What Temperature Should A Data Center Be? (Ashrae Guidelines Explained) August 4, 2026 Data center temperature requirements have evolved significantly over the past decade. The 'colder is safer' assumption that dominated early data center design has given way to a more nuanced understanding: the right temperature is one that supports reliable equipment operation while optimizing energy efficiency — not the lowest temperature you can achieve. ASHRAE Recommended Temperature Ranges ASHRAE's Thermal Guidelines for Data Processing Environments (ASHRAE 90.4 and TC 9.9 publications) provide the industry standard framework. For IT equipment air intake temperature: ASHRAE Class Recommended Intake Range A1 (most sensitive legacy equipment) 59-77 degrees F (15-25 degrees C) A2 (most enterprise equipment) 50-95 degrees F (10-35 degrees C) A3 (modern equipment) 41-104 degrees F (5-40 degrees C) A4 (latest generation) 41-113 degrees F (5-45 degrees C) For practical planning purposes, most modern enterprise data centers target server inlet temperatures of 64-77 degrees F (18-25 degrees C). This range balances equipment reliability with cooling efficiency. Why Colder Isn't Better Running a data center colder than necessary carries real costs with no reliability benefit: Lower chilled water setpoint requires more chiller energy to achieve Lower facility temperatures increase the risk of condensation if humidity isn't tightly controlled Equipment manufacturers have validated equipment to operate safely at much higher temperatures than many facilities actually run "There's a shift toward running warmer — but only when the system is designed to support it. The goal isn't arbitrary warming; it's matching temperature to what the equipment and workload actually require."— Justin Thomas, General Manager, G&D Chillers Temperature and Rack Density Interaction Higher rack density limits temperature flexibility. At 5 kW per rack, inlet temperatures can vary more widely without creating hot spots — the heat density is low enough that air mixing handles it. At 30-80 kW per rack, temperature must be controlled tightly because the consequences of a hot spot are immediate and severe. Rack Density Temperature Management Requirement Under 10 kW per rack Significant flexibility; standard air cooling with basic containment adequate 10-20 kW per rack Careful airflow management required; hot/cold aisle containment essential 20-40 kW per rack Tight temperature control needed; supplemental liquid cooling often added 40+ kW per rack Liquid cooling typically required; air-side temperature management alone insufficient Chilled Water Temperature for Data Centers Data center chilled water setpoints are typically higher than commercial HVAC applications. Where HVAC systems target 44 degrees F chilled water supply, data center cooling systems (particularly those serving liquid cooling CDUs) often operate at 55-65 degrees F supply temperature for the IT loop. Higher supply temperature enables more efficient chiller operation and can support economizer hours in cooler climates. Frequently Asked Questions What happens if server inlet temperature exceeds ASHRAE recommendations? Modern servers have multi-stage thermal management: fan speeds increase, performance throttles, and if temperatures continue to rise, thermal shutdown protects the hardware. The progression is: efficiency loss then performance degradation then automatic shutdown then hardware damage. Can I run warmer to improve PUE? Raising supply air temperature (and correspondingly raising chilled water setpoint) directly improves chiller efficiency and increases economizer hours, improving PUE. This is a well-established optimization strategy. The prerequisite is confirming your IT hardware is validated for the higher inlet temperatures you intend to run. Talk with G&D's engineers to optimize your cooling strategy -> Contact us