It’s no secret that building a cleanroom is expensive. But over its lifetime, the cost of running one will almost always exceed the cost of building it.
In fact, the single biggest driver of cleanroom operating costs is usually the HVAC system.
According to a benchmark study by the Lawrence Berkeley National Laboratory, HVAC accounts for anywhere from 36 to 67 percent of total cleanroom energy consumption, though other sources put it even higher.
Luckily, a lot of these costs can be brought down without having to lower your cleanroom’s classification or compromise on compliance.
In this article, we’ll discuss the biggest contributors to cleanroom operating costs, as well as some of the best ways to reduce them.
Where Is the Money Spent in Cleanrooms?
Before you try to cut costs at random, it may help to know where exactly they’re coming from.
In most cleanrooms, the biggest expenses break down like this:
- HVAC and Air Handling. Think of heating, cooling, dehumidification, and fan power. This is by far the largest expense. Cleanrooms are 10 to 100+ times more energy intensive than a typical office building, and the HVAC system is the main reason.
- Filter Replacements. HEPA and/or ULPA filters need to be replaced periodically, and how often depends on how hard they’re working. If you put off replacements, the clogged filters force fans to work harder, which of course increases energy costs.
- Monitoring and Testing. Certification, recertification, and environmental monitoring. Stricter classifications of course require more frequent testing.
- Consumables and Maintenance. Gowning supplies, cleaning agents, wipes, and preventive maintenance are all recurring costs.
Make Sure You Don’t Over-Classify Your Cleanroom
So what can you do about it?
One of the simplest and most overlooked ways to reduce operating costs is to avoid over-classifying your cleanroom.
Every step up in ISO classification means more air changes per hour, more filter coverage, more energy, and more money.
If your process only requires ISO 7, running it in an ISO 6 space costs more for no benefit. The same goes for running an entire room at ISO 5 when only a specific zone needs it.
In many cases, using a laminar flow hood or workbench over the critical area within a less strict room is a much more cost-effective approach.
Getting the classification right from the start is one of the best things you can do for your budget.
Don’t Use More Air Than You Need
Air changes per hour is where the bulk of the energy goes, and a lot of cleanrooms run at higher rates than they actually need, either because the system was designed conservatively or because nobody optimized it after commissioning.
A few things worth looking into: lowering fan speeds during unoccupied hours and ramping back up before the next shift (one case study showed a 50 percent reduction in fan energy this way), running smoke studies to find where airflow is excessive, and installing variable frequency drives (VFDs) on fans so they’re not running at full speed 24/7.
Take Care of Your Filters
This one is straightforward but easy to neglect.
When pre-filters get clogged, they increase the pressure drop across the system, which makes the fans work harder, which uses more energy. Replacing pre-filters on a regular schedule protects your HEPA filters, extends their lifespan, and keeps the system running efficiently.
A HEPA filter that lasts an extra year or two because the pre-filters were doing their job can save you real money.
Fix Leaks and Seals
Duct leaks and worn door seals can also force the HVAC system to work harder, especially with regard to pressure differentials.
These are usually cheap and easy to fix, but again, it’s another easy problem to ignore. A small leak that goes unnoticed for months can add up to a surprisingly large increase in energy consumption.
Design for Efficiency at the Start
A lot of cleanroom operating costs are locked in at the design stage. The HVAC system size, the ceiling coverage, the pressure cascade layout, and the classification itself all determine what you’ll be paying every month for the life of the cleanroom.
This is where working with the right cleanroom manufacturer makes a massive difference. A well-designed cleanroom doesn’t just meet your classification; it does so without wasting energy.
Modular cleanrooms in particular can be designed with efficiency in mind from day one. And because they’re easier to reconfigure than stick-built rooms, you’re not locked into a design that no longer fits if your needs change.
At the end of the day, a cleanroom that was designed well, classified correctly, and maintained properly will cost less to run for as long as it’s in operation.
