AirGradient Open Air Max Released

Ethan · April 18, 2025, 6:32am

A few years ago, I had the chance to try the AirGradient ONE (indoor monitor) and Open Air (outdoor monitor) and I quickly became a fan of the devices. While I liked the devices themselves (especially the open source element of them), I appreciated the company’s mission even more. Not only are they committed to transparency and open source, but they also really focus on community. In fact, they impressed me so much with these values that after trying the devices myself, I decided to begin working with the company.

So, please consider this a disclaimer. I do now work with AirGradient, but I only accepted working with them on the premise that I’m allowed to stay transparent and honest - something which they were more than happy to accomodate and even encourage.

For this reason (and because I’m looking forward to the new improvements), I am excited to discuss the upcoming Open Air Max. This new air quality monitor is designed to be a ‘professional’ alternative to the original Open Air. How is it more ‘professional’ you may ask? Well, here are a few changes:

Added an additional Plantower PMS5003T particle sensor for redundancy (with the original Open Air, you had to choose between EITHER 2x Plantower sensors, or 1x Plantower sensor and 1x CO2 sensor).
Comes with an included solar panel.
Comes with cellular connectivity (included SIM).
More accurate temperature/RH readings due to an external temperature probe and SHT40 module being used.

You can read more about the Open Air Max here: The First Professional-Grade, Affordable Air Quality Monitor

Of course, this means the monitor is more expensive - the expected price is $395 (USD). However, this makes it only 25% or less more expensive than some other outdoor options but with a few advantages. There will also be a second monitor with NO2 and O3 sensors available, but this will cost significantly more at $990. While some consumers may be interested in this device, it will mostly be focused on more professional markets.

The two monitors are set to be released in the next few months and I just recently received one device to test myself. While it’s still a pre-production model, I’m excited to share my thoughts here.

My Open Air Max is currently deployed in Hanoi, which, unfortunately, is one of the most polluted cities in the world as of the time of writing. It will be a good test for the device, and should be well-suited to the solar update.

I will continue to share my thoughts and experiences with the device in this thread until my review (or perhaps just an article - I’m still trying to figure out how to best introduce this device while trying to remain as unbiased as possible) is complete. If you have any questions, please don’t hesitate to ask here!

Ethan · April 28, 2025, 7:37am

I’ve had my AirGradient Open Air Max set up for around one week now and I have a few more thoughts and findings to share.

I opted to change the batteries on my Max and went out to purchase a set of three 18650 batteries. I opted for 3x Panasonic 3500mAh batteries as their price was reasonable and Panasonic is generally a reputable brand. Unfortunately, after getting them home, I realised that the Open Air Max only has space for unprotected 18650 batteries. While the protected 18650s can be forced into the battery slot, I would highly recommend against this due to the fact that you could break the battery holder or even the mainboard (to which the battery holder is attached).

I don’t have much experience with 18650 batteries, and for anyone else in the same boat, this is something to keep in mind. Some 18650s are classed as ‘protected’, meaning they have a built-in circuit to protect from dangers such as overheating and short circuiting. Unfortunately, these circuits add a few millimetres to the length of the batteries, and mean that they may not fit into some devices (like the Open Air Max).

After this finding, I went out to purchase some unprotected 18650s and I found these to work well. They’re still 3500mAh, giving the device around 10,000mAh of total capacity - the same capacity as most portable batteries. I believe this is enough capacity for 3-5 days of runtime without sunlight (from a full charge).

I am testing a beta device without any power-saving improvements (compared to the original Open Air which is designed to be powered via a USB cable). The final product will likely have 4-5x the battery life of the device I am testing. This is not a final product, so please keep this in mind!

Unfortunately, as can be seen by my monitor’s reporting above, I haven’t been able to get the device powered very often due to a lack of sunlight. Despite being in Vietnam, which is generally quite sunny, I’ve had trouble powering the device due to rainy and overcast days (and days of very heavy air pollution) and the position the monitor is in. Since we’re currently staying in an apartment, I’ve faced the device towards the morning sun. However, it doesn’t receive any sun after 1-2 pm. As you can see, the sunlight is often enough to power the device temporarily and to charge the batteries for a few hours of runtime, but it’s far from enough to consistently charge the device.

Therefore, I believe that a second solar panel may be needed for quite a few people installing these. If you can place the device in a garden or somewhere where it can have more than a few hours of sun, or if you live in an area that gets regular (strong) sunlight, this shouldn’t be an issue. However, I’ll definitely need to look into relocating my monitor.

As you can see, the weather hasn’t exactly been conducive to running a solar-powered air quality monitor!

Also, one other note that I forgot in my first post: the AirGradient Max uses the Senseair Sunlight instead of the S8/S88 found in the other AirGradient monitors. While this is a more expensive sensor, it has very similar accuracy to the S8/S88 with the advantage of being vastly more power efficient. Just a minor change compared to the original Open Air that I forgot to mention!

Ethan · May 14, 2025, 10:03am

The Open Air Max has now been fully announced and released and you can find it here:

With O3 and NO2:

Without (the model that I’ve been testing):

Right now these are still pre-orders for June/July., but you can now purchase the device if interested.