Zero Breeze Mark 2 Review: Battery-Powered Portable AC Gawk

Push ‘On’ for cool air. That’s it.

This is the key premise of the Zero Breeze Mark 2 battery-operated air conditioner. Since the invention of air conditioning technology, engineers have been trying to figure out how to make a truly portable air conditioner.

No cords. Only batteries. Lightweight but still capable to deliver plenty of cooling power.

That was the desired combination; and the very direction the Mark II went in, as we’ll see in this Zero Breeze Mark 2 review.

zero breeze mark II air conditioner on a table
Zero Breeze Mark 2 is the first cordless battery-powered AC. A truly revolutionary device.

Here’s the deal:

  • According to Statista, more than 40 million Americans went camping in 2018.
  • More than 2 million people own small cabins with no electricity (that can get really hot in the summer).
  • 6.61% of people aged 30-49 own an RV.
  • Pretty everybody would also do well with a personal air conditioner when the heatwave sets in.
camping air conditioner with a battery
Zero Breeze Mark 2 is perfect for camping or RVs.

You can’t install a mini-split unit in a tent. In cabins, no electricity equals no air conditioning. RVs can get very how in the summer.

For all of this, ordinary air conditioners won’t do. It took a big IndieGoGo campaign (grossing over $550,000) to bring us the Zero Breeze Mark 1; the world’s first battery-powered AC. It was a revolution.

But there were also complaints. ‘It’s not powerful enough’. ‘It blows hot air right back in my face’. ‘It takes an hour to drop the temperature by 18°F’.

It’s only understandable that the 1st device of the new cordless AC technology won’t be 100% foolproof. Zero Breeze learned a ton with the Mark 1.

Quick Assessment Of Zero Breeze Mark 2 (Specs-Wise)

That’s why Mark 2 is so tremendous. All the misgivings people had with the Mark 1 were taken into account, improved upon, and today’s assessment of Zero Breeze Mark 2 looks like this:

  • It’s powerful (can produce 2,300 BTU compared to 1,100 BTU Mark 1; the key is the new rotary compressor).
  • It’s dual-hose (one hose for inflow air, second for heated outflow air; Mark 1 was single-hose and blew hot air right in your face).
  • At full cooling speed, it can drop the temperature by 30°F in 10 minutes. That’s just outstanding for a battery-powered air conditioner.

In this Zero Breeze Mark II review, we’ll go through every aspect of the new battery-powered AC. We’ll look into the cooling capacity, battery life, dual-hose tech, energy efficiency rating (EER), and all associated specs.

If you in a hurry, here’s the all-in-all summary:

Zero Breeze Mark 2 is, for lack of a better word, amazing. It’s seamless to use, lightweight, powerful enough for cooling tents, cabins, RVs, even boats. It’s exactly what we hoped it would be.

The challenging part is the price. Mark 2 costs more than $1,000 and, quite frankly, that is quite a lot even for an ordinary air conditioner. However, Mark 2 is as far from the ordinary as possible. It’s revolutionary need tech, and all advanced technology does come at a steeper price point.

It can, however, offer you what no other AC unit can:

  • Completely portable air conditioner (you can literally carry it in your hand).
  • Actually appropriate cooling power.
  • Most importantly, bragging rights. Just look at it; everybody will be jealous that you have it.

All in all, the Zero Breeze Mark 2 is pretty much the best engineered AC unit we ever reviewed. You can check the current price and buy it here (also watch a cool video):

Check Zero Breeze Mark 2 Here

How Does Zero Breeze Mark II Work?

For all intents and purposes, pushing ‘On’ and ‘Off’ may be your only interaction with the Zero Breeze AC. If you look deeper, however, you can see how the whole device works:

Mark 2 operates exactly like a standard portable air conditioner. The only difference is the power source:

  • Standard ACs are powered by the electrical grid.
  • Mark II is powered by a 24V battery.

Like a standard AC, Zero Breeze Mark 2 follows the same refrigeration cycle. The difference is that the compressor, evaporator, expansion valve, and condenser are tightly packed into the 20″L x 10″W x 11″H dimensions of the Mark II:

cycle of how zero breeze mark 2 cools the hot air
Mark 2 utilizes the same regeneration cycle as other AC units to cool the air.

The compressor, obviously, is the key to this process. Mark 2 has the new rotary compressor, an upgrade from the Mark 1 compressor. It’s so impressive that Zero Breeze often uses ‘The Only Rotary Compressor Battery-Powered AC’ in their marketing material.

zero breeze ac unit with rotary compressor, evaporator, expansion valve, condenser, dual hose exhaust and cool air exhaust
Key parts of the Mark 2 portable air conditioner.

In the front: Evaporator, with the cool air exhaust. That exhaust is the source of cool air the Zero Breeze air conditioner produces. With Mark 2, you also get an exhaust hose; you can effectively direct the cool airflow. This is very useful when you’re using it as a personal AC unit.

In the middle: Compressor, the heart of every portable AC unit, together with the expansion valve.

In the back: Condenser, with the dual-hose exhaust. The dual-hose is what you want; one hose to draw in normal-temperature air, and the second one to exhaust the hot air. The hot air exhaust needs to be vented out of the tent, car, RV, boat, etc. You can have the electrical plug and drain there as well.

Specification Rundown

battery powered air conditioner along with specification sheet
Power Source: 24V Lithium-Ion Polymer Battery
Cooling Capacity: 2,300 BTU
EER Rating: 9.6
Power, Voltage, Amps 240W (24V, 10A)
Noise level: 52 dB
Weight: 16.5 lbs


If the condenser is the heart of a portable AC, the battery is undoubtfully the bloodstream.

Mark II comes with a large 24V lithium-ion battery. Mark I’s major drawback was the 12V battery; this is improved in the new Zero Breeze AC by using the 24V voltage.

The battery capacity is 35Ah or 840Wh. The previous model used a 43 Ah or 477 Wh battery.

depiction of battery that powers the zero breeze mark 2 portable ac unit
The upgraded Mark 2 smart battery is the bloodstream that makes Zero Breeze AC viable.

Zero Breeze Mark II has battery has +76% capacity compared to Mark I battery.

In optimum conditions, this is enough to run the battery-operated air conditioner for about 5 hours. Realistically, however, 3 hours is a more appropriate timeframe of how long the battery lasts.

You can recharge it with:

  • Just plugging into a wall socket.
  • Using a car’s cigarette lighter (in-car charging).
  • Even with solar energy (you can connect it to solar output).

All in all, the battery itself is quite miraculous. Having such a great battery is a necessary condition to run any battery-operated AC unit.

Here’s the telling part: If you want to buy just the battery (and you can), it costs $799. That’s quite a lot for a simple battery, right? That’s just an indication that the Zero Breeze Mark 2 battery is not ‘simple’ at all. It’s the key innovation element that makes Mark 2 possible.

Cooling Capacity And Temperature Drop

Of course, an air conditioner, even a battery-powered portable one, is no use if it can’t provide us with a cooling effect.

With Zero Breeze, we need to keep in mind that this is not an AC unit meant to cool down the entire home. Even a small room would be a problem.

However, the 2,300 BTU cooling power the Mark 2 generates (Mark 1 generated only 1,100 BTU), is perfect for smaller places such as:

  • 2-4 person tents (perfect for camping).
  • Cars (especially bigger ones; SUVs and vans).
  • RVs.
  • Boats (not yachts, obviously).

In such small spaces, the Mark 2 works best. In fact, it can even drop the temperature by as much as 30 degrees in 10 minutes. That’s quite an achievement on its own.

camping in nature with a 4 person tent
Zero Breeze comes especially useful on camping trips (during the hot summer nights).

The smaller room air conditioners, for example, have 6,000-8,000 BTU capacity. Compared to that, 2,300 BTU seems quite small.

However, 2,300 BTU is enough to cool down 115 sq ft room (with 8 feet high ceiling). According to an EPA recommendation regarding the capacity of air conditioners, you can cool down almost 1,000 cubic feet of air with the Zero Breeze’s 2,300 BTU capacity.

That’s actually quite a lot of cooling power. Yes, some concerns were with Mark 1 because it had a 1,100 BTU cooling capacity. The upgraded Mark 2 with 2,300 BTU cooling capacity is well-equipped to cool down even bigger spaces.

EER Rating And Power

To produce those 2,300 BTUs, the Mark 2 smart battery has to generate a serious amount of power. 240 Watts, to be exact.

The 24V voltage makes the 240W possible; the Mark 2 top amperage is 10 amps.

The No. 1 factor when deciding which portable air conditioner is the best is its energy-efficiency. In fact, we even made a list of the best portable AC units based on energy-efficiency.

You might be shocked to find out the following:

Mark 2’s EER rating (Energy-Efficiency Rating) is 9.6. That’s an above-average energy-efficiency even for portable air conditioner.

This is a major pro for Zero Breeze and all battery-powered air conditioners. Battery-powered technology allows for high energy-efficiency. There are certain physical limitations to that, and that’s just the reality of all battery-operated AC units.

Nonetheless, it has to be said that in the world of battery-powered units, the Mark 2 has the highest energy-efficiency rating.

Noise Levels And Weight

Imagine you’re camping in Colorado. You’re in nature, maybe you even have to hike to the site where you plan to put up a tent. In this pristine, quiet nature, you want 2 things from your portable AC:

  • A quiet device (you don’t want to listen to it or disturb nature).
  • A lightweight design (carrying it shouldn’t be too hard).

If you are reading a Zero Breeze Mark 2 review, you realize that this battery-powered device is both. The 52 dB level is about the same noise level as your fridge:

decibel scale for mark 2

Keeping the weight down, however, is a more difficult job than keeping the decibel levels down. That’s because you need a battery, and batteries with as much juice as the Mark 2 battery are heavy.

Zero Breeze keeps the Mark 2 lightweight by using lithium-ion batteries. This is usually a smartphone strategy; iPhone, for example, has a lithium-ion battery that can accost to more than 70% weight of the iPhone.

It’s similar to the Mark 2 design. Using lightweight energy, the Zero Breeze engineers managed to create a battery-power AC with 2,300 BTU of power that lasts for up to 5 hours that weighs only 16.5 lbs.

Here’s what 16.5 lbs mean:

  • You can’t carry it for 5 or 10 miles …
  • … but you can easily walk up to a mile with it or easily put it in a car, RV, or boat.

With all these Zero Breeze Mark 2 specifications attested for, let’s summarize the review in a pro-and-con kind of way:

Zero Breeze Mark 2

  • Revolutionary technology: The holy grail of portable air conditioners successfully unlocked
  • Great improvements: 2,300 BTU cooling power, 24V lithium-ion battery
  • Quiet (52 dB) and lightweight (16.5 lbs) – perfect for camping
  • Most energy-efficient battery-operated AC unit (EER rating = 9.6)
  • Amazing design that will earn you all kind of bragging rights
  • It’s pricy due to new technology
  • Can be used only for up to 5 hours before the battery needs to be recharged

Verdict: The 1st Class Battery-Powered AC Is 1st Class

New technology – the 1st class of devices that comes out – usually aren’t brilliant. The same is true for Zero Breeze. Zero Breeze Mark 1, that is.

However, going over the Mark 2 specs, it’s no wonder that this is widely considered the 1st class battery-powered portable AC unit. Specs-wise it’s brilliant, it has a killer design, and, sadly, a killer price as well.

With everything considered, the Mark 2 is the single most brilliant AC unit we have ever reviewed. If you have deep enough pockets, this is exactly the device you have to take for a camping trip.

16 thoughts on “Zero Breeze Mark 2 Review: Battery-Powered Portable AC Gawk”

  1. You have the EER listed wrong on the Mark 2. It is closer to 10 as it delivers 2300 Btu on 200 watts. Dont confuse the the 3.43 Btu/watt physics conversion with mechanical conversion. Also, the ZB2 does not draw 650 watts.

    • Hello D, you are absolutely correct. The cooling capacity of 650W is actually achieved with a cooling-rated input of 240W. Thus the EER rating is 2300 BTU / 240W = 9.6. Thank you for pointing this out, we have corrected the numbers.

    • You can’t connect them; however, you can buy an additional battery, and replace it when the first one is empty.

    • Hello Julio, yes, the Zero Breeze is powered by a battery; you can’t connect it directly to the car. Works a bit like a laptop; you power the battery and the battery powers the laptop. Update: You cannot charge the battery and use it at the same time.

  2. I am ready to order, but can this unit be powered directly from de wall outlet as an alternate power source?

    • Hello Javier, it can be powered directly from the wall outlet. However, while the battery is charging, you can’t use the air conditioner. Only once the battery is full, you disconnect the charging cable and can use the air conditioner.

  3. How long does it take to fully charge the battery using the 12 Volt outlet in my camper? Are there other portable AC units that can be receive charge while in cooling mode?

  4. So then how does the Basic package which they sell (with no battery) work if you need a battery connected for the AC to operate?

    • Hello Jake, you can use the AC as long as you want if it’s plugged into an outlet. With the addition of a battery, you get a portable battery-powered AC; which is, in a sense, the point of Zero Breeze 2.

    • They also sell a 12-24v inverter. This can be used to charge the battery off your 12v system, or alternatively power the AC directly if your 12v battery system is robust enough. I have a 150AH second battery system in my pickup and that’s what i do. Ands it runs all night.

  5. I recently purchased one with the optional 12-24v inverter. I attached an Anderson plug and can run it all night long on my 150AH second battery system, in my overland truck. I’m a heavy vehicle pilot in Western Australia where desert temperatures often reach 48+ degrees Celsius, with a minimum 39 overnight, so this has been a game changer.


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