What Size Air Compressor Do I Need? Is 24 or 50 Litres Enough?

Your compressor can't keep a sander going, or you're torn between 24 and 50 litres.

Match free air delivery (FAD) to the air your tools use; the tank comes second. PartsForMachines lists over 100 compressors from FSN, SIP, Clarke, Sealey, NuAir and Draper, plus dryers, receivers and drains, in its Direct Drive Compressors range.

How Do I Work Out What Size Compressor I Need?

Add up the air used by the tools you will run at the same time, then pick a compressor whose free air delivery covers that total with room to spare. Check each tool's air use in its manual. Sanders and spray guns use far more air than a nailer or tyre inflator.

For example, keep the tools you run together within the 7 CFM FAD of the SAC10030VA 100-litre compressor and its pressure stays steady. Compare FAD, not displacement: displacement is the higher figure on every model here that quotes both.

Is a 24- or 50-Litre Compressor Big Enough?

For tyres, blow-off work and light air tools, 24 litres is usually enough; for heavier work, check the FAD before the litres. The tank only stores air, and the pump makes it: the 50-litre SAC5002 and the 100-litre SAC10002 both deliver 9.64 CFM FAD.

A bigger tank gives longer bursts and fewer motor starts, which helps with tools used in short spells, as stored air tops up what the pump makes. For a tool that runs non-stop, such as a blast gun, the pump's FAD must cover its air use; a second tank only delays the pressure drop.

Will a Small Compressor Cope With Continuous Use?

Often not, so check the duty cycle or run-time limit before you buy. Some compact units set a firm limit; the 05323 AirHub wall-mounted compressor, for example, should not run longer than five minutes at a time.

Run a piston pump too long without a rest and it can overheat; the thermal overload may then stop the motor. If it trips, unplug the compressor and let the motor cool before restarting. For long sanding or blasting sessions, choose a compressor with plenty of FAD to spare, so the pump gets time to cool between cycles.

Oil-Free or Oiled: Which Should I Choose?

Choose oil-free for spraying and low upkeep. It needs no oil, so on a machine such as the SAC5002, no oil can reach the paint. An oiled pump needs its oil checked and changed at the intervals in its manual.

Oiled pumps can pass traces of oil into the air, so fit a suitable filter before spraying. For long daily use, compare the duty rating or run-time limit of each model, whichever type you choose.

What Should I Check Before I Buy?

• FAD that covers every tool you will run at the same time, with headroom.
• Maximum pressure: most models here run to 8 bar (116psi), some to 10 bar (145psi).
• Duty cycle or run-time limit, if your tools will run for long spells.
• Oil-free for spraying and low upkeep, or oiled with a suitable filter.
• Supply (13A, 16A or 110V) and the noise rating in dB.

Not sure which suits your tools? Contact the PartsForMachines team by WhatsApp, telephone or email with the tools you run and your power supply, or browse the Direct Drive Compressors range.

Product options, delivery options and returns terms are shown on each product page. A 30-day return policy applies to eligible items.

Frequently Asked Questions

Does a bigger motor mean more air?

Not reliably, so compare FAD rather than horsepower. Two 3hp, 100-litre machines show the gap: the SAC10030VA delivers 7 CFM FAD, while the 05494 low-noise compressor delivers 13 CFM FAD, nearly twice as much.

What pressure do I need: 8 or 10 bar?

Enough for the working pressure given in your tools' manuals; set the regulator to each tool's figure. Most compressors here run to 8 bar (116psi). Some, such as the SAC5002, reach 10 bar (145psi), which leaves more in hand.

Will a small compressor run a spray gun?

Only if its FAD covers the gun's air use, which is often high, so check the gun's figure first. Small quiet units suit airbrushing. For painting, oil-free air and a moisture filter or dryer help prevent flaws in the finish.

Will it run on a 13A plug or a 110V site supply?

Many 3hp direct-drive models run on 13A. The 4.5hp QT AIR models need a 16A supply and start through a control box. For sites with only 110V, the SAC2420E110V 24-litre compressor runs on a 110V 16A supply.

How quiet can a compressor be?

Very quiet, if you choose a low-noise model. Many standard direct-drive machines are rated at 94 to 97dB(A), while the 05494 low-noise compressor runs at 62dB with a 3hp motor. Some small quiet-run units are rated at around 43dB.

Do I need a moisture filter or air dryer?

Yes for spraying, and it helps tools last. Water vapour in compressed air condenses as the air cools, which can spoil paint finishes and wear tools. Fit a moisture filter or, on a workshop system, a dryer such as the PS9 compressed air dryer.

How often should I drain the tank?

Daily, after use, unless it has an automatic drain: trapped water corrodes the tank and weakens its walls over time. On a workshop receiver or air line, an automatic drain such as the EMD12 condensate drain discharges it for you.

Can I use an old gas bottle or water tank as an extra receiver?

No. Use only a receiver built for compressed air, rated above your compressor's maximum pressure and fitted with a safety valve: a weak or unsound vessel can rupture. Our vertical receivers are rated from 11 to 16 bar.

How can I tell if the check valve is leaking?

Listen and watch the tank gauge after the compressor cuts out. If air keeps hissing from the pressure switch and the gauge keeps falling, the check valve is probably leaking. A faulty valve can also make the motor hum or trip on restart.

Is a 12V inflator enough for tyres?

For tyres alone, often yes. The 99074 12V inflator is rated at 2 CFM at up to 150psi and can inflate car, 4x4 and light commercial tyres. For blow-off work or air tools, choose a larger compressor with a tank.