Walk into many legacy data halls and you’ll find the same thing: racks breathing air colder than the hardware needs, cooled by equipment sized for a load that changed a decade ago. For years, that waste stayed an internal line item. A growing number of building performance, emissions and data-reporting requirements in the US and Europe are bringing that inefficiency under greater regulatory scrutiny.

That shift turns efficiency in existing facilities from a good intention into an obligation with a deadline. It also puts the focus on the part of the industry with the most room for improvement: portfolios of enterprise data centers, network facilities and Edge sites that were built for different workloads and have been expanded piece by piece ever since.

Efficiency is becoming a reporting obligation

Building performance policy has moved well past a handful of early-adopter cities. More than 50 US states and cities now have benchmarking or performance requirements for large buildings on the books.

Colorado is a useful example of where these programs are headed. Its statewide program covers buildings of 50,000 square feet or more, and starting in 2030, HB25-1269 allows fines of up to $2,300 for every 30 days a covered building remains out of compliance with applicable performance standards, with higher penalties possible for subsequent violations.

Data centers in the program are measured against Power Usage Effectiveness targets. Operators can request a target tailored to their facility, but only with a detailed engineering audit to back it up. The flexibility goes to the operators who already have the data. New York City’s Local Law 97 assesses $268 for every metric ton of CO2 equivalent a covered building emits over its limit, and those limits tighten in 2030.

In Europe, Delegated Regulation (EU) 2024/1364 requires every data center with at least 500 kW of installed IT power demand to report 24 key performance indicators spanning energy, ICT and data traffic to a European database each year.

Operators are responding unevenly. Uptime Institute’s 2026 Global Data Center Survey found that the share of organizations actively collecting sustainability metrics has returned to a gradual upward trend, while carbon emissions tracking remains a minority activity. For facilities subject to these rules, incomplete operating data can become a compliance risk.

Legacy infrastructure holds the biggest efficiency gains

Demand growth raises the stakes. Lawrence Berkeley National Laboratory estimates US data centers consumed 192 TWh in 2024, about 4.7 percent of national electricity, and projects that share could reach 11.8 percent by 2030 in its reference case.

New, highly efficient AI capacity will carry much of this growth, yet the same Uptime survey found legacy infrastructure is slowing global efficiency progress, with average PUE improving only slightly this year.

Existing sites are where regulatory exposure and improvement potentially overlap, and where operators often have the least visibility. A portfolio assembled over 15 or 20 years typically runs several building management systems, cooling plants of different ages and set points chosen conservatively long ago and never revisited.

Retrofits that pay for themselves

The measures that recover efficiency in these facilities are well understood, and few of them require replacing major cooling equipment such as chillers, CRAC units or air handlers:

• Full-aisle containment, plus sealing of cable cutouts, floor gaps and missing blanking panels, so supply and return air stop mixing.
• Plenum repair to restore the underfloor static pressure that raised-floor cooling depends on.
• EC fan retrofits with dynamic controls, so fans track real thermal load instead of running at a fixed worst-case speed.
• Filter optimization to maintain required particulate protection while reducing unnecessary airflow resistance.
• Temperature set point optimization within the ASHRAE-recommended envelope of 18°C to 27°C (64.4°F to 80.6°F) for air-cooled IT equipment.

The last item is the most frequently overlooked. Many legacy rooms still deliver inlet air below the bottom of ASHRAE’s recommended range, wasting cooling energy the hardware doesn't need.

ENERGY STAR estimates data centers can save four to five percent in energy costs for every 1°F increase in server inlet temperature. Containment and airflow repairs are what make it safe to raise set points without creating hot spots.

Measure first, then verify every step

The order of operations determines whether these retrofits produce measurable, defensible results. The sequence that holds up is to establish a measured baseline with rack-level thermal and energy monitoring, make one category of change at a time and verify the result before moving to the next.

Documenting each step this way does three jobs. It confirms each intervention reduced thermal risk instead of adding it, it supports measurement and verification for utility incentive programs and it creates the auditable data trail that performance standards and disclosure rules require.

A recent Promera customer proof of concept at a national media and connectivity provider shows how this approach can work in practice. The operator runs six national data centers and roughly 600 local market sites, and cited state building performance legislation, alongside a corporate carbon-neutrality goal, as the reason to manage thermal load more dynamically. The team baselined a pilot site with real-time monitoring software, then layered in containment, filter changes and EC fan retrofits while tracking the effect of each.

Results to date include more than $50,000 in estimated cooling energy savings at an electricity price of roughly seven cents per kWh, a 1.79-year payback on the energy savings portion of the project and a potential 56 percent return on that segment.

Average rack temperatures rose a safe 7.2°F, and the number of racks running below 64.4°F, the floor of ASHRAE’s recommended range, fell by 31.5 percent. The same monitoring data now feeds the operator’s internal sustainability reporting and state compliance reporting, and it documented the project for a utility rebate.

Treat 2030 as a budget deadline

The low power price in that example matters. A retrofit that pays for itself in under two years at seven cents per kWh pays off even faster where electricity costs more. Add the fines an operator avoids by meeting its performance targets, and the payback period shrinks again.

With 2030 only three or four budget cycles away, operators should begin establishing baselines and sequencing improvements now. Organizations that act early can plan retrofits across their portfolios, pursue available incentives and enter mandatory compliance periods with years of verified performance data. Those that wait may face the same work on a tighter timeline, with less evidence to demonstrate progress.

Promera helps data center operators establish measurable baselines, identify airflow and cooling inefficiencies, implement targeted improvements and verify results across critical environments. Learn more about Promera.