How to clean your car’s HVAC and interior to keep away mold!

As I write this, we’re coming into another air conditioning season in the southeast US, which means air conditioning not only at home, but in your car.  Vehicles are so susceptible to mold ingress, because of where we drive (through dust, mud, and pollen), where they are parked (whether it’s outdoors in blazing hot driveways or indoors in damp garages), and their design (carpeting everywhere!  Air conditioning filters that hardly ever get changed!)  Whether or not you smell that musty moldy smell when you get in the car or turn on the A/C, now is the time to deal with mold before it deals with you.

Just like your home’s HVAC system, it’s important to maintain your car’s HVAC system for your health.  Here is a great article on cleaning the evaporator coils in your car.  This method is very non-invasive, and includes tips if any mold smells do not go away.   The antimicrobial agent they recommend is called Nutribiotic. Nutribiotic is a grapefruit seed extract (GSE) which is highly acidic and microbial at full concentration (be very careful mixing and using it!) but can be diluted to use as a coil cleaner.  Please note that using a commercial coil cleaner is not recommended because the residues can add many VOCs to the air you breathe, which may not go away for some time!  

When cleaning the HVAC system, be sure to replace the cabin air filter, which keeps a lot of dust and pollen out of the car.   Some older models don’t have a cabin air filter (commonly in pre-1996 vehicles and even as late as my 1999 Suburban), in which case you can even get creative and make one!  (For those of us who aren’t super-familiar with cars, note that the cabin air filter is different from the air intake filter.  The first one filters the air conditioning system, while the second one filters the air going into the engine, which is not what we’re talking about here.)

We’re working from top to bottom, and next come the seats.  Cloth seats will probably hold more dust and mold than vinyl or leather seats, because they are permeable and allow liquids and dust to pass through and stay in the foam beneath.  With any liquid cleaner you use, you should definitely use an extractor.  Whether it’s a carpet cleaning machine, or a simple wet-dry vacuum, you need a way to get the liquid back out of the carpet, or mold can set in after you just cleaned it!  If you live in a populated area, either one (carpet cleaner or wet/dry vac) should be available on places like Facebook marketplace for about $40. One more tip: only clean your car’s upholstery and carpet on a bright sunny day outside, or in a heated garage!  You’ll need the benefit of ventilation and heat to get the fibers completely dry. 

Now, what to use as a cleaner?  One of the most popular carpet cleaners in the supermarket is Resolve, and RESOLVE Professional Spot and Stain Carpet Cleaner earned an “F” grade from the Environmental Working Group (EWG), an organization dedicated to evaluating the safety of consumer products!  There is a better way. 

  • Our new Total Clean spray is like a Swiss Army knife that cleans solid and porous surfaces well!  Use it at normal strength (1:7 parts concentrate to water) for non-stained carpet and upholstery, or double or triple strength (1:3 or 1:1 parts concentrate to water) for stains.  Normal strength TotalClean is great for vinyl and leather surfaces, as well as any hard surfaces such as dashboards, gauges and steering wheels, being sure to wipe it away quickly with a clean dry towel. 
  • Most “homemade” carpet cleaners call for a mixture of vinegar, baking soda and water in various proportions.  I really like this one, which adds in (non-toxic) dish soap.  If you are using a simple wet-dry vacuum, use the cleaner in a spray bottle, agitate any problem areas or stains with a scrub brush, and follow with the vacuum to get the liquid out.  If you are using the carpet cleaner machine, follow manufacturer’s directions.  In either case, make sure to use the liquid sparingly!  Too much liquid going in (especially on cushioned areas) increases the likelihood that it will not all come out with the vacuum.  I advise taking out a car mat to clean first, to assess the suction power of your vacuum or cleaning machine.  After several vacuum passes, the carpet should only feel damp, not soaking wet.  (From experience, I once wetted down a large area of my sofa before discovering that the suction of the cleaning machine attachment wasn’t working!  I was blessed to have a wet-dry vac available as a backup). 

Unless you have those nifty molded floor mats that capture the dirt and water that you track in, there is going to be dirt and there is going to be mold in the floor of your car.  Mold thrives in dirt and moisture.  Even if the carpet is not stained, it’s a great idea to clean the carpet at least once a year to remove mold and dirt.

Now that you’ve removed the sources of mold in your car, you can add some non-toxic scents back into it.  Here is a video with 6 different ways to make non-toxic car air fresheners using essential oils and different items to hold the scent. (The speaker may be a bit difficult to understand, but the sachets she mentioned are muslin drawstring bags and the last item she sprayed on was wool felt–a very natural, absorbent material).  If you don’t have the time to make your own, just order some vent clips or auto stix from Enviroscents, a company that does not use toxic materials in any of their products.

Ahhh!  It may be a bit of work to achieve, but who doesn’t like the smell of a clean, fresh car?  For as much time as we spend in them, your health is worth the effort!