What Air-Conditioner Do I Need For My Walk-In Cooler?

Over the years we've experimented with every type, brand and sized air conditioner we could get our hands on. Thanks to some of our customers for their part in the "lab" we have a lot of data to pull from to make the best air conditioner recommendation for your cooler.

NUMBER ONE PRIORITY Digital display: While there are different performance levels for the varying brands and models, the one constant is the air conditioner must have a digital display.


Type:

There are a few different types of air conditioners and we have found that certain ones work better than others. In order from best choice to, not such a good choice...

  • Window

    window unit

    Durable and efficient, the window unit is our preferred type of a/c. Whether it be installed in a walk-in cooler, truck, trailer or boat, the window unit has the best performance rate. Commonly available in the US, and best priced, these units will work even if your installing it in an 11 inch thick wall. Please see our list of brand recommendations[link to section on page] since certain brands work far better than others.

  • Mini-Split

    mini split

    These work so wonderfully with the CoolBot and are great options for folks who can't have a window unit. While they tend to be less accessible and more expensive in the US, many international customers find them to be more available. While they are more efficient than a window unit, the CoolBot systems use very little electricity anyway.

    So far the CoolBots have worked with every brand of Mini-split, including multiple off-brand Chinese units that no one has heard of. We had trouble with a Fedder's unit but only because the sensor is hidden and just 1 inch long (most have sensors 6-12 inches long). Ask the mini-split manufacturer what is the lowest OUTSIDE air temperature the unit will function in and compare that with your climate. Obviously even if the CoolBot works perfectly with your air conditioner, if it's a brand that stops working when outside temperatures fall below 40 and you live in Canada and need the cooler to be running over the winter, you will be unhappy! Brand recommendations below do NOT apply to Mini-Splits since so far every mini-split we've tried has worked.

  • Through Wall Unit

    thru wall unit

    Thru-the-wall units are twice the price and for some reason we seem to be having (slightly) more electrical problems with thru-the-wall units than we see with window units. Nothing serious or un-workable, but... unnecessary annoyances. If you have a thru-wall unit, don't hesitate to use it, though! We have 14,000+ units out there, I'm talking more about statistically higher problems, plenty of people are happily using thru-wall units with no problem.

  • Portable A/C

    portable a/c unit

    Any and all brands of "portable" A/C units - There are single and double hose models. Single hose models do not work AT ALL with the CoolBot. Double hose models work, but they are extremely inefficient and you won't be able to get the room very cold (only okay for 45F or above). People making cheese caves are the only people that seem happy enough with them, but even if you are doing a cheese cave, for efficiency sake we still don't love these!

  • RV Rooftop Units

    rv ac

    Only a couple companies make DIGITAL RV units. Dometic is one of those companies. They have a more and a less expensive line, and we think the LESS expensive line would work better because it's a bit more high profile, giving it more surface area for cold transfer.

    I've only had two people try them, and both wrote back positively, but one guy only needed to be at 45F and the other guy had SUCH a tiny space he was cooling that it wasn't much of a challenge to be in the thirties.

    We know window units work in mobile applications, from bouncing down the road on trucks and chugging along over seas in oyster boats. The surface area coils on a standard window AC unit is impossible to match with an RV unit. For more on mobile applications see our FAQ page.

    NC State has really detailed instructions on how to build a mobile cooler (the Pak N' Cool) with a CoolBot including mounting a window air conditioner in the side of a trailer... other people do this on vans and trucks as well (using window units). RV units are NOT as common. To learn more, see our page COOLER CONSTRUCTION

  • Dual Heating and Cooling Units

    We don't recommend the "heating and cooling" air conditioners because they are so much more expensive than normal air conditioners. ALSO (the ones I've seen so far) aren't even automatic!!! So you have to set it to cool mode or heat mode... which is bad if you live in a place that has cold NIGHTS and warmer DAYS. They do work with the CoolBot though, so if you have one you can use it.

  • Inverters

    Inverter units are great, and run fine with the CoolBot, but on all the modeling tests that we've done, they don't actually pay off. We just did a comparison for someone in Mexico with the help of a neat program made by University of California for measuring electricity use and I was so surprised to see that the actual dollars saved between the inverter and non-inverter model are so small that it doesn't pay for the extra expense of the inverter model for 15+ years.

    It's not that the inverter model isn't more efficient, it's that the cost of running the CoolBot and AC per month is already so low that what looks like a really significant PERCENTAGE is actually very small in dollars per month. Not only that, but the way we cycle things on and off while we do make use of the efficiencies of the inverter technology somewhat, it's not as awesome as it could be because of the nature of what we are trying to do in terms of temperature goals.


Brand

Now that we have the best type of a/c figured out, we will highlight the best brands.

Top Supported Brands

1000's of people use one of these brands. Buy one of these brands and we'll never have to talk to you!! Canadians -- see below

  • GE Brand:

    • Best brand since the 2013 redesign. They now restart automatically after a power failure and they work fine in the winter.
    • Be careful about buying pre-2010 used ones. They are very different.
    • A small fraction of 1% failure rate on compressors so far not including problems just out of the box (could have been dropped at Home Depot).
    • They are sold at Home Depot and WalMart.
    • Some models (we can't predict) have a 2nd "hidden" temperature sensor that makes installation take about 5 minutes longer (our instructions cover this).
    • We love this brand.
  • HAIER:

    • At WalMart, Costco, Sam's Club.
    • A bit cheaper than GE or LG.
    • There are not great reviews for these online at walmart.com, but we have direct experience with THOUSANDS of people using them with CoolBots for many years now (and we no relationship with HAIER or WalMart) and think they are GREAT
    • These have a slightly higher rate of problems "out of the box" but if they last for 1 week, they will last forever.
    • Starting in 2010 they added wording to their instruction saying they don't work if *outside* temperatures fall below 60F. But this isn't true, these are great through even Canadian winters and nothing changed in 2010, just the wording in their instructions.
    • We love HAIER units.
  • Danby:

    • Popular Canadian model.
    • Seems to be working fine, now since 2011.
    • We do NOT like pre-2011 Danbys, so don't buy used. The compressor was great but tons of electrical problems.
    • We have hundreds of people using these in Canada with under a 1% failure rate since 2011

Readily available to you locally you probably have LG (only in low-btu sizes -- and we don't like this brand anymore) or DANBY and then you have our most-favored HAIER units available as well through mail-order at airconditionercanada.com out of Quebec. They may be available mail order from other places, but airconditionercanada.com has specially ordered a bunch of larger 24,000 BTU HAIER units for CoolBot customers in the past. We are not affiliated with them and have never met them, but they seem nice on the phone, and that they bought in the inventory is pretty awesome for us! I know a lot of our customers buy from them and I have never heard a single complaint.

Click here for a complete list of supported air conditioners


Unsupported A/Cs:

These units have had so much failure rate that we do not offer tech support for them. Avoid these A/C's like the plague

  • Frigidaire:

    • VERY bad choice.
    • They don't work when it's cold OUTSIDE (like even in the 40's -- they shut the compressor down and won't restart it until you UNPLUG THEM. Wait for 30 seconds... and then replug them in).
    • They also don't work if your inner room gets below 38F even when it's hot outside!
    • Plus the electronics are WACKY.
    • We have more calls for people who use this brand than all other brands combined (because all the people with Frigidaires need to call us a couple times a year with some new weird problem).
    • A $4.00 repair on a GE, that requires just plugging something onto the board will cost you $120 on a Frigidaire and require a degree in electrical engineering
    • Even if you get it on a half-price sale it's NOT WORTH IT.
  • Maytag, Tappan, and Westinghouse

    • Are all the same as Frigidaire (made by Nordyne)
  • PerfectAire:

    • A horrible, horrible, choice.
    • If it works for a while, that's great, but there is no consistency

Click here for a complete list of unsupported air conditioners.


Size

Now that we have the right type and brand figured out, we will need to determine the best size for your space.

This is a chart showing the size air conditioning unit we recommend to cool a well-insulated room.

The "industry standard" insulation for a walk-in cooler is at least 4" of styrofoam in walls, ceiling and floor (minimum insulation value of R-24).

These figures are for a 38 F room, with 8' ceilings, opened no more than 4 times per hour.

Dimensions of the Walk-In Cooler Size of Air-Conditioner
6' x 8' 10,000 BTU
8' x 8' 12,000 BTU
8' x 10' 15,000 BTU
8' x 12' 18,000 BTU
10' x 14' 24,000 BTU
(Air conditioner vs. room size for CoolBot systems @ 38F)

Restaurants need to be below 40F to be food safe. Most set it on 38F to give themselves a buffer. If you'd prefer to be consistently at 36F, upsize at least one size. Upsize TWO sizes if cooler is opened once every 10 minutes.

Florists/convenience stores with display coolers (glass doors) need to upsize at least TWO sizes. Glass leaks a lot of cold. Florists should consider upsizing one level anyway to allow for a lower FAN speed. CoolBots are HIGHLY recommended by industry groups for Florists and flower growers. Less wind on the flowers, less drying, higher quality product in the end.

Wine coolers, cheese cave or cured meat folks that only need to be at 50+F can use smaller air conditioners. Email if we can answer any questions!

If you need help determining the best size a/c for your space, Click Here