- The Kilowatt Billing Standard: Modern colocation providers rarely bill by square footage or rack units (RU); they bill primarily for power draw, ranging from $150 to $350 per kilowatt (kW) per month including cooling and UPS backup.
- PUE Pass-Through Mechanics: Power Usage Effectiveness (PUE) measures data center energy efficiency. A facility with a 1.2 PUE consumes 0.2 kW of cooling and facility power for every 1.0 kW of server compute, impacting utility pass-through billing.
- Rack Density Arbitrage: Designing 42U racks to accommodate 15 kW to 25 kW of dense compute maximizes server density per cabinet, slashing cross-connect costs and floor space expenses by up to 60%.
How Do Colocation Facilities Actually Bill for Power?
When engineering teams prepare for cloud repatriation as detailed in our AWS to bare-metal repatriation blueprint, the most unfamiliar financial variable is power accounting. In the public cloud, electricity is an invisible cost hidden inside inflated instance hourly rates. In a colocation data center, power is the single largest operational expense.
Under Breakered Power billing, if you order an A+B redundant 208V 30A circuit pair, the data center bills you for 4.99 kW of usable power (utilizing the National Electrical Code 80% continuous draw rule) regardless of whether your servers draw 1 kW or 4 kW. Under Metered Power billing, smart PDUs measure exact kilowatt-hour consumption, offering lower costs for variable workloads.
Understanding PUE and High-Density Rack Economics
Historically, legacy enterprise data centers supported only 4 kW to 6 kW per 42U rack. However, modern 1U dual-socket AMD EPYC servers draw 400W to 700W each. Stacking twenty modern nodes into a single rack creates a 12 kW to 15 kW thermal load. Deploying in facilities that support high-density cold-aisle containment avoids stranding empty rack space, optimizing physical footprint as explored in our ClickHouse bare-metal performance guide.
By maximizing density per cabinet, enterprises minimize the number of physical racks needed. Because each cabinet incurs fixed charges for space, security, and meet-me room network drops, consolidating high-density hardware into fewer racks yields dramatic ongoing savings.
| Data Center Parameter | Low-Density Legacy Colo (5 kW) | High-Density Modern Colo (15 kW) | FinOps Variance |
|---|---|---|---|
| Cabinets Required (60 kW total load) | 12 Cabinets | 4 Cabinets | 66% reduction in rack footprint |
| Facility PUE Efficiency | 1.60 to 1.80 PUE | 1.15 to 1.25 PUE | 30% lower cooling energy waste |
| Cabinet Space & Cross-Connect Fees | ~$4,800 / month ($400/rack) | ~$1,600 / month ($400/rack) | $3,200/mo floor space savings |
| Effective Power Cost per kW | ~$320 / kW-month | ~$190 / kW-month (Volume scale) | 40.6% cheaper effective energy rate |
Why Colocation Power Beats Public Cloud Compute Pricing
When you account for physical server amortization and colocation power, the total cost of operating owned hardware is a fraction of cloud instance leases. Furthermore, modern servers operating under immutable Linux operating systems achieve near-zero maintenance overhead, dispelling the myth of high facilities labor.
People Also Ask
What is the difference between A and B power feeds in a data center?
A and B power feeds are two completely independent, redundant electrical circuits backed by separate UPS battery banks and diesel generators. If Feed A fails, Feed B sustains 100% of the server load without interruption.
What is the 80% continuous load rule for data center power?
Under National Electrical Code (NEC) standards, electrical circuits must not run above 80% of their rated capacity for continuous loads exceeding three hours (e.g., a 30-amp circuit has a continuous capacity of 24 amps).
How do smart PDUs help manage colocation power costs?
Smart Power Distribution Units (PDUs) monitor real-time voltage, amperage, and power factor per outlet, alerting engineers before circuits hit overload thresholds and providing exact telemetry for metered billing audits.
Related Colocation Datacenter Engineering:
Before selecting CPU power envelopes for your server deployments, review our comprehensive audit on AMD EPYC vs. Intel Xeon: Colocation Server CPU TCO Guide.
Related Colocation Facility Infrastructure:
To calculate power density and rack colocation costs when deploying regional Anycast POPs, examine our breakdown of BGP Anycast Routing Architecture: DNS & Edge CDN Guide.