Questions to Ask Suppliers When Requesting Air Compressor Quotes

OEM brand and airend brand are often not the same thing. Some OEMs buy airends externally, assemble them, slap their own name on and sell. Atlas Copco, GHH-RAND, TMC, Hanbell, Fusheng are common airend suppliers. Machining precision and design levels vary, price tiers are spread apart. Knowing the airend source is more useful than looking at the OEM brand.

Rated life typically 80,000 to 100,000 hours. Warranty 1 to 2 years or a few thousand hours, whichever comes first.

Motor is the big power eater. IE2 is high efficiency, IE3 premium, IE4 super premium. Each step up saves 2 to 3 percentage points on energy. Compressors run thousands to tens of thousands of hours. That percentage point times hours times electricity price, the number gets big. ABB, Siemens, WEG are common imports.

Only applies to variable frequency models. ABB, Siemens, Schneider, Danfoss, Inovance, Invt all get used.

Specific power = input power ÷ discharge volume, kW/(m³/min). Lower number means less electricity per unit of air. Best single metric for energy efficiency, also the easiest for manufacturers to game with test conditions. 20°C inlet vs 35°C inlet, numbers differ a lot. 7 bar discharge vs 8 bar, also different. When asking, get the test standard (national or ISO) and operating parameters together, otherwise numbers from different suppliers can't be compared.

Measured at 1 meter vs 3 meters differs by about 6 dB. Check the test distance for the rated value.

Air-cooled is simpler. Water-cooled needs a cooling tower or water system, noticeably more investment and maintenance.

Dryer, filters, receiver tank, remote monitoring. Some suppliers include these as standard, some charge extra. Have the supplier list the full configuration.

Can it go online, can it do multi-unit sequencing, can it log data. Ask about these.

The separator element is the big consumable. Different brands range from tens of dollars to several hundred. Replacement intervals 3,000 to 8,000 hours. Some machines are cheap to buy, expensive on consumables. After a few years the total actually costs more. Calculate this separately.

Standard consumables, 2,000 to 4,000 hours.

Mineral is cheap, changed more often. Synthetic is expensive, changed less. Total cost may not differ much. Do the math.

New machines need first service around 500 hours. Clarify who pays.

1 year or 2 years. Wear parts covered? Electrical parts covered? Make the supplier spell it out. Vague warranty terms lead to disputes when things go wrong.

4 hours and 24 hours are very different things. Production line sitting there waiting for the compressor, one day's losses might be more than the machine. Put this in the contract.

Warranty always ends. Know the post-warranty repair cost structure upfront.

Matters a lot in remote areas. Machine sitting idle waiting for parts, one week vs one month, two very different things.

Local means faster response. No local center, all service depends on sending someone out. Time and money, both a problem.

Common is 30% advance, 60% on delivery, 10% on acceptance.

Standard models might have stock. Custom needs production scheduling.

Equipment is heavy. Shipping and rigging aren't small numbers.

Some include it, some don't. Commissioning billed by man-day, travel on top.

If cases exist, call and ask how it's been going.