Climate Control

Mistbox Review: Does this Smart HVAC Device Really Save Costs?

(Last Updated On: October 31, 2016)

Summertime makes your air conditioner work double time and, as a result, people often get stressed about their electricity costs doubling up, too.

This is the problem that the Mistbox tries to solve. 

The Mistbox can save anywhere from 20% to 40% of your cooling cost while also ensuring that you do not waste water.  Mistbox sells for about $400 as of this writing (price check here), but is it worth it?

Mistbox Design

The Mistbox unit is made of plastic.  It features an LCD screen that has three soft touch buttons, a water filter, water intake connector, and a Wi-Fi antenna.  The power port is located at the back of the unit.

The Mistbox is powered by the sun so it also comes with a solar panel located at the top to keep the NiMH batteries charged even if it only receives a few hours of sunlight.

If you are placing the unit in an area that does not receive at least two hours of sunlight, you can buy an optional solar panel that can be plugged to the power jack at the back.

The set includes:

  • The main Mistbox unit with the filter
  • The sprayer bars
  • Attachment hardware
  • The AC charging adapter
  • User manual

Setting up your Mistbox

Installing your Mistbox is very easy as the set comes with everything you need to install the Mistbox unit, except for the host that connects it to your water line.

First, choose the best location for your Mistbox, which means picking a corner that is closest to your water supply and that receives a lot of sunlight to keep the unit powered.

You simply attach the Mistbox to a corner of your air conditioner using zip ties or screws, and then attach the sprayer bar to the filter that is attached to the main unit.  You then attach the sprayer arms with the nozzles pointing away from your air conditioner.

Lastly, connect the water hose to the water intake connector and your faucet.  Check the owner’s manual for more details on how to properly install your Mistbox.

After that, you could now install the Mistbox app on your smartphone and it will take you through the steps to connect to your Wi-Fi network.  You’re all set to go!


LCD Display22mm x 70mm gray segment display
Display typeIcon based
SensorsFive (Temperature, Sound, Electro-Magnetic Field, Vibration, and Ambient Light)
Wireless802.11 b/g/n @ 2.4GHz
Bandwidth requiredLess than 50MB/month upload, 5MB/month download
Battery7.2V NiMh rechargeable long life battery
Solar Panel96mm x 54mm High efficiency crystal metal matrix photovoltaic
Power Consumption0, solar powered.

Getting to know the interface

The Mistbox unit has three soft touch buttons:  1) the yellow ‘Wake’ button, 2) the green ‘Filter’ button, and 3) the blue ‘Water’ button.

If you want to test your setup, press and hold the Wake button to start a 30-second test.  This is also what you press to turn on the display.

Meanwhile, the Filter button allows you to reset the filter life when you replace the filter, and if you press and hold the Water button for five seconds, you will enter the Wi-Fi provisioning mode.

Activating the water saver mode is as simple as simultaneously pressing and holding the Wake and Water button until you hear an audible beep and see the “water saver mode” icon light up on the display.

How does the Mistbox work?

Mistbox saves you money by cooling the air surrounding your air conditioner’s condenser unit.  It infuses small water droplets to help the condenser cool the refrigerant that in turn cools the air inside your home.  By doing this, the Mistbox will reduce your air conditioning unit’s workload, therefore also reducing the power it consumes, while also making the AC unit itself more durable.

The Mistbox uses evaporative cooling, which lowers the temperature when evaporation takes place.  Evaporative cooling has been widely used in industrial cooling systems for a long time now and Mistbox is simply taking the technology to your home.

Not only does the Mistbox cool the condenser and help it work less hard, but your air conditioner will also have cooler air coming out of it.

Mistbox makes use of integrated sound, magnetic field and temperature sensors to help it know when to mist.  The magnetic field sensors help the Mistbox know when your air conditioning is turned off so even if it is hot outside, it will not start misting.

The temperature sensor helps it know that the room is very hot and that it should get to work.  You can also set a trigger temperature that tells it to start misting when it gets to 80 degrees Fahrenheit out.  All of these help ensure that you do not waste water misting when it is not needed, like when the air conditioning is off or when it is raining out.

It is that simple.  However, the Mistbox also learns from its environment, taking into consideration your air conditioning system and your climate.  It takes all these data to work more efficiently for more power savings while also using less water than is necessary.

Most of the other functions are related to the Mistbox app.

The Mistbox App

The mobile app that comes with the Mistbox allows you to have a wealth of information readily available.

Current Data: For one, the home screen shows the current weather conditions and the amount of savings you have made over the course of your use of the Mistbox.

Status Checking: The Status menu shows you just how your Mistbox is currently operating: whether it is currently misting or not, what mode it is in, the battery charge level, and the condition of your filter.  It will let you know if there are problems that you need to attend to.

Savings Data (Over Time): Then you have the Savings screen that gives you all the details on just how much you have saved while using the Mistbox, broken down by month.  It details the average high temperatures for a particular month, the average daily usage of your air conditioning and the amount of AC time saved, as well as an estimate of the total amount saved for that month.

Support Information: Then you have the Support tab that allows you to view FAQs, videos, the manual, and installation guide and to visit the store for replacement filters and other things that you might need.

Settings Information: Then lastly, you have the Settings tab that allows you to customize the features of the Mistbox and its app, including the temperature trigger, the run time factor, whether to turn on the water saver mode, how often you would like to update the Savings Reports and whether you would like these reports to be e-mailed to you.

mistbox-appImage collated from different images from


On top of the expensive price tag, there are some things that you should consider before deciding on the Mistbox.

  1. Water Usage: For one, Mistbox uses lots of water.  Mistbox support confirms that it uses more than seven gallons of water in an hour.  Even in water saver mode, it can easily consume five gallons of water per hour of operation.  Now that may not cost much, adding only pennies to your water bill, but all that water gets wasted and ends up on the ground.  It’s good if you have a garden near your air conditioning unit, so you can channel all that water and keep your lawn green.  But for the most part, you’re left with puddles and mud.  It would have been great if Mistbox found a way to collect all that water conveniently so that you could reuse it to water your lawn, flush toilets, and other stuff.
  2. Limited Flexibility: The Mistbox also offers limited flexibility.  It has to be installed near your air conditioner.  While putting the solar panels on the control unit itself makes it look more solid and compact, the limited placement flexibility means that you would need to shell out an additional $60 for the auxiliary solar panel if your air conditioning unit does not receive any direct sunlight.
  3. Savings Vary by Location: Additionally, the savings you get from the Mistbox would vary differently, depending on where you live.  It would be best for places that experience low humidity.  For instance, a family living in Las Vegas spending $300 per month on their monthly electric bill would save as much as $73.50 a month, while a similar family living in New Orleans would have $20 less savings per month at only $52.50.
  4. Hard Water Limited: Speaking of local conditions, you might also want to check if you have hard water.  The Mistbox comes with a high quality filter that would keep your air conditioner safe from rust or mineral build up.  However, this filter must be replaced every year and is rated for a maximum hardness of 500 parts per million.  If you are using well water or hard water above 500 PPM, you might have issues with rust or calcium deposits and that means you might need to buy a separate filtration system.
  5. Cold Weather Advisory: Lastly, you might need to uninstall the Mistbox during the winter months.  The company says that the Mistbox should not have problems with mild freezing conditions, but advises that you uninstall the box and store it in the event of extended heavy freeze days.

Alternatives to the Mistbox

The Mistbox is in a league of its own.  A somewhat comparable product, the Cool Energy AC Mister, is cheaper at $249.99 and offers the same features as the Mistbox but it does not have Wi-Fi connectivity and has no mobile app available. UPDATE: It’s also recently been discontinued from most marketplaces.

The final verdict

The Mistbox is a great gadget to have if you want to save on your cooling costs.  It makes use of a mature technology that has been used for industrial air conditioners and has been successfully scaled down for home use.

It is very easy to set up and everything you need to install it comes in the box, and you can immediately forget about it except for remembering to change the filter every year and that takes only five minutes.

The savings are substantial as well.  The company claims that you could get the money you paid for the Mistbox back in just one season, but that is quite misleading.  You have to factor in the cost of all that water used for misting, as well as the yearly filter change.

Depending on where you live, the savings can vary widely, as well.  While it may take you longer than a season to recoup your investment, the fact remains that you do save with the Mistbox.

The addition of the mobile app is invaluable here.  You get a concrete proof of all the savings you get, along with statistics on how much less you have your air conditioning on and how long the Mistbox is operating.  That helps you appreciate just how much money you are saving, helping justify the quite steep price tag (check here for latest).

About the author

Patrick Sinclair

Patrick Sinclair is a geek; make no mistake about that. He runs All Home Robotics in his spare time so he doesn't have to think about his depressing cubicle and it gives him an excuse to buy expensive gadgets to review!


  • I thought about something like this many years ago but where I live, there is hard water, really hard. So my concern was buildup or scaling on the system which would then drop the efficiency of the system. My previous home was new and a year ago I moved into an also new home. At the previous house, the high pressure HVAC line was very hot while running. At the new house, it is cool to the tough and in fact when touching it is feels like body temp. So at the new house I don’t think this system would add much. The new house is larger but yet my cooling bills are less which is likely due to the high pressure line running cooler which would then mean during expansion, the cooling effect has a greater impact which then provides cooler air.

    IMO, a better solution to removing the heat still involves water but not with using a mist. If someone has an electric water heater this would offer them huge savings. More recently a heat pump water heaters have been made available. A heat pump is much like an AC system, so why not tap into the heat being produced by an AC system. Before letting the heat off into the air, it can be reclaimed with products like the Aquefier. After it takes the heat it needs to heat water, the remaining will then be let off into the air.

    I’m not saying that the Mistbox is a bad idea, I just think there are better ways to remove the heat being generated. Both the Mistbox and the Aquifer are trying to remove the heat generated, the main difference is one is reclaiming what is normally wasted.

    There are drawbacks to both systems. I think the biggest disadvantage of the Aquefier is that if you use hot water when the AC is not running, then your water heater will need to work. If your hot water heater is already full of hot water, then the Aquifer will not provide any benefits at that time. There are ways around this but it would add extra expense to the installation, a longer BOM and more space required.

    • Lance, thanks for the comment.

      I definitely agree that it is very much system/house dependent. I really like the alternative you suggest, however I’d be curious about the ease of implementation. The Mistbox (as of now) might be a better out of the box solution.

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