Thursday, March 23, 2023


Ask Dave: Can my air conditioner filter out wildfire smoke?

Answers to questions about RV Repair and Maintenance from RV expert Dave Solberg, author of the RV Handbook and the managing editor of the RV Repair Club. This column appears Monday through Saturday in the RV Travel and RV Daily Tips newsletters. (Sign up for an email reminder for each new issue if you do not already receive one.) Today Dave discusses wildfire smoke and RV air conditioners.

Dear Dave,
We are planning to replace the air conditioner on our class B Sprinter Leisure Travel van. My question is: To what extent will an RV air conditioner help to filter out wildfire smoke? It seems to me that the air conditioner would need to be able to have a recirculation mode and a fresh air intake mode. Is there a clear choice out there for one that does a better job than others in keeping the interior relatively smoke-free? Thank you so much for your help with this! —Leslie

Dear Leslie,
Thanks for the question as this is a fairly big issue these days with all the wildfires around the country. We even see the effects here in flatland Iowa at times.

How an air conditioner works

Your rooftop air conditioner will do a slight amount of filtering depending on the type of unit you have. Most rigs come with either Dometic or Coleman units. Lower price models have the vent and fan directly at the air conditioner and others have ducted vents in the ceiling. Both have an interior air return that draws warm moist air from the upper portion of the rig into the unit and through the evaporator fins. This air return has a filter in both the direct air and ducted type of models.

As you can see from the photo, the filter is a very thin piece of cell foam and designed more for keeping out dust and pet hair than actually filtering smells. Some of the ducted roof air conditioner models have a little better filter. However, it’s nothing like a residential filter you would see in a furnace/air conditioner model, and nowhere near a HEPA-type filter. You don’t want to replace the flimsy filter with something heavier as it will reduce airflow to the unit and eventually cause the motor and compressor to fail.

So what should you do?

I would suggest getting an air purifier that you can put anywhere in your rig. They are very compact and don’t draw many amps. So you should be able to run the roof air conditioner and the purifier at the same time. I would recommend going with a unit that utilizes charcoal. These models seem to have the best reviews but do cost a little more money. The unit I have is a Honeywell that I got at an auction a thousand years ago and it works great. It’s just a little heavy and draws about 8 amps, so I have to do some energy management. One that seems to be very popular is this one made by Blueair.

Read more from Dave here

Dave Solberg worked at Winnebago for 15 years developing the dealer training program, as marketing manager, and conducting shows. As the owner of Passport Media Creations, Dave has developed several RV dealer training programs, the RV Safety Training program for The Recreation Vehicle Safety and Education Foundation, and the accredited RV Driving Safety program being conducted at rallies and shows around the country. Dave is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club.


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1 year ago

I would buy an air purifier that produces ozone that will help neutralize the smoke and pollen in the air. Also, one that causes the particles in the air to fall to the floor so you vacuum them up.

Norman Worthington
1 year ago
Reply to  rvgrandma

We purchased 2 Honeywell air purifiers for our trailer. Home Depot has them with a 99.7% HEPA filter. They are both the same size filtering 500cf/minute. We live in the smoke, i have asthma as well as lung cancer. Between the two of these…I don’t deal with any smoke in the trailer (41′ fifth), one in front and one in back. They say to change filters every 6 months…I find it necessary to change every 2 months due to the dirt (& I mean dirty!) air. Check the old one vs a new filter and you’ll see the difference! The filters can be expensive but shop around.

1 year ago

last year in Oregon we were in wildfire smoke for almost 10 days. I went to WalMart and bought the best Filtrete carbon air filter they had. I cut it up to fit over the intakes on my ducted AC system and then taped them in place. After 10 days they were covered in particulate and really helped with the smoke smell in the coach.

1 year ago

I have disliked Dave’s answers to a lot of questions posed in the past, here I also think he did not answer properly. Why not mention the typical rooftop A/C unit does NOT draw in outside air, but recirculates what is already inside. If you smell smoke, then you have to deal with it as he mentions as it leaked in elsewhere.

1 year ago

On AC article your emphasis is on the filter. However shouldnt the question be why is the ac drawing from outside vs inside???

Bob p
1 year ago
Reply to  Lewis

Rv a/c does not draw outside air in, it is a total recirculating system, if you are getting smoke inside you need to seal your rv .

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