Oil-free or oil air compressor
Updated: 21.10.2026
The choice is cleaner day-to-day air against a pump built for more regular running, and it is not a choice between wet air and dry air. If you are deciding on an oil-free or oil air compressor for spraying, nailing, or a workshop that runs most days, the four amazon.co.uk listings in the [100 L air compressor comparison](/hub/compressors/100l-air-compressor) already split. Both SIP Airmate models are oil-free. The TIGREN is splash-lubricated on the listing. The Sealey Amazon page is silent, and Sealey’s own sheet shows a sump. Prices stay on the comparison. No lab test. A qualifying purchase can earn a commission at no extra cost to you.
The choice is cleaner day-to-day air against a pump built for more regular running, and it is not a choice between wet air and dry air.
The choice is cleaner day-to-day air against a pump built for more regular running, and it is not a choice between wet air and dry air. If you are deciding on an oil-free or oil air compressor for spraying, nailing, or a workshop that runs most days, the four amazon.co.uk listings in the 100 L air compressor comparison already split. Both SIP Airmate models are oil-free. The TIGREN is splash-lubricated on the listing. The Sealey Amazon page is silent, and Sealey’s own sheet shows a sump. Prices stay on the comparison. No lab test. A qualifying purchase can earn a commission at no extra cost to you.
Our top picks
| Badge | Product | Lubrication | Oil fill | Free air delivery | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  Sealey Sealey SAC10030VA 100L | Oil on Sealey’s sheet | 350 ml on the sheet | 7 cfm on Sealey’s sheet | 4.7 | about £351.23 | View offer |
| Preis-Tipp |  TIGREN TIGREN V100DD 100L | Splash lubrication | Not stated on Amazon | 8 CFM on SIP page | 6.7 | about £347.99 | View offer |
 SIP SIP Airmate 100L vertical | Oil-free on the listing | No sump | 9 CFM at 8 bar | 7.2 | about £479.98 | View offer |
On this page
What the four listings are
An oil-free pump in this class has no sump to check and no oil change. The vertical SIP Airmate 05484 and the horizontal SIP Airmate 05481 both say oil-free on the amazon.co.uk listing, and SIP’s pages for those models repeat it. Each of those maker pages states 9 CFM free air delivery. Amazon states that free-air figure only on the vertical model. On the horizontal model Amazon says 15 CFM and does not call it free air delivery, so the lubrication is clear and the airflow label is not.
A splash-lubricated pump flicks oil onto the moving parts from a small sump. The TIGREN V100DD listing says oil-lubricated and names splash lubrication. SIP’s page for 04388 states 8 CFM free air delivery. Amazon’s 13 CFM on that listing is unlabelled. Oil capacity is not on the Amazon page, so the fill comes from the manual and the sight glass.
The Sealey SAC10030VA is the awkward one. The Amazon listing does not say oil-free, and it does not state an oil capacity. The bullets mention an aluminium cylinder head and a cast-iron cylinder, which is not a lubrication method. Sealey’s sheet for this model lists 350 ml of oil, so the manufacturer page describes a lubricated pump. Do not say Amazon confirmed the oil. Sealey’s own compressor guide points oil-free machines at occasional use or at jobs that want cleaner air, and oil-lubricated machines at extensive regular use. That is the maker’s buying split. It is not a measured life in hours for these four pumps. The other decisions, in order, are on the buying guide.
Paint and air lines
Oil mist and water are different contaminants, and a spray gun will show you both. Garden Review’s spraying article describes fish-eye in the paint when oil reaches the gun. That is the failure mode of a lubricated compressor used on a panel without separation. The same article says a water trap is still required on oil-free air, because the tank condenses moisture either way. A coalescing filter is that article’s recommendation when you spray from a lubricated pump. This page does not invent a price or a brand for that filter. If you spray, you budget for the trap, and for separation as well when the pump has a sump.
You can spray from a lubricated compressor when the oil is kept out of the line and the free air delivery covers the gun while the trigger is held. The labelled free-air figures for this set, some of them on maker pages, are about 7 to 9 CFM. A gun that wants more than that will fade, whether the pump is oily or oil-free. Oil-free does not add airflow. It removes one source of fish-eye. It does not remove the water.
If you only nail and inflate tyres, oil in the line is a smaller problem than it is on a clear coat. You still fit a water trap if the tool’s maker asks for dry air, and you still drain the tank. The oil-free SIPs match that lighter pattern with less weekly checking, provided you size the tool on 9 CFM free air delivery and not on an unlabelled headline.
What you maintain
Every receiver in this set collects condensate. Oil-free does not mean dry. After a job you switch off, release the pressure away from your face, and open the drain. The how to use page has that sequence in full. Skipping it on a SIP because the pump has no sump leaves water in a 100 litre steel tank.
The two SIPs have no oil fill and no used oil to dispose of. The TIGREN and, on Sealey’s sheet, the SAC10030VA, need the level checked before you rely on them and at the interval the manual gives. If you tip a splash-lubricated compressor in the boot and then start it, oil can leave the sump and reach the outlet. Stand it level, wait, and read the mark before the motor turns. Used sump oil goes to your council’s household or trade oil route. It does not join the water you drain from the tank.
Pages that quote 2,000 hours or 10,000 hours for oil-free and oil pumps are reporting those articles’ typical figures. Air Supply even flags some of its own hour lines as unconfirmed. None of those lives is in the files for these four models, so this page will not repeat them. You still do not get a duty-cycle percentage for the SIP, the Sealey, or the TIGREN.
When to pick which
Choose an oil-free SIP when you spray, or when you know you will not check a sump, and still check that 9 CFM free air delivery covers the tool. The vertical 05484 is the one that writes the free-air figure on Amazon. The horizontal 05481 is the same lubrication and the same maker free-air figure, at a lower shelf price, with Amazon’s 15 CFM left unused. Which garage that fits is on the best 100 litre air compressor page.
Choose the Sealey or the TIGREN when the compressor will run most days, you will check the oil, and you accept the 97 dB class those manufacturer and listing figures describe. The TIGREN states the lubrication on Amazon. The Sealey states it on the manufacturer sheet, including the 350 ml fill, and states 7 cfm free air delivery there. Between those two, the Amazon page is a safer read on the TIGREN, because you are not reconstructing the oil from a separate sheet. The price difference is small and lives on the main comparison.
Leave both types if the gun’s plate is well above 9 CFM and the trigger will stay open. Lubrication will not close that gap.
Common questions
Which of these four are oil-free?
The SIP Airmate vertical 05484 and the SIP Airmate horizontal 05481. Both listings say oil-free, and SIP’s pages agree. The TIGREN listing says splash lubrication. The Sealey Amazon page does not say, and Sealey’s sheet lists 350 ml of oil, so that model is lubricated on the manufacturer’s evidence.
Is the Sealey oil-lubricated if Amazon does not say?
On Sealey’s own SAC10030VA sheet, yes. The sheet lists 350 ml of oil. The Amazon listing does not confirm oil and does not deny it. Use the sheet for the lubrication, and do not pretend the product page you click on Amazon already told you.
Can I spray with a lubricated compressor?
You can, if oil mist is separated before the gun and the pump’s free air delivery covers the gun. Garden Review describes fish-eye when oil reaches the paint, and it still wants a water trap on oil-free air. A coalescing filter is that source’s requirement for lubricated spraying. The filter is extra. It is not included by the word oil-lubricated on a title.
Does oil-free air still need a water trap?
Yes, whenever the tool or the paint cares about moisture. Compressing air drops water into the tank on an oil-free pump as well. A trap in the line, plus the drain on the receiver, is the moisture control. Oil-free removes the sump. It does not dry the air.
What happens if I tip a splash-lubricated compressor?
Oil can leave the sump and move towards the outlet, and the pump can then be started with the splash level wrong. Stand a TIGREN or a Sealey upright, let the oil settle, and check the mark before you switch on. The oil-free SIPs have no sump to tip, which is one reason people choose them for a car that has to lie the machine down.
What should I buy if I only nail and inflate tyres?
An oil-free SIP, if 9 CFM free air delivery covers the nailer with a margin and you would rather not check oil. You still drain the tank after the job. Move to the Sealey or the TIGREN when the same tools run most days and you will look after a sump. The 97 dB class on those two is a reason to read the noise page before you call that a small step.
Related pages
Sources
Public UK sources and manufacturer pages below. amazon.co.uk listings checked on 20 October 2026.
- HSE INDG178: Written schemes of examination (retrieved 20 October 2026)
- Pressure Systems Safety Regulations 2000, regulation 8 (retrieved 20 October 2026)
- HSE: Noise at work, employers (retrieved 20 October 2026)
- Control of Noise at Work Regulations 2005, regulation 4 (retrieved 20 October 2026)
- GOV.UK: Pressure Equipment (Safety) Regulations 2016 (retrieved 20 October 2026)
- BCAS fact sheet 851 (retrieved 20 October 2026)
- Sealey SAC10030VA product page (retrieved 20 October 2026)
- Sealey guide to compressors (retrieved 20 October 2026)