We’ve used the Zero Breeze Mark 2 for a few years now. And we absolutely love it.
It’s kept us cool all through the Americas, from sweltering 40 degree days to sticky 30 degree nights.
So when the new Mark 3 dropped, we had to try it.
So the guys at Zero Breeze sent us this unit to do a proper, real-life Mark 3 review.
Which for us means, this review is not about comparing tech specs on paper.
Though we’ll cover those too. It’s more about how the Mark 3 has fit into our actual life.
How it keeps our bedroom cool. How it’s handling humid UK nights. And how it's earned a place in our current boat setup.
Spoiler alert … We’re impressed.
But more on that shortly. First, let’s start with …
We first installed the Mark 2 in our camper back in 2022 (you can read more about that setup here). It went with us through North America, Central America and even down into South America.
It survived desert heat, jungle humidity and everything in between.
At the time, we knew we had found something special. It didn’t try to be a whole-house solution. It just made sleeping at night much more comfortable. And for us, that’s the biggest win.
Now that we live on a boat, we took what we learned from vanlife and adapted it. Our power setup is different. But during the hottest and sunniest days, our 2 x 300ah Lithium batteries are maxed out anyway.
Which means we can run the AC for hours in sleep mode with no issue, knowing the batteries will top up again the next day.
Often though, we just keep the Zero Breeze battery plugged in while it's running. That way, if we forget to turn it off, it just drains that battery and shuts itself off. Then we recharge again during the day.
Simple.
In the mornings, if it’s a sticky/humid one I often get up early and switch it on before Cazzy wakes. It cools the room in minutes. She stays asleep. I stay popular.
For more of an idea of how we get power in our boat, you can read about our houseboat off-grid electrical system here.
So what exactly are you getting with the Mark 3?
It’s important to clarify the exact spec of the unit, and understand just how much is packed into this relatively small unit.
Here’s a full breakdown of the important stuff. No fluff.
Bottom line. It's compact. It’s powerful. And it’s built to slot neatly into off-grid setups like vans, boats or cabins.
So here’s the deal. On our van setup, we had to drill right through the side. Exhaust vents out. Cool air in. All neat and tidy. A bit of a mission. But worth it. Here is how that looked:
On the boat, things were a little easier. And honestly, I’m buzzing with how well it’s worked out.
We decided early on that we didn’t need to cool the whole boat. Just the bedroom. That’s where it gets muggy. That’s where we sleep. And that’s where comfort matters most.
Luckily, we didn’t need to drill massive holes through the hull like we did with our van install. Instead, I repurposed an old bookshelf just outside the bedroom. Lowered the shelf a bit and slotted the unit in. It’s a tight fit, but it works. I used a bungee cord to stop it slipping, though a proper bracket or deeper shelf would be better long term.
Then I drilled two small holes through the wall into the bedroom. These are for the cold air in and return airflow. That’s all it needs. The unit pulls warm air from the room, cools it, and blows it back in. The hot exhaust vents out into the hallway where the unit sits. So no holes in the hull. No need to run ducting out the boat.
Important note: There’s a drain tube that comes out the back, and it needs to point downwards. Otherwise water builds up. We’ve got a tub underneath catching the runoff. Not elegant. But it works. And you’d be surprised how much water it pulls out. A few litres after 4 or 5 hours. Easily as much as a regular dehumidifier.
For long-term use, you could absolutely add a skin fitting and let the water drain straight out the side of the boat. But for now, we’re keeping things low-impact. The fewer holes the better.
It’s worth noting how the Zero Breeze Mark 3 actually works. It pulls air in from the room you want to cool. Conditions it, then pumps cool air back in. So you need two ducts going into that space. The rear vents kick out warm air and don’t need to go into the room.
You can also flip the system around so that it operates in heating mode. Haven’t tested that much yet. But good to have the option.
Here’s the big question … Does it work?!
Yes. Absolutely. It cools the room fast. Sleep mode keeps it going for hours with barely any power drain. And on those hot, sticky UK nights — where it’s not the temperature, it’s the humidity — it’s a total game-changer.
What we’ve found most useful is the routine. I’ll often get up a bit before Cazz, switch it on in sleep mode, and let the room cool down. She can keep snoozing in peace. Meanwhile, the rest of the boat stays humid. But not the bedroom.
We’ve left the unit running for several hours on end. No issues. Especially since our solar setup is maxing out in summer anyway. We keep the battery plugged in so it can drain itself if needed. Then just recharge again the next day. Or I will just plug it straight into the mains and run it that way.
Connecting between the battery and the mains is simple as it’s all the same charger, you just need to switch over the rear adaptor.
The Mark 3 has been a reliable daily-use unit. It doesn’t try to cool massive spaces. And that’s fine. That’s not what it’s for.
It’s made for bedrooms, bunks, cabins, or small offices. Any small enclosed space where comfort really matters.
And in that space, it performs brilliantly.
We’re actually in the process of looking to buy a house, so naturally the bedroom is about 3-4 times larger than the one in our boat. I’m (geekily) excited to see how the unit works in cooling that space.
So on paper, the Mark 3 smashes the Mark 2. Bigger cooling output. More efficient. Better battery. Smarter vent system. And a proper control screen.
Cooling Capacity:
Power Consumption:
Operating Modes:
Battery Capacity:
Runtime on battery:
Battery Functionality:
Ventilation System:
Noise Level:
Weight:
Dimensions:
Drainage:
Dehumidifying:
Refrigerant:
Port Design:
Price & Value
Portability? About the same. Still a chunky bit of kit. You’re not throwing this in a beach bag and lugging it to the coast. That’s not what it’s for. But both are surprisingly compact for what they offer. Easy enough to slot into a van build or boat shelf.
Cooling power? Definitely stronger. The Mark 3 cools faster and harder. Especially noticeable when it’s proper muggy. Like UK summer muggy. You turn it on, and within five minutes, the air actually feels breathable again.
Battery life? Mark 3 is better. More efficient and better options for stacking or expanding battery use. Especially good for off-grid people. Like us.
Vents and connectors? You can tell Zero Breeze listened to feedback. The ducts are different shapes and sizes now. Not just cookie-cutter tubes. You can see some proper engineering has gone into air flow and pressure.
Control screen? Looks sleek. Feels modern. But to be fair, I had no real issue with the Mark 2’s simpler setup. This one is just more polished.
So do you need to upgrade?
If you’re cooling a bigger space, want longer battery life or just want the latest and best, then yeah — the Mark 3 wins hands down.
But our Mark 2 still works perfectly. Three years on. No plans to bin it. It’s staying in our van setup for the long run.
Absolutely.
If you’re off-grid and serious about comfort, this is one of the best portable cooling systems out there. It’s not cheap. But it’s powerful. Smart. And genuinely useful.
The Mark 3 is ideal if:
The Mark 2 is still solid if:
Either way, Zero Breeze clearly listens to its users. You can see the progress between versions. And as someone who’s used both for years, I’ve got nothing but good things to say.
That’s about it really!
Have you tried the Mark 2 or Mark 3?
Got your own setup or installation hack?
I’d love to hear how you’re using it.
Or if you’ve still got questions I haven’t answered, drop them in the comments below. I’ll get back to you when I can.
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