WHAT WE DO
From potential to operational heat recovery
FOR DATA CENTRES OPERATORS
Recover your data centre's waste heat. No investment required.
EU regulation requires waste heat recovery assessment for data centres above 1 MW. Calentix designs, installs and operates waste heat recovery systems in data centres across Europe — and delivers the captured heat to local district heating networks under a long-term Heat Purchase Agreement. You contribute the heat. We do everything else.
WHY THIS IS IMPORTANT FOR DATA CENTRES
What does EU regulation mean for your data centre?
The European Union's first formal assessment of data centre energy performance (2023 data, ~748 reporting facilities) found that the weighted average Energy Reuse Factor (ERF) across all data centres is just 1.9%. Among the roughly 50 operators that do recover waste heat, the average ERF rises to 23.5%.
The gap between those who act and those who don't is closing — not because operators are choosing to, but because legislation is forcing the issue.
Under the EU Energy Efficiency Directive (EED) and its associated Delegated Regulation 2024/1364, data centres above 500 kW IT load are already required to report their ERF annually. Minimum Performance Standards (MPS) — including mandatory ERF thresholds — are under active development and expected to take effect within the next few years. Germany's Energieeffizienzgesetz (EnEfG) already requires data centres to make waste heat available and register on the national Abwärmeplattform.
The question is not whether your data centre will need to address waste heat. It's whether you'll be ready.
CALENTIX IS A HEAT PRODUCER BASED ON RECOVERED HEAT FROM DATA CENTRES
Calentix is a heat producer. The fuel is your waste heat.
Most data centres generate enormous amounts of heat as a by-product of cooling — and reject it into the atmosphere. Calentix captures that heat, upgrades it using industrial heat pumps, and sells it to a district heating network as usable energy. For your data centre, this means one thing: your cooling load becomes a clean energy source — without you having to produce, sell or manage anything. Here is how Calentix makes that happen, from first conversation to long-term operation.
-
Feasibility — Calentix assesses your facility's thermal output, cooling configuration and proximity to district heating infrastructure. This takes 4–8 weeks and requires access to your IT load profiles and cooling system temperature data.
-
Design and permitting — We design the heat extraction system (heat exchangers, heat pumps, pipework) and manage all permitting and planning.
-
Installation — Our modular, containerised equipment is installed with minimal disruption to your operations. The system interfaces with your existing cooling infrastructure.
-
Operation — Calentix operates and maintains the system under a long-term Heat Purchase Agreement (HPA) with the district heating operator. You have no ongoing operational obligations.
-
ERF reporting — We provide all metered energy data required for your annual ERF reporting under EU EED and national regulations.
Calentix owns the equipment throughout the contract period. You retain full control of your data centre operations.
What data centre operators gain from a Calentix partnership
BENEFITS FOR DATA CENTRE OPERATORS
Zero capital investment
The heat extraction system — heat pumps, heat exchangers, pipework, controls — is financed, installed and owned by Calentix. There is no capex requirement and no balance-sheet impact for the data centre operator.
ERF compliance without internal expertise
Calentix provides fully metered, auditable energy data for your annual ERF submissions under EU EED and national regulations. We also support your reporting to national waste heat registers and platforms.
No operational complexity
You do not need heat engineering expertise in-house. Calentix operates the system, handles maintenance and manages the commercial relationship with the district heating operator.
ESG and sustainability credentials
Recovered heat displaces fossil-fuel-generated heat in district heating networks, directly reducing your Scope 1 and Scope 3 carbon footprint.
Long-term certainty
The Heat Purchase Agreement between Calentix and the district heating operator runs for 15–25 years, giving all parties long-term visibility. The structure is bankable and designed to withstand changes in energy markets and regulatory frameworks.
No interference with data centre operations
The heat extraction system is physically separated from your IT equipment and cooling infrastructure. System design ensures your cooling performance and uptime commitments are not affected.
WHAT WE OFFER
Five things we handle
so you don't have to
Full notification package and waste heat utilisation plan — audit-ready, regulator-facing documents formatted for BfEE and EED submission.
EED & EnEfG compliance documentation
Data centres contributing heat are viewed as community assets by municipalities — significantly strengthening planning positions and licence-to-operate arguments in dense urban locations.
Community value & planning support
Heat reuse reduces cooling electricity demand by 10–15%, directly improving your Power Usage Effectiveness (PUE) metrics — relevant for both EnEfG PUE ≤1.2 target and sustainability reporting.
Reduced cooling costs & improved PUE
Every MWh of recovered heat replaces fossil combustion in district heating. Calentix provides verified documentation for your ESG and Scope 3 reporting.
Verified carbon reduction
Calentix finances, builds and owns the heat-recovery system. You sign a Heat Access Agreement (HAA) — zero capex, zero opex risk, no balance sheet impact.
Zero capital expenditure
PRE-FEASIBILITY ASSESSMENT
We help data center owners reduce energy use, recover excess heat, and strengthen sustainability performance. By integrating efficient heat-recovery systems to your cooling systems we lower operating costs and ensure compliance with EU energy-efficiency requirements. Calentix acts as both advisor and developer, making your energy systems smarter, cleaner, and more profitable.
FEASIBILITY STUDY
We support data center developers and landlords in creating more valuable and compliant sites. By connecting data centers to local district-heating networks, we turn waste heat into a new revenue stream and enhance your license to operate. Calentix designs, builds, and operates energy systems that make your facilities future-proof and attractive for your customers and investors.
PROJECT DEVELOPMENT
Once feasibility is confirmed, we structure the full project: technical design, permitting, contracts, and financing. Calentix acts as an independent heat producer, developing the project under an Independent Heat Produced model in cooperation with data center owners, utilities, and investors.
CONSTRUCTION AND OPERATION
We finance, build, and operate the heat-recovery system. We ensure performance, reliability, and long-term value. Over time, ownership can be structured in different ways depending on partner preferences and investment strategy.
YOUR OBLIGATIONS
What we need from you — and nothing more
A cooling circuit interface
Access to your liquid cooling circuit — typically a secondary loop at 25–35°C — at a defined isolation point. We design the interface to be non-disruptive to your operations.
Physical space
Typically 1–4 shipping-container equivalents for the heat pump installation. Containerised units available for constrained sites.
Electricity connection
The heat pump requires its own connection — typically 10–20% of the heat pump's thermal output in electrical terms. Given your existing electrical infrastructure, this is rarely a limiting factor.
Read-only data access
Temperature and flow rate in your cooling circuit, plus IT power draw. This feeds our monitoring platform and the ERF calculation — formatted for BfEE submission.
From first conversation to operational system: what to expect
PROCESS & TIMELINE
Phase 1 : Pre-feasibility (2–4 weeks)
Initial assessment of your facility: IT load, cooling configuration, temperature profiles, proximity to district heating. No commitment required.
Phase 2: Feasibility study (8–16 weeks)
Detailed technical and commercial analysis. Calentix produces a feasibility report confirming project viability, projected heat volumes and indicative commercial terms.
Phase 3: Partner alignment (parallel with Phase 2)
Calentix identifies and engages the district heating operator. This often runs concurrently with the feasibility study.
Phase 4 — Commercial structuring (8–12 weeks)
Negotiation and finalisation of the site agreement with the data centre and the HPA with the district heating operator. Legal and permitting processes run in parallel.
Phase 5 — Final Investment Decision (FID)
Once all agreements are signed and financing is secured, Calentix takes its Final Investment Decision. Construction begins.
Phase 6 — Construction and commissioning (12–24 months)
Installation of heat extraction equipment, system integration, testing and commissioning.
Phase 7 — Operations (15–25 years)
Calentix operates the system. You benefit from ERF performance and the ESG credentials of heat reuse — without any ongoing involvement.
SITE VIABILITY
What makes a good candidate?
Heat pumps require a water-based heat transfer medium. Liquid-cooled facilities
(direct liquid cooling, rear-door heat exchangers, or closed-loop cooling towers) are
the target market. Air-cooled DCs are not currently viable. As liquid cooling adoption
accelerates with AI/GPU workloads, the addressable market is expanding rapidly.The higher the cooling water return temperature, the better the heat pump performs.
A target of 25–35°C is ideal. Facilities below 20°C are significantly harder to make
work economically. This is the single most important technical variable.Facilities with an IT load above 2–5 MW are broadly in scope. Smaller installations can
sometimes be clustered or phased to reach viable scale. We are happy to screen
smaller sites.Projects within 1–2 kilometres of an existing network connection point are most attractive.
Longer distances require proportionally stronger heat volumes to justify the pipe
investment cost.The EnEfG's binding ERF targets and the Wärmeplanungsgesetz (requiring German
municipalities above 100,000 inhabitants to publish heat transition plans by June 2026)
create both regulatory compliance need and explicit municipal demand for DC waste
heat — making German projects exceptionally well-motivated.
Frequently asked questions
What is the Energy Reuse Factor (ERF)? The ERF is a metric defined under EU Delegated Regulation 2024/1364 that measures the proportion of energy consumed by a data centre that is subsequently recovered and reused — for example, as heat delivered to a district heating network. An ERF of 0.20 means that 20% of the data centre's total energy input is reused as heat elsewhere. The EU average across all reporting data centres (2023 data) is 0.019 — or 1.9%. Does recovering waste heat affect my data centre's cooling performance? No. The Calentix heat extraction system operates on the output side of your existing cooling infrastructure — it captures heat that your cooling system has already rejected. System design is validated against your cooling performance requirements before any equipment is installed. Your SLA uptime commitments are not affected. Who pays for the heat extraction equipment? Calentix finances, owns and operates all equipment. There is no capital expenditure for the data centre operator. Calentix recovers its investment through the long-term Heat Purchase Agreement with the district heating operator. Can the system scale as my data centre grows? Yes. Calentix designs systems with modular scalability in mind. Additional heat pump capacity can be added as your IT load increases, within the envelope of the original site agreement. What temperature does the waste heat need to be? The optimal input temperature depends on the specific installation. As a general principle, higher return temperatures from your cooling circuit allow for a more efficient heat pump configuration and lower cost per unit of heat delivered. Calentix conducts a detailed thermal analysis during the feasibility phase to determine the optimal system design for your specific cooling setup. Is this only relevant for hyperscale data centres? No. Calentix works with data centres from approximately 1 MW IT load upwards. The economic and regulatory case for waste heat recovery is strongest for larger facilities, but mid-size and edge data centres can also be viable depending on proximity to district heating infrastructure. What information do I need to provide to start a feasibility assessment? The most important inputs are: IT load (current and projected), cooling system configuration (type of cooling, set-point temperatures), and location. From this, Calentix can conduct an initial pre-feasibility assessment within 2–4 weeks with no commitment on your side.