EcoFlow’s Wave portable AC and Delta Pro generator: How to stay cool through heatwave power outages

The EcoFlow Wave is a 38.5 lbs portable air conditioner. A real one. We’re not talking about one of those cheapo devices where you throw in a few ice cubes, and a fan blows air over melted ice water. We’re talking about a device that uses electrical power (more about that in a minute) to reduce the air’s temperature substantially.

First impressions

Let’s start with a first impression. I pulled the machine out of its shipping carton, set it up on one of my tables in my workshop, and plugged it in. I hit the power button, and within about 30 seconds, it was blowing air in my face that was so cold that I was genuinely chilled.

To be clear, air cooling isn’t just about whether cold air blows out of the front of the machine.

There’s a small matter of CFM (cubic feet per minute) or, as EcoFlow and the rest of the world puts it, cubic meters per hour. That’s how much air can actually flow through the thing, which determines how large a space can be cooled. Another handy term is ACH, meaning air changes per hour, or how often all the air in a space can be replaced.

So, let’s say you need to cool a one thousand square foot area with eight-foot high ceilings, and you want four air changes per hour. Using the handy calculator at LearnMetrics.com, you need a CFM of 553. Using the calculator on ConvertUnits.com, that’s 939 cubic meters per hour.

And that, in a bit of arcane math, tells you all you need to know about the limits of the EcoFlow Wave. It can do 290 cubic meters per hour or about a third of what’s needed to cool a thousand-foot space.

But do we really expect a 38 lbs device to cool a space the size of a two-bedroom apartment? No, that wouldn’t be fair or realistic. My family room is roughly 18 feet by 16 feet, or 288 square feet and has a nine-foot ceiling. So, let’s use our calculator on that. We need 173 CFM or 293 cubic meters per hour to do four air exchanges per hour.

Since the EcoFlow Wave handles 290 cubic meters per hour, it should be able to nicely cool a room the size of my family room, a bedroom that isn’t too huge, a small home office, or any other small-to-medium sized room.

Interestingly, EcoFlow doesn’t pitch the Wave as a room AC unit. Instead, they recommend using it in an RV or camper or in a tent. My inner Boy Scout shudders at the idea of using an AC unit in a tent, but then again, my inner Boy Scout never had wireless broadband either. Since my inner Boy Scout long ago became my outer adult, and my outer adult prefers comfort, well, I’m just the sort of person who would pack something like the Wave to go on a camping trip. In fact, something like this would probably make the difference between camping and (shudder) glamping.

Cooling for emergency preparedness

But I’m actually more interested in the Wave for emergency preparedness. Last year, a heat wave pushed temperatures north of 110°F here in Oregon. This area rarely goes above 90. But with forest fires and power failures, the idea of spending a couple of days in 110-degree heat is not at all appealing.

The Wave could make living through such an event far more tolerable. The unit can be equipped with an optional add-on battery (that’s another 18 lbs). With that battery, the unit will run for about two hours, set at the lowest temperature (60.8°F or 16°C). You can boost that up to three hours if you’re willing to turn the airflow down and set its temperature all the way up to 78.8°F (or 26°C).

For emergency management, this is pretty good. Excluding major events (like the Texas freeze or hurricanes, or forest fires), the average power outage in the United States lasts about two hours, according to the US Energy Information Administration. If you set the temperature of the Wave to the middle of its temperature setting and keep that battery charged, you should be able to weather most outages.

On the other hand, the length of the average outage, when major events are factored in, has fluctuated between about four hours (prior to 2017) and as much as eight hours (since 2018). This is where the other very heavy box EcoFlow submitted for review; the EcoFlow Delta Pro, comes in.

The EcoFlow Delta Pro battery generator

The Delta Pro is the big brother of the Delta Max battery generator I spotlighted last year. In addition to being twice the weight (99 lbs instead of 48 lbs), the Delta Pro provides roughly double the capacity of the Delta Max.

Crazy-making naming conventions alert…

If you’ve been following Apple’s naming conventions for its processors and devices, Max is more max than Pro. For example, the AirPods Pro are still earbuds, while the AirPods Max is twice the price of over-the-ear cans.

The M1 Max processor has twice the GPUs with twice the maximum memory and memory bandwidth as compared to the M1 Pro. But… with EcoFlow, Max isn’t max. With EcoFlow, Max is the smaller one, and Pro is the bigger one. It’s enough to give you a headache, and I have to keep track of this stuff for a living. Ugh.

Now, back to our regularly scheduled review (just remember that this time Pro is bigger)…

The Delta Pro battery generator provides 3600W of AC output, and we can put that to use with the EcoFlow Wave to keep it running all night.

Without the Wave’s own battery, an 80% charged Delta Pro can provide four hours of power when running on maximum cool (60.8°F or 16°C). If you set the Wave at its lowest cooling level (i.e., not cooling as much, set to 78.8°F or 26°C), the Delta Pro can go for a full 12 hours on an 80% charge. Figure about half that time if you’re using the smaller Delta Max generator.

If you have both the Delta Pro and the Wave battery, you can combine the Wave’s battery to give you six hours with cooling set to the absolute max and 15 hours if you keep cooling at a bit under 80°F.

These are not inexpensive devices. The EcoFlow Wave is $1,199, with the battery being an extra cost item. The Delta Pro is $3,599 and the Delta Max is $2,099. Solar panels, which we’ll discuss next, are also extra cost items.

To be clear, the Delta generators aren’t just useful for powering your portable air conditioner. Each has about 15 sockets and can charge all sorts of items, from your phone to your freezer (so you don’t lose expensive food in an outage) to your coffee maker (so you can be human in an outage).

One particularly interesting use I’ve been hearing about lately is that contractors are taking them along to their job sites to power tools like table and miter saws or charge the batteries for their cordless tools. The Delta generators are lightweight compared to gas-powered generators. If you’re working in a shed or a building not yet connected to the grid, you can get a lot of work done where previously you’d need wall power.

Charging from the wall or from the sun

Both the Delta Pro and the EcoFlow Wave can be charged from EcoFlow’s solar panels. EcoFlow sent me panels to test, but living in Oregon, the sun tends to hide behind rain and overcast conditions. I will do a solar panel test in the future when the sun is more cooperative.

The key takeaway, though, is that you can charge both of these devices either through traditional wall power or by capturing the sun’s rays. Jason Perlow has done some testing of solar panels in sunny Florida, so make sure you read his coverage.

App setup

The app setup was… amazing. I’ve never had an IoT device setup easier than the EcoFlow devices.

I loaded the app on my phone, and I was fully prepared to go through the whole process of entering my serial number, registering, specifying model, and all of that — but then I looked at my screen and saw both the Delta Pro and the EcoFlow Wave indicated as icons.

They connected automatically via Bluetooth and just worked.

Physics of cooling

The EcoFlow Wave, when pushing air at top speed, can be noisy. It’s a reasonably fair trade-off for coolness, but it’s something to keep in mind.

Another thing to keep in mind is that it is subject to the laws of physics, particularly the law of conservation of energy. Essentially, the total energy of an isolated system must remain constant.

How does this work in air conditioning? Well, to cool a room down, you’re removing heat. By the law of conservation of energy, that heat doesn’t just vanish. It has to go somewhere. Most air conditioners bring in room air and push out both hot air as exhaust and cool air as comfort cooling.

So, if you set up the EcoFlow Wave in a room and turn it on, the front of the machine will blast cold air. But the back of the machine will blast hot air with temperatures in excess of 100°F. If you’re standing in front of the Wave, that might not be too much of a problem, but you’re not going to be able to cool an entire room because the hot air is going back into the room.

EcoFlow solved this by including flexible 4-inch exhaust tubing. You attach that to the back of the Wave and drop the tube outside a window, venting the hot air outside. Of course, there’s a problem with this, in that most windows don’t have convenient 4-inch holes. You’ll need to get some sort of bracket vent, like the one I use to exhaust my laser cutter or hack something together out of plywood and duct tape.

Another factor is condensation. Most of the air we breathe contains water in gaseous form. As the water molecules cool, they slow down, and that slowing down causes the gaseous water to solidify into water droplets. Most air conditioners have to manage drainage so that as the water condenses from the cold, it has someplace to go.

EcoFlow says that it has come up with a no-condensation cooling system (but does provide a drainage hose in case your space is particularly humid). The company says that the heating element in the Wave evaporates water before it has a chance to condense.

Regardless of air moisture content, if I were planning on placing the Wave on a hardwood floor, I’d still put something waterproof underneath, just in case.

Final thoughts

It’s really nice to see innovative portable air cooling units with rechargeable batteries and solar options. While this gear could make RVing a joy on hot nights away from the power grid, it also has huge potential to help you get through power outages and the inevitable heat wave.

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