£250-£500
► Installing a compressed air system inside a workshop is a big commitment that is costly to start with, but can save you money on a range of compatible tools that would otherwise be batteryor mains-powered and often more expensive.
The starting point is to buy a suitable air compressor, which should cost between £200 and £400. In most cases, this will need to be connected to the mains electricity to be able to generate and store compressed air, so that it can be used to power a range of tools. Some compressors only need a standard 13A three-pin plug connection with a 230-volt supply but check before you buy in case you need to upgrade the electrical supply to your garage or workshop to fit a dedicated fusebox.
Check the storage capacity of the air compressor, which is measured in litres. A small capacity of 25 litres for instance, may mean the compressor has to regularly refill itself if you are using an air-fed die grinder or a polisher for a long period of time, resulting in the job stopping and starting. A larger capacity of 100 litres will take longer to fill up, so if you only need some air to check a few tyres, it may take longer to wait for the compressor to be ready than it does to inflate the tyres with a foot pump. If you are routinely using an air compressor, then switching it on at the start of the day shouldn’t present any issues, but remember that the power consumed by an air compressor can make it expensive to run. From the selection we have looked at, most consume 2.2 kilowatts, so if we assume that electricity usage is charged at 50p per kilowatt hour, then such an air compressor will cost £1.10 per hour. That doesn’t mean to say that leaving it switched on will cost nearly £10 for a working day, because the electricity is only used when the compressor needs to fill up its tank.
Other considerations when choosing an air compressor include the number of outlets, which enable you to route pipework and hoses from it to different areas of the workshop. Check that the compressor is supplied with a pressure regulator so you can control how much air is supplied to your tools and also find out how much air pressure can be produced (measured in psi or bar) to ensure it’s suitable f
