Is a °CoolBot Really as Efficient as a Conventional Compressor?
Yes! We have a ton of independent data to suggest that using a °CoolBot with a window air conditioner or a ductless mini-split air conditioner is more efficient than a conventional refrigerator compressor.
We’ve had hundreds of customers give us feedback about their lower electricity bills versus the conventional refrigerator compressor they used to have.
Additionally, NYSERDA, (the NY State Energy Research and Development Authority) contracted for an independent analysis to measure the efficiency of a °CoolBot-driven system versus a standard cooler.
This Report from NYSERDA (New York State Energy Research and Development Authority) study confirms that the °CoolBot works great and does not stress out the air conditioner or push it into unacceptable cycle times (which is another question that we get asked a lot). NYSERDA found that under certain parameters a °CoolBot-driven system can be up to 40% more efficient than a conventional refrigerator.
Although the °CoolBot-driven system is typically oversized versus a conventional cooler from a BTU perspective, it saves so much energy as an air conditioner typically uses only one 300 watt fan, while a conventional refrigerator compressor uses 3, 4 or 5 fans, depending on the size. One major benefit to a one-fan system is that certain flowers and crops (e.g. delicate flowers or baby lettuce) will stay fresher for longer due to the reduced air movement in the cooler. The trade-off is that our recovery times back to the desired temperature can be slower than a conventional compressor if the door is left open and the cool air is allowed to escape.
Is a °CoolBot just a Thermostat? Does the °CoolBot Include a Thermostat?
The °CoolBot is not just a thermostat! The °CoolBot is a device which uses multiple sensors and a programmed micro-controller, which when attached to a standard off-the-shelf air conditioner, functionally replicates a more expensive conventional walk-in cooling system.
The °CoolBot does include a digital thermostat so you can set it to run at whatever temperature you want (between 32°F – 65°F / 0°C – 18°C ). However the minimum recommended temperature is 34°F to avoid freezing up the A/C.
Does the °CoolBot run down to 32°F without freezing up?
°CoolBots can be set down to a target temperature of 32°F (0°C), however we recommend setting it no lower than 34°F (1.1°C) to prevent the A/C from freezing up. Most customers use their °CoolBots in the 38°F – 40°F (3.3°- 4.4°C) range, which is great for most veggies, meats, and prepared foods (most fridges are set at 38°F (3.3°C)
Can I mount the °CoolBot outside of the Cooler?
We designed the °CoolBot to work in a cool, dark and moist environment. Prolonged exposure to the sun can impair the °CoolBot’s buttons, and mounting the °CoolBot’s wires through the wall could damage them.
If you want to know the temperature of the cooler from the outside we strongly suggest either an indoor-outdoor thermometer or upgrading to the °CoolBot Pro to monitor and get notifications via the Wi-Fi module.
Can I use one °CoolBot for two A/Cs?
You do need a separate °CoolBot for each air conditioner, as each A/C they freeze up at different rates.
Can I extend my sensors?
Sure! There are a few options:
- Buy an extender from any electronics store; just be sure the plug fits exactly (2.5mm mono)
- You can splice in a little more “stranded wire” using very light gauge wire and wire nuts. 24 gauge wire is probably fine for just 3 feet, or you can use a heavier gauge wire for longer extensions.*
*It will void the warranty on the sensor cable that you cut, but we don’t void the warranty on the °CoolBot. If the splice doesn’t work, head to our Shop to purchase a new sensor.
Do you ship °CoolBots internationally?
Yes, we do ship °CoolBots internationally.
Can you connect me to someone using a °CoolBot in my area?
When we first started the Company in 2006, we were really active about connecting people. Since then, we have over 50,000 installations in every state, so there is a chance that someone near you is using a °CoolBot right now. Unfortunately, we don’t share customers’ names and businesses information anymore for privacy and management reasons. However, we do have a ton of customer testimonials and blogs sharing their stories.
You can see testimonials for your specific use case on the following pages:
We also have links to online and print articles about the °CoolBot on our Press page.
Finally, we’re actively recommended by multiple land grant colleges (such as UC Davis, Cornell Small Farms Program, and University of Vermont) and the USAID program in coolers large and small. In fact, quite a few universities as well as NASA’s SATOP program have contributed plans and support to °CoolBot, including some financial cost-share programs for small farmers who want to buy °CoolBots to save money. See our Research page for more information.
Is it possible to use a °CoolBot-driven system off-grid?
Yes! We have customers using solar power to run their systems. The systems can be expensive due to the inverters and batteries.
Another option is to use a back-up generator for situations where the grid is unreliable.
For folks who are using solar power, the keys to success are using a mini-split A/C (for energy efficiency) and keeping the cooler as small and well insulated as possible.
We’re happy to help with any specific information for any one who wants to do it.
Can I use an A/C with knobs? Does the A/C display have to be digital?
It would be great if the °CoolBot could work with analog, knob style A/C units, but unfortunately they don’t work. The °CoolBot heater can’t overcome the mass of the metal capillary tube sensors that are present in A/C’s with knobs. The digital ones use low mass thermistors which are easy for our heater to work with.
Can I use a portable air conditioner or a rooftop unit?
Portable air conditioners and rooftop (RV style) units do not have the cooling power needed to efficiently use the °CoolBot, we have had hundreds of customers unsuccessfully try using them. They usually have too much temperature fluctuation and/or can’t hold temperature.
What size air conditioner should I buy?
We have a sizing and brand recommendation chart available on our Air Conditioner Selection Guide, but to figure this out for sure, it depends on a lot of factors including cooler insulation, ambient temperatures, the ground temperature where you live, if you are storing anything which produces heat, and if the cooler is indoors or out in the sunshine.
Fill in our Cooler Construction Advice Form and we will get back to you with the best size for your cooler.
Will the °CoolBot reduce the lifespan of my A/C?
Surprisingly it will not!
A °CoolBot-driven A/C in a walk-in cooler will cycle less than it will in a residential setting.
In your tightly insulated walk-in cooler, the A/C compressor will cycle on far less than a residential setting. Most of our customers with well-insulated cold rooms report that the A/C compressor runs in average 15% – 35% of the time compared to 80% – 90% in a residential setting during hot summers.
Will the temperature display of the A/C still be operational or accurate when the °CoolBot is attached?
Some A/C’s display a set temperature, in most cases will be 60F, other A/C’s display the temperature that the A/C’s temperature sensor connected to the CoolBot’s heater is reading.
When the CoolBot heater is on, it is calling for the A/C compressor to come on; therefor the A/C may display a high temperature of 90°F+ (32.2°C+). This number will drop rapidly when the °CoolBot cycles off.
Regardless of what the A/C digital display says, the °CoolBot will display the actual room temperature. It has a very sensitive temperature sensor, and will changes quickly. If you need to see temperature from the outside of the cooler, a lot of customers like an indoor-outdoor thermometer or you can now monitor and get notifications with the new °CoolBot Pro and a Wi-Fi module.
Can I run the A/C in Energy Saver Mode?
We do not recommend using the Energy Saver mode. If you do, there are pros and cons to consider:
Pros of running Energy Saver Mode:
- Saves a little Electricity
- The fan turns off when the compressor turns off, but the fan will still periodically cycle on to circulate air in the room
Cons of running Energy Saver Mode:
- The room recovers from door openings more slowly
- If the fins freeze up, it is probably too warm outside to run in Energy Saver, so you would need to switch back to the Cool mode
- It cools down field-hot produce more slowly (especially for higher quantities of produce). if you load up a lot of produce, you should switch out of Energy Saver and reset your heater settings back to “d1”
If you do decide to run the AC in Energy Saver, you need to change the HEATER Delay setting up to “d3” from the default of “d1”.
To do that, do the following:
- Tap the RIGHT arrow to go into “heater” mode (the light under “heater” will be on, and “F” will be in the display if you are in the US, “C” if you are elsewhere)
- Tap the CHECK MARK button 3 times (or until you see “d1” blinking in the display)
- Tap the right arrow twice to change to “d3”
- Press the Check mark once to lock in the new setting. The display reverts back to normal in 20 seconds.
I saw that you recommended a 12K BTU A/C for an 8x8x8 room. Can I go up to a 15K, 18K or 24K BTU unit?
Yes! The temperature will drop down faster, recover from door openings quicker, and be able to get colder than 36F. Additionally, you may actually save money in the long run even though you spent more for a larger air conditioner up front.
For example, our recommendation for an 8x8x8 room is 12,000 BTU’s:
- If you bumped up one or two levels you’d be at 15,000 BTU’s or 18,000 BTU’s. In both cases, you get more surface area to transfer cold, so you can run in Energy Saver mode most of the time (it’s best to run in standard mode an hour before and after loading up and if it’s extremely hot outside). That could save you $15/month, which over a few years will have paid for the extra cost of the bigger air conditioner. A 15,000 BTU A/C is good, and a 18,000 BTU A/C is even better.
- If you wanted to go up three levels to 24,000 BTU’s, you wouldn’t save more money in electricity, but you could drop the temperature even faster and could go even colder. If you do want to upsize to 24,000 BTUs, be sure to fill out our Cooler Construction Advice Form and we can make sure you’re not oversizing the A/C unit.
Also, 18,000 BTU and 24,000 BTU air conditioners both run on 220 volts. That means you have less amps running on each leg of your power cord and your compressor will run more smoothly.
Can I use a Multi-Zone split A/C system?
Yes! We have customers successfully using multi-zone mini split systems with the °CoolBot.
You need to be sure the outdoor compressor is able to accommodate the BTU needs for all zones. For example, if your walk in cooler needed an 18,000 BTU unit, and there were 3 other units that handled 8,000 BTU each, then you would need an outdoor compressor that was able to handle 42,000 BTUs. Each zone operates independently from the others, so you can maintain different temperatures in each zone.
Should I get the highest SEER or EER? Inverter or Non-Inverter?
Don’t bother getting an A/C with the highest SEER or EER. Regarding mini splits, just get an A/C with 13 SEERS and you will be set.
Can I use the °CoolBot on a truck or in a trailer?
Yes! We have over 1,000 mobile applications running °CoolBots including trucks, vans, box trucks, slide-in units in the back of pick-up trucks, boats and trailers. We do not recommend using an RV roof mount A/C unit as they don’t work well with the °CoolBot. See our video and guide for building a Trailer Cooler for more info.
Will this work for cooling meat?
Yes! We have thousands of hunters and many small commercial meat processing facilities using °CoolBots to keep their meat cool.
For more information on coolers for hunters and meat processors, check out our page: Hunting & Meat.
Will this work to cool my flowers?
Yes! Thousands of florists use the °CoolBot to keep their flowers cool, and we’re recommended by the American Society of Cut Flower Growers. See our Floral page for more information and best practices!
Is °CoolBot NSF approved? Will this work in restaurant kitchens or commercial kitchens?
There aren’t any NSF certified air conditioners, so no restaurants with an air conditioner in their commercial kitchens have them NSF certified.
We are running in thousands of inspected commercial kitchens and inspected meat processing operations with no problem. Many people also build their own coolers and use FRP (fiberglass reinforced panels) on the inside. There are NSF certified walk-in cooler panels. You can check with your local department to find out if that’s necessary.
One inspector was concerned that the °CoolBot was not NSF certified. Our controller is legally classified as a thermostat, and there are no NSF certified thermostats. It is of course okay to have a thermostat in a kitchen (even smart programmable thermostats). One compromise could be to have a NSF certified thermometer to track the temperature.
The best thing to do is ask your local inspector ahead of time. We have 50,000+ units out there, thousands of which are in commercial kitchens. We would be happy to speak with a local inspector who is concerned or questioning the idea.
Will the °CoolBot keep my wine cellar cold?
Yes! The °CoolBot is a great option for people wanting to keep their wine cellar cool.
50°F – 60°F (10°-15.6°C) is no problem for the °CoolBot. With consistent temperature and humidity between about 50% – 80%, we can keep your wine in the perfect conditions.
See the Wine Cellar page for more information and best practices!
Where I live has very high humidity. Can I still use the °CoolBot?
Yes! The °CoolBot / Air Conditioner combination has no trouble running in high humidity conditions – inside or outside the cooler.
We have customers in the bayous of Louisiana, the jungles of South America, India, equatorial Africa and even down in Papua New Guinea, all running with no problem in near 100% humidity outside their coolers.
Does the Air Conditioner dry out the air? What will the humidity level inside the cooler be?
The humidity level with a °CoolBot and air conditioner usually ends up in the 80% – 90% range. If the cooler is empty or nearly empty, it will be slightly drier than if it is more full.
Even in a dry climate like Arizona, coolers usually end up in that 80% – 90% humidity level. Outside it might be 25% relative humidity, but when you open the door and that hot/dry air comes rushing into the room, it very quickly cools down to 50°F – 60°F (10°-15.6°C) degrees. Therefore, that exact same air that outside measured at a relative humidity of 25% will now measure at a relative humidity of 80% – 90% inside the cooler. Colder air can hold much less moisture, so the humidity levels go way up. Physics is great!
If you need more humidity, you’ll have to use a humidifier, and there is no conflict with running a humidifier and a °CoolBot. Simple and cheap vapor humidifiers can even come with humidistats to measure ambient humidity.
If you need lower humidity, you’ll have to use a dehumidifier – which means you’ll have to account for the extra heat that the dehumidifier puts out (which just means upsizing the air conditioner a little).
I need to keep a higher humidity than 90%. Can the °CoolBot work in these conditions?
Yes, it will definitely work with higher humidity.
Florists, flower growers,and cheese-makers who want higher humidity in their coolers seem especially happy with the °CoolBot. A °CoolBot-driven A/C moves much less air than a standard refrigerator compressor, and flowers dry out less and last longer. We have some additional humidity tips on our Dairy and Floral use-case pages as well.
You can also pick up a commercial humidifier to add to your cooler setup.
I am a vegetable and fruit farmer. Will the humidity conditions be okay for my produce?
Yes! The °CoolBot maintains the perfect relative humidity for vegetables and fruits. There is a misconception that air conditioners constantly dry out the air, but most coolers reach a steady state humidity range of 80% – 90%.
If you want higher humidity levels, you can add a vapor humidifier with a humidistat into the cooler. It will not affect the function of the °CoolBot or air conditioner.
For food safety and to minimize disease pressure in your produce, we think it’s better to think about humidity control on a “micro-climate” level. We recommend that you use proper storage containers: for example, use mostly closed crates for things that need higher humidity (baby lettuce) and more open crates for things that need lower humidity. For berries, use clamshell boxes.
You don’t have to spend a lot of money to store your produce for the optimal humidity levels: On the Huguenot Street Farm, Ron and Kate mostly used open sided/open topped crates, but then used plastic to line crates or lay over the top of open topped crates, and that worked fine.
I am using the °CoolBot for seed storage. Will I be able to have the proper humidity levels?
Yes, but you might need extra dehumidification. The °CoolBot is used in many seed storage facilities all over the world, and they all want to keep the combined humidity and temperature in Fahrenheit under a total value of “100”.
To achieve this, there are a few options:
- Try different temperature settings: You may find that storing at 42°F (5.6°C) gives you a steady-state of 50% relative humidity, so that’s a total of “92”; but, if you drop the temperature down to 35°F (1.7°C), you end up with a relative humidity of 70% (putting you at “105”). Try different temperatures and see where you end up. Our experience has been the right number for most people who don’t want to use any external dehumidification controls is going to be somewhere between 40°F – 50°F (4.4°-10°C).
- Keep the room sealed tight: Make sure all gaps and cracks in the cooler are caulked or spray foamed to prevent warm air from entering the cooler. Make sure the gasket around the door keeps a tight seal, and replace the gasket if it is cracked. Warm air carries a lot of moisture that raises the humidity level in the room once it cools down, and even small cracks are constantly bringing in a flood of moisture.
- Minimize door openings: If you have a commercial seed storage facility with a lot of traffic, add PVC door flaps to reduce warm air entry.
- Use a mechanical dehumidifier: It needs to be one that says it works in basements. Be sure your air conditioner is large enough to compensate for extra heat produced by the motor in the dehumidifier.
- Use chemical desiccants:
- Calcium Chloride. This has been the solution for a few people in developing countries where electricity is unreliable. While the quantity of CaCl2 affects the amount of humidity that is removed, the CaCl2 is able to remove twice its weight in moisture and can bring rooms down to 30% relative humidity. We have also heard that it can be dried and re-used.
- We find that Sodium Chloride doesn’t work well. Its steady state keeps a relative humidity of 72% at best, so it’s not great for seed storage.
For whichever method you choose, be sure to leave space around the product for adequate air circulation!
What if I have a cooler with no outside walls? Can I have the A/C blow downwards mounted on the ceiling?
Unfortunately no, you can’t mount a window air conditioner in a sideways orientation on the ceiling.
The best setup for a cooler with no outside walls is a ductless mini-split air conditioner. The evaporator hangs on the wall in the cooler, the compressor sits on the ground outside, and the two are attached only by tubes and wires so you only need to make about a 3″ hole in your cooler.
Venting the A/C into a non-climate controlled interior space such as a storage room or garage is fine. Venting the A/C into an air conditioned space is an option, but you will be paying for the additional electricity to cool the warm air blowing into the air conditioned space.
Portable air conditioners are not a good option since they are unlikely to get your cooler below 50°F (10°C) even in the best of circumstances.
Can I put a drain in my cooler?
Please avoid putting a drain in your cooler if you can. For hunters and meat processors who regularly hose down the inside of the cooler, you can install a drain, but be sure you have an air tight seal for it when you’re done using the hose.
A surprising amount of cold air will fly out of the drain hole; you can warm up the cooler by 5 degrees Fahrenheit with just a 3 square inch drain.
For most users, a mop and bucket is the best way to clean the floor.
Can I cool 2 rooms with 1 A/C by putting a partition in the middle and having one room be colder than the other?
Produce farmers often ask this question for vegetables that like to be very cold and some more delicate vegetables that will get damaged at very cold temperatures.
It is possible to use 1 °CoolBot and 1 A/C to have two different temperature zones in a cooler, but we don’t recommend the setup. The main issues are twofold:
- Temperatures want to equalize so you won’t have much of a temperature difference between the two sides over some time (e.g. overnight)
- It is difficult to get the partition set up correctly. Plastic cooler flaps are not very efficient, and you can only expect a few degrees of temperature differential. It’s better to build a wall with a door and work at adjusting a crack under the door by about 1/4″ at a time to try to get the temperature you want in both sides of the cooler
Given the issues discussed above, we recommend 2 separate air conditioners and 2 °CoolBots for this type of setup. That way there is no guess-work around the partition set up and you can adjust the temperatures in the two coolers as needed.
How important is it to have a floor in my cooler?
Cold air falls. By skipping the floor, you create an endlessly hungry “cold sink”. Concrete floors are a conductor (not an insulator) so no R value is gained there.
If you are pouring a concrete pad for your cooler, please use between R25 and R30 styrofoam underneath the concrete. You will have the benefit of the insulation and the easy maintenance of a concrete floor.
The only time you can skip a floor is if the ground temperature is less than 13°F warmer than the desired temperature in your cooler. (Do you live in Alaska? Are you only using the cooler for hunting when the ground temp is 53°F (11.7°C) or less? Do you only want the cooler to chill to 48°F (8.9°C)?) If you up size the air conditioner, you may be able to reach your desired temp, but it will cost you more in electricity and wear and tear on your air conditioner.
A truck or trailer will never cool properly without a well insulated floor. The cold air inside falls and heat from the road rises and warms the floor from the outside.
Can I build my cooler in my basement? Is it okay to vent into an interior room?
Yes! You can build a cooler and vent your air conditioner into a basement, storage room or lightly used space. You would not want it to blow into an area where there are customers.
A few tips:
- Proper set backs are vital for the functionality of the air conditioner, at least 2 feet on each side, top and back of the A/C (check owners manual for exact set back requirements for your model!).
- Warm air will be vented into your basement from the back of the A/C unit. It’s just warm air, and it’s not harmful. If you have windows, you will want to open them a little, or install a vent or an exhaust fan to keep the space comfortable and the back of the A/C ventilated. If you live in a cold climate, this extra heat may be welcome in the wintertime.
- Water will drip from the back of the air conditioner, and normally you can catch it in a bucket, It’s usually just a small amount of water unless you live in a very humid climate or are opening the cooler door a lot, which will increase the amount of condensate.
My wall is super thick. Can I still use a window unit?
Yes! You can use most window air conditioners through a wall that is up to 11″ thick. If your wall is thicker than 11″, consider these options:
- Ductless mini split air conditioner: The evaporator hangs on the wall in the cooler, the compressor goes on a concrete pad outside. They are connected by tubes and wires which run through a 3 inch hole.
- Through-the-wall air conditioner: Most manufacturers make a custom designed metal sleeve with all the necessary ventilation to use it in a thicker wall. Some are sold all in one piece, and some are an extra accessory for a standard window air conditioner. If you do decide to use a through-the-wall A/C, be sure to check out our Air Conditioner Sizing Guide to ensure the model will work with the °CoolBot.
My room is 20' x 20'. Can I still use a °CoolBot?
Yes! 20′ x 20′ installations are common for us and may require the purchase of two, three or four air conditioners (each with a °CoolBot). The number of and size of the A/Cs depends on cooler height, temperature goal, ambient temperature, and volume of product coming in the cooler.
We have done larger installations, up to 60′ x 40′. Please call or email us with the details of your cooler and conditions to help determine your cooling requirements.
How do I build my cooler into a preexisting room in my house?
The easiest way would be to leave the drywall in place and add rigid foam insulation on top. Use at least 2 layers of Styrofoam insulation, stagger the seams, and be sure to seal the corners tight. Sheet rock and Batt insulation will mold if condensation forms on either of them. Use caulk and spray foam on every gap, crack, or seam to prevent air from leaking through.
The R value of the existing insulation counts when you’re building a cooler in a corner of an already insulated room. Add enough insulation to equal R25.
Can I build a duct system for the heat exhaust? What about a duct system for the cold air?
We highly recommend against building any sort of duct work around the system.
The area behind and on the sides of the air conditioner where the heat is exhausted needs to be free and clear of interference. Obstructions will cause the compressor to overheat and shut off. Check your owners manual, but a medium sized air conditioner will need at least 2 feet of ventilation around the back.
Ducting the cold air causes the fins of the air conditioner to freeze up. The fins will also freeze up if cold air is blowing toward the A/C from a fan. The cold air needs to be able to flow into the room freely.
Avoid boxing the A/C system in on either side for the best results.
What do I do in the winter as my ambient temperature drops below freezing? Should I get an air conditioner that both heats and cools?
The air conditioners that have both heat and cool modes only heat at 60°F and above. They do not switch from cooling to heating automatically.
One solution that we’ve found is to buy a little heater (buy the blower type, not radiant type) like the Lasko Ceramic Heater or the Pelonis ceramic heater. Plug it into a pass-through thermostat like the Inkbird ITC-308 Plug and Play Temperature Controller, which is digital. The Inkbird is easy to use and to adjust. For instructions on how to set the Inkbird with the °CoolBot, check out our blog post “How to set up your cooler for the winter season.” A second option is the DuroStat Portable Waterproof Prewired Thermostat from FarmTek.com (Item #CR2045). This one is not digital like the Inkbird. Some of our customers (particularly for micro-brewing) have used the AGPtek STC-1000, but this is not a plug and play like the other ones. Make sure you choose a thermostat that can be set below 40°F!
Whichever thermostat you choose, we recommend setting the °CoolBot at least 4°F warmer than the heater so they don’t overlap and fight with each other.