By a mid-size data center I mean a site with 0.5–3 MW of IT load and a few hundred to a couple of thousand square meters of floor. A bank, an online store, a government agency or a factory builds one for itself. A colocation provider rents it out by the rack to companies that cannot afford a hall of their own.
The base is a consolidated research report with indicative prices for Europe, the US and Asia. I checked reliability and efficiency against Uptime Institute surveys and construction cost against the JLL forecast. Along the way I found several inconsistencies in the report and deal with each where it comes up.
Capacity, reliability, efficiency
The first inconsistency is scale. The report describes 50–80 racks and 300–800 servers as a 0.5–3 MW data center. But 50–80 racks at 5–6 kW give 250–480 kW. At 10 kW per rack, 3 MW needs 300 racks, and power and cooling grow about sixfold. So the tables below describe a site of about 0.5 MW. Larger capacity is built in phases without shutting down the running hall, while the utility feeds, cooling and cable routes are designed for full capacity from day one.
The reliability standard for a mid-size data center is Tier III in the Uptime Institute classification. Every critical power and cooling component has a spare (N+1), and distribution has a second path. Any component or line can be taken out for maintenance without stopping the servers, and that is exactly what certification tests. Tier III availability is usually put at 99.982%, about 1.6 hours of downtime a year. Tier IV with full duplication (2N) costs noticeably more.
Average rack power is creeping from roughly 5 kW toward 8 kW and has not reached 8 yet (Uptime Institute, 2024 survey). A typical enterprise data center runs at 4–6 kW. Racks of 10–30 kW are becoming more common because of AI workloads; above 30 kW they are still rare. If AI is in the plan, the liquid-cooling zone goes into the design at once: room, routes, floor loading, connections for CDUs and manifolds. Adding it to a live hall later means shutting the hall down.
PUE is how much energy the whole facility draws per kilowatt of IT load. According to the Uptime Institute 2025 survey, the global average PUE is 1.54 and has barely moved for six years. Europe is at 1.50, North America at 1.49, China at 1.40, Latin America at 1.65. Each 1 MW of servers carries about 0.5 MW of cooling, losses and lighting. Free cooling brings PUE down to 1.3–1.4.
Electricity is budgeted separately from construction. A rough example for 3 MW at 75% average load and a PUE of 1.4: 3,000 kW × 0.75 × 1.4 × 8,760 hours = 27.59 million kWh a year. At $0.10 per kWh that is $2.76 million. Capacity charges, grid fees and taxes can change the total several times over.
Construction, according to the JLL forecast, costs $11.3 million per MW on the global average in 2026, 6% more than in 2025. That excludes land and servers and is modeled on a large facility. Silicon Valley and Tokyo come in above $15 million, India and Southeast Asia below $8 million. For 3 MW this is a benchmark; the budget comes from the design.
Equipment
Quantities are for a data center of about 0.5 MW, prices are per unit in Europe. In the US, by the report’s estimate, prices in dollars are almost the same; in Asia they are 20–35% lower.
Servers, storage, network
| Item | Quantity | Price |
|---|---|---|
| 2U server: 16–32 cores, 128–256 GB RAM | 100–300 | €3,000 |
| 1U server: 8–16 cores, 32–64 GB RAM | 200–500 | €1,500 |
| Blade chassis, 10U | 2–4 | €10,000 |
| Blade server: 24–32 cores, 64–128 GB RAM | 10–20 | €4,000 |
| Storage array, 24–48 drives, 100–300 TB | 2–4 | €30,000 |
| Top-of-rack switch, 48 ports 1/10GbE | 10–30 | €5,000 |
| Aggregation switch, 32 ports 10/40GbE | 3–8 | €15,000 |
| Router with BGP/MPLS | 1–3 | €10,000 |
| Optical transceiver 10/40/100GbE | 50–200 | €100–300 |
Server prices in the report are a floor. From September to December 2025, enterprise memory from Dell, HPE, Lenovo and Cisco rose 28%, SSDs and HDDs 30–40% per gigabyte, and servers themselves 5–10% in December (Context, The Register, January 2026).
Racks and cabling
| Item | Quantity | Price |
|---|---|---|
| 19″ 42U rack, 800 × 1000 mm | 50–80 | €800 |
| Perforated rack door | 50–80 | €100 |
| 1U patch panel | 10–20 | €200 |
| Cat6 patch cord, 1–5 m | 500–2,000 | €2 |
| OM3/OM4 fiber | 1,000–2,000 m | €1 per meter |
| Cat6 twisted pair | 1,000–2,000 m | €1 per meter |
| Copper power cable, 35–240 mm² | 1,000–2,000 m | €5 per meter |
Power
| Item | Quantity | Price |
|---|---|---|
| Modular double-conversion UPS, 100–600 kVA | 2–4 | €50,000 per 100 kVA |
| Battery cabinet | 8–16 | €5,000 |
| Automatic transfer switch, 3-phase, 400 V | 2–4 | €2,000 |
| Diesel generator, 500–1,000 kVA | 2–3 | €100,000 per 500 kVA |
| Fuel tank, 20–50 m³ | 2–3 | €10,000 |
| Transformer 6–20/0.4 kV, 1,000–3,000 kVA | 2–4 | €30,000 |
| Main switchboard | 1–2 | €8,000 |
| Incoming distribution board, 250–1,250 A | 2–4 | €3,000 |
| Distribution cabinet, 200–1,000 A | 4–8 | €5,000 |
UPS systems are often built 2N even when the rest of the plant is N+1.
The second inconsistency: the report labels the tanks “one day of fuel”. A generator burns roughly 0.25 liters of diesel per kWh. A 0.5 MW site with cooling needs about 0.75 MW, which is 4.5 m³ a day. One 20 m³ tank runs it for four days, three 50 m³ tanks for more than a month. Uptime Institute requires at least 12 hours at full load, not counting the redundant tank. The rest is a question of how much autonomy you want and what your fuel delivery contract says.
Cooling
| Item | Quantity | Price |
|---|---|---|
| Precision air conditioner (CRAC), 30–150 kW | 3–6 | €20,000 |
| Chiller, 100–1,000 kW | 1–2 | €50,000 per 200 kW |
| Indoor unit (CRAH, fan coil), 10–50 kW | 5–10 | €3,000 per 10 kW |
| Circulation pump, 5–30 kW | 4–6 | €2,000 |
| Piping, 21–219 mm diameter | 500–1,000 m | €10 per meter |
The third inconsistency: the table mixes two designs. CRAC units run on refrigerant by themselves, CRAH units on chilled water from a chiller, and a site usually picks one. With chillers, Tier III needs at least two; otherwise the first service visit stops the cooling.
Safety, monitoring, lighting
| Item | Quantity | Price |
|---|---|---|
| Gas fire suppression (Inergen, FK-5-1-12) | 1 system | €20,000 |
| Pre-action sprinklers for corridors | 1 system | €10,000 |
| VESDA aspirating smoke detection | 5–10 detectors | €5,000 per system |
| DCIM software and sensors | 1 | €50,000 |
| Temperature sensor | 10–20 | €100 |
| Humidity sensor | 5–10 | €150 |
| IP camera, access control | 10–20 cameras | €500 per camera |
| Fire extinguisher | 10–20 | €50 |
| LED light fixture | 50–100 | €50 |
| 230/400 V socket | 100–200 | €20 |
The report suggests Inergen and Novec for gas suppression. Novec 1230 is no longer made: 3M ended PFAS production at the end of 2025. Other manufacturers make the same molecule, FK-5-1-12; before ordering, check what a refill costs and who will supply it ten years from now.
Add 3–5 installation kits at €1,000, 2–3 cable and insulation test kits at €2,000 and about €500 of consumables: cable ties, markers, labels.
What the tables leave out
These purchases usually hide inside “construction cost”. Each one gets its own package with a price and an owner.
| Package | What it includes |
|---|---|
| Grid connection | Utility approval, capacity contract, connection fee, cable routes |
| Grounding and busbars | Earthing system, main grounding bar, busways between switchboards |
| Connectivity | Two independent fiber routes, two building entries, two meet-me rooms, OTDR testing |
| Diesel plant | Fuel filtration and testing, backup fuel pumps, emergency delivery contract |
| Batteries | For lithium-ion: overheating, off-gas and fire analysis; NFPA 855 in the US |
| Spare parts | Fans, boards, power supplies, pumps, sensors, filters, generator oil |
| Emergency backup | Rental contract for mobile generators and cooling, temporary hookup points |
| Control-system security | Isolated network for BMS, DCIM and EPMS, logged contractor access |
| Installation and oversight | Rigging for transformers and chillers, cargo insurance, independent site supervision, factory acceptance tests |
| PPE and tools | Insulated gloves and footwear, arc-flash protection, thermal camera, power quality analyzer |
| Cleaning | By procedure: ESD-safe equipment, HEPA vacuums; cleanliness target ISO Class 8 per ASHRAE |
People
| Role | Headcount | Annual salary, Europe |
|---|---|---|
| Data center manager: processes, SLAs, contractors; 8+ years of experience | 1 | €120,000 |
| Systems administrator: servers, storage, virtualization | 1 | €80,000 |
| Network engineer: switches and routers | 1 | €90,000 |
| Electrical engineer: UPS, generators, switchboards, transformers | 1 | €100,000 |
| HVAC engineer: chillers, air conditioners, ventilation | 1 | €90,000 |
| Duty operator, 24/7 in shifts | 4–6 | €40,000 |
| Security and access control, in shifts | 3–6 | €30,000 |
| Cleaning | 2–3 | €25,000 |
Salaries are per person. IT, engineering, the duty shift, security and cleaning report to the manager.
Add up the rows and you get 14–20 people and €0.78–0.98 million in salaries a year. The report puts total staff lower, at 10–15 people excluding contractors. For scale: JLARC (December 2024) estimates that an operating data center in Virginia supports about 50 jobs. In the US the same roles pay 20–25% more in dollars than Europe pays in euros; in Asia they pay 2–3 times less.
The fourth inconsistency is in the lower bound. A 24/7 post is 8,760 hours a year; at 1,800 working hours per person it takes 4.9 full-time staff. Four duty operators cannot cover one post without overtime, and three guards even less so. Six cover it with room for vacations.
UPS, generator, chiller and fire suppression servicing goes to contractors, about 10–20% of operating costs. The Owner’s Engineer and the commissioning lead are hired for the project.
How the launch goes
- Design
- Construction
- Installation
- Commissioning
- Design: two months on architecture, one on electrical and HVAC; in parallel, a month and a half of approvals and tenders.
- Construction: two months on foundations, two on walls, floor and roof, one on electrical work and utility feeds.
- Installation: a month each for power, cooling, and racks with servers and network.
- Commissioning: 15 days to test power and grounding, 15 for HVAC and access control, 20 for integrated testing and handover.
The 20 days of integrated testing decide whether the facility is accepted. ASHRAE splits commissioning into five levels, from factory testing at L1 to integrated systems testing at L5. A generator, a UPS and a chiller that each work on their own prove nothing yet. At L5 you show that:
- utility power is lost — the servers keep running;
- one generator fails — the backup has enough capacity;
- a UPS is in maintenance — redundancy holds at design level;
- a chiller fails — temperature stays in range;
- a carrier goes down — traffic moves to the second route;
- a BMS controller fails — the plant stays under control;
- one section is de-energized — the others keep working.
The scenarios are run by an independent commissioning agent hired separately from the general contractor.
Run back to back, the stages add up to about a year; overlapping, the report fits them into seven months. That is the fifth inconsistency: seven months is possible only if the transformers are already ordered and the grid connection is in hand. In the US a data center building usually takes 18–24 months from groundbreaking to handover. Large power transformers ship in two to four years, and grid connections take four years on average (JLL, 2026 forecast). In a real project the longest item is electricity.
What to settle before the specification
A list of screws and cables may turn out wrong if it was drawn up before the model. The owner decides what to build; the designer turns that into equipment. Five decisions before the first specification:
- Business model: your own hall or colocation, and who pays for the rack.
- IT capacity by phase: how much in the first phase and how much at full build-out.
- Reliability: Tier III with concurrent maintenance, or Tier IV.
- Connectivity: two carriers, two routes, two meet-me rooms.
- Cooling: air, liquid, or space for liquid from day one.
From the lead designer, five documents: a bill of materials and quantities (Master BOM/BOQ); a design document register with schematics and thermal calculations; a test register covering all five levels; operating procedures with spare parts and service contracts; a financial model with CAPEX and OPEX by phase. Each purchase line carries, besides the price, the lead time, warranty, service life and maintenance cost. The standards for this stage are the Uptime Tier Standard, ISO/IEC 22237 and TIA-942.