Every air conditioning system has a filter designed to keep dust from entering both your home, and the system. A clean air filter is vital to keeping your system in good condition, helping it last longer, and helping your air stay cleaner. What happens if you don’t have a filter? Can you still run it while you run to the store for a new one?

The good news is that yes you can run the AC while you nip out to the store. This doesn’t mean you can run the AC permanently without a filter and just sweep your home more often. An air conditioner can run for no more than 6-8 hours without a filter and not become damaged. Anymore than this, and you could be setting up your system for serious damage.

How air filters work

In order for your HVAC system to keep your home cool, it takes warm air in through the supply vent. The unfiltered air is then drawn up using fans, and pushed through the air filter. The air filter traps dust and other contaminants that will both pollute your home and damage the system. The air is then cooled via refrigerants that release hot air outside the home, and the cooled, cleaned air is delivered to you through the registers.

This system works well, but a dirty or missing filter can cause problems for you and your air conditioner. Here’s what can happen if you run the AC without a filter for too long.

It can damage your machine

The air filter isn’t just there for you to breathe easier. It’s also there to keep dust out of your HVAC, which can become damaged if it is forced to run with dust clogging up its machinery. Among other things, this can lead to a damaged compressor, frozen evaporator coils, or even actual damage to the coils.

Replacing these parts can be very expensive. A damaged compressor can cost as much as $3,500 to replace, hurting you a lot more than the price of an air filter would have. Even if the compressor or coils don’t need replaced, damage to the air conditioner can typically leads to other problems.

Common problems with the air conditioner include increased electric bills, the AC not cooling the home well, or even not cooling the home at all.

It leads to poor air quality in the home

This is perhaps a bit more obvious, but without the air filter to filter the dust out, your AC will now be spewing dust all over your home instead. We spend 90% of our time indoors, and air quality can have a very big impact on the quality of your health.

Dust going through your system also means more dust entering your electronics and potentially damaging them, settling on your furniture, and a lot more cleaning.