Q&A for How to Choose an Air Compressor

When determining the appropriate gallon capacity for an air compressor, consider your intended use. For home use, opt for a one- to two-gallon compressor available at stores like Lowe's or AutoZone. These are suitable for quarter-inch or half-inch drive air tools. Conversely, for mobile applications such as service trucks requiring ample compressed air, aim for a minimum of a 10-gallon capacity compressor. This larger capacity unit offers greater capability, albeit at a higher cost.

If you are running a nail gun or, more importantly, an automotive paint gun, you want to be able to control the air pressure. On a nail gun, too little pressure and the nail wont drive in. Too much pressure, and it will fly clear through the material you are trying to nail.

The tank is full. Once the compressor reaches it's PSI capability in the tank, it shuts off as it is no longer needed

10 gallon. Then, blow out zone by zone, two or three times for a short amount of time (because of heat build-up in dry pipes). Use about 60 to 70psi pressure only to be safe and avoid damaging the sprinkler system.

That depends. The tools you are using should read out the necessary pressure you need to be able to run. The larger tank capacity you have, the less amount of time the pump is running.

It all depends on what you want to do with it. You will of course need a hose, if you are blowing dust etc. You will need an air blowing chuck, to pump up tires you will need some sort of tire chuck.

This depends on what kind of material you are sanding. If you are building furniture, you probably want a 5" orbital sander. If you are sanding a floor, you probably want something significantly bigger. If you are doing automotive body work, you will want a range of sizes to be able to get into the contour bends of the cars body lines.

Using any air tool, more than 26 gallons (100 liters) and a belt driven 3hp compressor should do the job.

A five ozone style compressor with 3x insulation and a large exit tube.

You don't calculate them at all. Those are specifications provided by the manufacturer. If you are doing a repair, replace damaged parts with like parts of the same specs. Do NOT DIY repair a tank by welding it, the risk for rupture and harm to persons nearby is too great.

Bike frames do not use compressed air. If you meant you want to mount a 12V compressor on a motorcycle, measure the available space, although it is generally ill-advised to operate a motorcycle with tires that leak, so you would not want to be on the road with a low tire inflation. Never have a situation where you are low and would inflate while riding.

Nailers don't use a lot; it depends on the amount you are going to use them. For DIY light use, a 750W (1 HP), 25-liter compressor will be fine. If you are a serious user, then get something at least twice the size. I use a 500W, 6-liter compressor with a framing nailer when I want something very portable, but I do end up waiting for it to catch up sometimes.

If you are just topping up your car from time to time, then almost any compressor will do it, from the tiny 12-volt electric tire inflators upward. If you want to fill tires in a garage, then I'd say at least about 1500W (2 HP), 50 liter, 110 psi. If you're a tire merchant and are filling tires all day, then you will need something a good bit larger.

That is the flow rate with no impedance to airflow (straight out of the compressor, no restrictions, no tool being powered). It is mostly a useless number unless your primary use is inflating things with very low pressure, like an air mattress or inflatable pool/toy/etc. Instead, consider the CFM at the PSI your most demanding tool, or combination of tools used simultaneously will need.