The running cost of a cleanroom & energy conservation

Cleanrooms are notorious for being massively energy consumptive – often using far more power than a standard manufacturing facility of the same size. But why? And how can you tame those running costs without compromising performance or compliance? This post explores the factors driving energy use and practical ways to conserve it, all while recognising that no two Cleanrooms are alike.

 

Why Running Costs Vary So Much

Every Cleanroom’s energy bill is unique, shaped by its specific user requirements, electrical setup, and environmental parameters. This is why it is difficult to provide running cost figures without going into the fine detail of a specific Cleanroom’s design. A small ISO 8 electronics assembly room will sip power compared to a vast ISO 5 pharmaceutical or microelectronics suite, but even similar facilities can differ wildly based on:

  • ISO classification and size: Lower classes demand exponentially more air changes per hour (ACH), pushing up fan and filtration loads.
  • Environmental controls: Tight tolerances on temperature, humidity, or airborne molecular contamination require constant conditioning, often with chillers, humidifiers, or chemical scrubbers.
  • Process demands: High-heat tools, exhaust-heavy wet processes, or 24/7 operation amplify electrical draw from equipment and support systems.
  • Building factors: Local climate, insulation quality, and even utility rates play a role. A Cleanroom in a humid environment will fight harder against moisture ingress than one in a dry zone.

These variables mean a one-size-fits-all calculation is impossible. Running costs are a bespoke equation: start with baseline HVAC demand, add process electrics, factor in monitoring and lighting, then apply site-specific multipliers. The result? Facilities where energy is the single largest ongoing expense, often dwarfing labour or materials.

 

Key Drivers of Energy Costs

At the heart of most Cleanroom power use is the HVAC system . Fans run non-stop to maintain positive pressure and filtration, while heating/cooling coils battle to hold steady conditions. Other big drivers include:

  • Filtration and airflow: HEPA/ULPA filters create resistance, forcing fans to work harder. High ACH in critical zones ramps this up.
  • Electrics and utilities: Process tools, pumps, compressors, and monitoring systems add steady loads.
  • Lighting and peripherals: Traditional fluorescents or over-specified lux level LEDs can nibble away, especially in large spaces.
  • Inefficiencies from over-design: Specifying tighter controls than truly needed (e.g., ±0.1 °C when ±2 °C would suffice) wastes energy round the clock.

 

 

Methods for Energy Conservation

Smart design and operation can slash consumption without risking product quality. Here are some proven strategies:

  • Recirculated air systems: Instead of a 100% fresh air, recirculate filtered air where possible. This cuts conditioning loads by reusing already treated air. Note though for certain processes such as where hazardous substances are being handled within the cleanroom, a 100% fresh air system may be a necessary requirement.
  • Decentralised vs setback modes: Fan Filter Units (FFUs) allow zoning – run only what’s needed in active areas. For centralised HVAC, implementing night/weekend setbacks can be an option if the process / product allows for it: reduce air change rates and relax parameters during downtime while maintaining basic positive pressure.
  • Innovative HVAC design: Use variable-speed drives (VSDs) on fans and pumps to match output to real-time demand. Heat recovery wheels or economisers reclaim waste energy from exhaust. Hybrid systems (AHU + FFUs) optimise for high-ACH zones without oversizing the whole plant.
  • Scrutinise at design stage: Challenge every URS line item: is ultra-low humidity essential, or can it be relaxed? Tailor parameters bespoke to the process – no blanket specs. This “right-sizing” eliminates waste from day one.
  • Efficient lighting and peripherals: Switch to LED with occupancy sensors (PIR) and daylight integration. Optimise monitoring systems to sample rather than continuously poll.

These steps can transform a power-hungry cleanroom into a leaner operation, often with quick paybacks through lower utility bills and greener credentials.

At Angstrom Technology, we specialise in energy-optimised Cleanroom designs that balance performance and efficiency. Contact us for a free energy audit or design review – let’s calculate what’s possible for your facility.