Is it ok to blow out an air filter?

In short, no.

Here’s why:

The filter medium (material) used in most construction air filters is specialist media paper or synthetic materials. The intake air flows through it while the dust and debris get caught in the fine pores of the medium. As the dirt gets caught in the paper, the airflow becomes reduced and with it, the engine performance also drops. That’s why most machines require air filters to be changed regularly, typically manufacturers recommend a 500 hour service change although in reality if an engine is operating in extreme environments it could need changing more frequently.

Instead of replacing the filter, some people look towards blowing out the dirt. They see it as a way to delay replacing the filter to save money. But does it?

Blowing out an air filter

Blowing out an air filter is usually done with a high-pressure air stream, like a compressor. 

But, it doesn’t actually take that much dirt out. We tested a dirty air filter from a generator. Watch it in the video below.

One of the main issues with blowing out an air filter is the potential danger to your health. How do we know what harmful debris is trapped in the air filter? If we blow them out, we set them free and back into the air, making the air dangerous to breathe.

Another issue is that the purpose and design of quality filter media means that it works to trap the dust. Blowing or attempting to force it to work in reverse causes irreparable damage to the media, effectively allowing larger dust particles to flow back through the filter. When the machine is in normal operation, these particles get through and into the engine, causing costly damage.

In normal operation, an air filter will “self-clean” by the natural backflow of pressure from the engine on shutdown. This allows any surface dirt to disperse inside the air filter housing and in many instances can be emptied via the dust valve on the housing (see pic below). 

All in all, blowing out an air filter is a short-term fix we do not recommend.