How to Set Up Your Cooler for the Winter Season

As the warm months fade away and the cold season moves in, a lot of our users wonder how to manage the cold temperatures in their coolers. This guide will help you learn how to set up your walk in cooler for winter.
When temperatures outside fall below the freezing point, temperatures inside the cooler can drop low as well. If freezing temperatures inside the cooler are a concern for you, there is an economical solution you can implement. The idea is to maintain the temperatures inside the cooler above freezing but below the set-point of the CoolBot. We can do this by connecting any small space heater of the CONVECTION type (NOT A RADIANT ONE) to a thermostat controlled extension cord.
Let’s take a look at our recommended controllers and how to set up the system to solve the winter problem.
Recommended Pass-through Thermostats:

Examples of Heaters:

The following setup will keep your cooler above the freezing point during the colder months of the year, working between 32°F/0°C and your set temperature on the CoolBot. If you want to set up your cooler for different temperatures, please make sure that there is a difference of at least 4°F in between the set temperature of the INKBIRD and the set temperature of your CoolBot so they don’t overlap and work at the same time.

  • Leave your A/C and your CoolBot set up as normal and plugged in.
  • Plug in your INKBIRD Temperature controller.
  • Your INKBIRD will come in Celsius from the factory. Follow the instructions in the INKBIRD manual to change it to the Fahrenheit scale if needed.
  • Place the INKBIRD Temperature Sensor as close as you can to the CoolBot ROOM sensor. Give them a few minutes to adjust to the temperature.

  • If your INKBIRD Temperature display (the number at the top – labeled PV) is different from the one displaying on the CoolBot, adjust the Temperature Calibration (CA) of the INKBIRD sensor by following the instructions on the INKBIRD manual. The objective is to have both sensors reading almost the same temperature (within 1°F is ok).
  • Adjust the Setting Value (SV) temperature on your INKBIRD to 34°F/1.1°C following the instructions in the INKBIRD manual.

  • Adjust the Heating Differential HD value on the INKBIRD to 2°F/1°C following the instructions on the INKBIRD manual.

  • If all settings are correct you should be reading on your INKBIRD:
    1. PV: A value within approximately 1°F degree of the CoolBot display
    2. SV: 34°F (if set to display in Fahrenheit scale)
    3. 2°F (if set to display in Fahrenheit scale) when pressing the UP arrow (heating differential set value)

  • Plug your heater in the receptacle labeled HEATING on the INKBIRD plug in cord.

DO NOT plug your CoolBot or your A/C in the socket labeled COOLING of the INKBIRD. Leave that one empty!

  • Turn your heater ON and set the Heat level to Low.

NOTE: Heaters are very efficient. A small heater can handle large rooms. As a general rule, you need a heater that has (Area X 10) in watts power. For example, a 100 sq ft room would require a 1000W heater. If your heater is a 1200W or a 1500W, run your heater on Medium or Low (DO NOT RUN ON HIGH as the InkBird cord won’t be able to handle the load of the Heater). 
DONE! Check the system for operation to make sure it is performing as expected. Make the necessary adjustments if needed.

Comments 24

    1. Post

      Derek, you are absolutely right! Thanks for catching up on that. The rating of the InkBird is actually ~1200W@120V (~1000W@110V) hence the reason why we can run this 1500W Pelonis on the MEDIUM or LOW settings in a safe manner. It would not work for the HIGH setting as you correctly described. To correct the oversight, we have included a cautionary note regarding the heater settings. People who have 1000W heaters connected to the InkBird can run the heater on HIGH with no problems.

      1. The Inkbird ITC-308 you link to is rated for 1100W. The 306 models are rated for 1200W. It boggles my mind that someone would make a controller for an electric outlet and not be able to handle 15A (1800 Watts).

        1. Post

          The odd thing is that both the ITC-308 and the ITC-306 have the same 10 Amp relay inside, but for some random reason they advertise the 308 as a 1200W but not the other. However, it still brings us to the same question: How much more can it possibly cost to put a 15Amp relay inside? especially, considering that most space heaters nowadays are over 1000W! It boggles our mind too. The controller is well built and reliable, and considering the price and the functionality we still conssider it a good bang for the buck, people just need to be aware of the power output limitations to avoid issues.

  1. Hi love my coolbot. Commercial fisherman and hunter. I am one of your early customers. I had this problem years ago. I solved it simply by leaving the lights on in the cooler when drastically below freezing. 10 degrees and coolbot is right where I set it. 34-36. Simple and it works. Seeing I only use it when hanging deer in the winter I find it less expensive than heaters. Just sharing what works for me. Tom

    1. Hello Tom, great workaround and often our customers come up with the best builds and solutions. Thank you sincerely for sharing and Happy Holiday!
      John Bergher
      Vice President Sales & Marketing

    1. Thank you for the feedback Allen, glad it is working well for you.
      Happy Holidays,
      John Bergher
      Vice President Sales & Marketing

  2. I love my cool bot! I use it year round and had the same issue with keeping it from freezing in the winter. I use a heat lamp and it keeps it from freezing, but was looking for a heater because I don’t want the light to overripen apples or other fruit.

  3. I used the Inkbird with a heat lamp to keep above freezing in mine to keep a deer from freezing…. Had the Coolbot off too cold to even worry about it needing to run!

    1. Thank you Mark, we have a had a few clients send pictures this year on similar situations with the cold blast. Would enjoy hearing about your experience if you have time?
      John Bergher
      VP Sales & Marketing

  4. It would be really helfpul if you added a pdf or print button to your pages. I can’t carry my computer into the cooler while I am installing the Inkbird, and the Firefox print page option leaves a lot to be desired, lots of wasted space printing stuff from the page that you don’t need.

    1. Thank you Peter, great suggestion.
      Specific pages we can PDF for you and email directly or perhaps one of our customer engineers can jump on the phone with you during the InkBird set up? I will also reach out directly.
      Thank you Peter,
      John Bergher
      VP Sales & Marketing
      Store it Cold, LLC

  5. I’ve set the heater on low, does it matter what the other dial is on? I’m talking about the min/max control on the left of the heater when looking from the front.

    1. Post
  6. Great idea. I’m going to give it a try. It’s better than our previous method of just leaving the cooler door open a crack over nights in which the temperature drops below -15C.
    I have another concern with winterizing my Coolbot cooler. My A/C keeps freezing up. The bottom of the A/C collects moisture that turns into ice and eventuallly obstructs the fan. I’ve drilled a drainage hole in the bottom of the A/C and sandwiched a heat cord between the bottom of the A/C and a 2″ piece of styrofoam insulation. This works pretty well but it still freezes up from time to time. Any ideas?

    1. Post

      Hi Josh,
      Is your air conditioner on a good tilt so the condensation flows freely to the back of the AC? Could it be just too cold where you live? -15F is extreme, hopefully we won’t see that again for a while. That could have a lot to do with this problem as it sounds like you are compensating for this problem w heat tape, it’s possible that it is not enough to counteract -15F.
      You may want to plug that hole that you drilled in the AC. The AC wants some water all the way at the back which it recirculates with a slinger fan that keeps the compressor cooler and extends the life of the air conditioner.
      Best regards,

    1. Post

      Hi Travis,

      Thanks for reaching out!

      The short answer is: you could.

      However, this is not recommended because the Inkbird works in a very different way than the CoolBot does. First, the Inkbird cuts power to the A/C unit, equivalent to plugging and unplugging the A/C, and that is not good for the A/C. Second, you will not have a proper frost control like the CoolBot has (Fins sensor), drastically increasing your chances of icing up the A/C.

      If you have further questions our support team at will be happy to answer!


  7. Hi CoolBot team – we’re in northeast Pennsylvania and love our new CoolBot! We’re shutting down for the winter season and hope to get started again in March for incoming produce. What should we do to winterize if we won’t be using our cooler and don’t need a heater? Should we take the air conditioner out and store it? Simply unplug from electric and keep everything as is? As we enter the early spring, what should we do to get our CoolBot up and running again? Thanks for any advice!

    1. Hi Miranda,

      Thanks so much for taking the time to write, and happy to hear how well the CoolBot is working for your produce cooler!

      If your cooler is just going to be unused during the winter, there really isn’t much to do. It’s a good idea to clean the fins on the “cold side” of the A/C monthly, and the coils on the “hot side” yearly before you close up the cooler for the winter, that way it’s ready to go for next year.
      After that, you can leave it installed in the cooler and just add a protective cover for the outside of it to protect it from the harshest of elements and keep critters out. If you Google “window air conditioner cover” you will see examples of those to purchase, or you can DIY it. Unplug both the A/C and the CoolBot, to protect them from any power-spikes. Then, come spring, all you really need is to uncover the A/C, plug it and the CoolBot back in, check the A/C is still in cool mode, energy saver off, fan on high, and set to its lowest temperature, and you should be off to the races.

      Thanks again for including the CoolBot team in your project, and please feel free to reach out if you need anything else, we’re happy to help.


      Guth B
      Customer Service

  8. We have a reefer container with a mini-split to provide cooling and heating for bottle conditioning our beer. We want to change it into a cooler with a Coolbot. As it is outdoors and subject to New England winters, it will require some heating to keep it to 40 def F. If we set up a Coolbot, will the heating mode of the mini-split (Fujitsu) still be useable to keep it from freezing? If so, how would we set it up and switch between summer and winter modes?

    1. Window A/C s are typically OK being used with a CoolBot when temperatures fall below the freezing point.

      Here is a link to our Support Library the last link on there is a great article on how to set up your °CoolBot Cooler for the winter season.

      If you are planning to use a Mini Split A/C then you might want to consider a different alternative as those can only work on the COOL Mode when the temperature outside is above 15°F (for most brands of Mini Splits A/C).

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