boilers for industrial heat (pools, facilities) |
| Heata | UK | Server heat for domestic hot water |
| Qarnot | France | Compute radiators for residential & office heating |
| Deep Green | UK | "Digital boilers" for public pools & leisure centers |
| Cloud&Heat | Germany | Liquid-cooled data centers for district heating |
The field splits along two axes: the temperature grade of the heat and the customer profile. Hotta, with its focus on pools and industry via the Fluidra link, is aiming for a commercial buyer with a predictable, year-round thermal load. Its key incumbent isn't another startup, but the gas boiler. To win, its total cost of ownership must undercut the cost of running a traditional data center plus a traditional boiler.