How to Choose an Atlas Copco Air Compressor: A 6-Step Checklist for First-Time Buyers

When my manager told me in early 2024 that I'd be leading the purchase of a new air compressor, I nearly panicked. I'm an office administrator, not a mechanical engineer. I know how to order desk chairs and service contracts, but compressed air? Not my world. After three frustrating vendor meetings and one costly mistake, I ended up with a solid Atlas Copco unit that's still running without headaches. Here's the checklist I wrote for myself — you can use it too.

This guide has six steps. It's not a full engineering course. It's the nuts-and-bolts process that got me from “which button is the on switch?” to a compressor that actually does its job. If you follow it, you'll avoid the stupid mistakes I made.

Step 1: Confirm your real airflow and pressure — not what the sales rep suggests

It's tempting to think you can just pick a horsepower and move on. But the first number that matters is CFM (cubic feet per minute) at a given PSI. If you don't know those two numbers, you're guessing. And guessing is expensive.

Our mistake: I asked for “around 100 CFM” because that's what a competitor quoted. When the unit arrived, the production line kept tripping because the pressure tank couldn't keep up. The real demand was 140 CFM at 100 PSI. We had to run two shifts with a rented portable compressor until we swapped.

How to do it right: Walk through every piece of equipment that uses compressed air. Add their CFM ratings, then multiply by 1.25 to give yourself headroom. Don't forget to account for leaks — most plants lose 20–30% of air to leaks, so you'll need even more buffer.

According to Atlas Copco's compressor selection guides (atlascopco.com, accessed January 2025), oversizing by more than 10% can actually waste energy. It's a balance — you need enough, but not too much.

Step 2: Understand the different Atlas Copco air compressor models

Atlas Copco has a huge range. You'll see names like GA, GA VSD, ZD, and so on. Get familiar with the main types:

• Screw compressors — the workhorses for continuous use
• Piston compressors — cheaper but only for intermittent, low-duty jobs
• Centrifugal compressors — for massive industrial plants
• Portable compressors — for construction and temporary sites

The keyword is atlas copco screw. For most facilities, a rotary screw compressor is the right choice. It runs cooler, quieter, and uses less electricity than a piston unit of similar output. Even better, if you're running it more than 20 hours a week, a screw compressor will pay for itself in a couple of years.

But don't just look at the model name. Check the “VSD” (Variable Speed Drive) option — it can cut energy costs by up to 30% if your demand fluctuates. That might sound like a premium feature, but the payback often happens in 18 months.

Step 3: Oil-free or oil-injected? Don't gloss over this

This is where I got burned. I didn't have a formal specification process, so I never asked our quality lab about their requirements. The vendor suggested an oil-lubricated rotary screw unit, which is fine for many uses. But if your process is even a little bit sensitive to oil contamination, you'll be sorry.

What most people don't realize is that “oil-free” doesn't mean “no oil anywhere” — it means the compression chamber doesn't let oil touch the air. Atlas Copco's oil-free compressors (like the Z series) use water or special coatings to keep the air pure.

Our fix came when we sent a form to all department heads asking what they'd use the air for. One-line answer: “Quality lab needs oil-free.” So we switched to an oil-free model. It cost more upfront, but the cost of failed lab tests would've been worse.

If you're in food, beverage, pharmaceutical, or electronics manufacturing, go oil-free from day one. Don't let a salesperson talk you into “saving money” on a lubricated model.

Step 4: Plan for dryers, filters, and pressure drop

A bare compressor isn't a system. You also need:

• An air dryer — to remove moisture that ruins tools and products
• Filters — to catch particles and oil vapor
• Maybe a receiver tank — to smooth out pressure swings

Here's the part that surprised me: a dryer and filter set can drop your net pressure by 2–5 PSI. If your compressor is already borderline on pressure, that little drop can be the difference between a normal production day and a shutdown.

I remember opening the first quote and thinking they were overcharging for accessories. Turns out an Atlas Copco air dryer isn't a luxury — it's a necessity if you want your pneumatic tools to last more than a season. We cut a corner and bought an off-brand dryer. It failed in eight months. The second time it cost us a replacement; the third time I finally bought the proper one. Should've done it after the first failure.

Step 5: Check the service network and parts availability before you sign

An air compressor is a long-term purchase. You need spare filters, belts, and maybe a few wear parts. If your vendor can't supply them quickly, your expensive machine becomes a paperweight.

One thing the sales rep won't tell you: the base price of the compressor is only about 60% of the total cost over 10 years. The rest is energy and maintenance. So look for a service contract with fixed response times. If you plan to do your own maintenance, ask about the Atlas Copco service manual — but stick with authorized techs for major work.

Our vendor promised spare parts within 48 hours. When the first filter clogged, it took four days. We learned our lesson and now keep a starter kit of filters and belts on the shelf. The cost of the parts list was nothing compared to a production stoppage.

Step 6: Prepare the installation site — including ventilation and the thermostat issue

This is the step almost everyone forgets. A compressor room is not just a place to put a machine. The room needs enough air inflow and outflow to remove the heat the compressor generates. If you stick your compressor in a closet with just a window fan or a ceiling fan, it will overheat. Trust me — I watched our portable unit hit an alarm on the first hot day because the room had no proper exhaust.

Manufacturer guidelines specify minimum airflow for compressor rooms. For many Atlas Copco models, you need a cooling air flow of at least 5–10 times the compressor's frame volume per hour. A little ceiling fan just moves air around the room; it doesn't pull heat out. You may need an exhaust fan or ducted cooling.

Also, every compressor has a high-temperature cutout. If the room gets too hot, the controller will shut the unit off. The common question is how to reset thermostat on the controller. On most Atlas Copco units, there's a reset button on the Elektronikon display — press it after the compressor cools down. But don't just keep resetting it. If the machine trips on high temperature, find the root cause: poor ventilation, a faulty cooling fan, or a stuck external thermostat.

Some customers add an external room thermostat to control exhaust fans. That's smart — it starts the fan only when the room gets warm. But the fan itself should be rated for the airflow, not a cheap household model.

Three mistakes I learned the hard way

1. Ordering the compressor before the room was ready. The unit sat in a crate for two weeks while we ran ducting. The delivery guys charged us extra to come back.
2. Not checking the delivery access. The compressor was too heavy for our freight elevator. We ended up paying a crane service to bring it through a window opening.
3. Trusting a vendor's word without getting the specs in writing. We said “as soon as possible,” they heard “whenever convenient.” Now I always set a firm delivery date in the purchase order.

That's it. If you work through these six steps, you'll get a compressor that works, not one that just looks good in the brochure.

I'm not an engineer, and I'm not trying to tell you that this checklist replaces a proper engineering study. But for nearly every small and mid-sized company, this is the process that separates a good purchase from a painful regret.

Based on my own purchasing experience and Atlas Copco's published product information, current as of January 2025.