Is it okay to leave my freezer in the garage year round?

I keep my freezer in garage year round. Is this good for it? I was told it helps keep electricity bills down in the winter. My dad has a freezer in his garage too, but I think we should both bring them in in so my mom doesn’t have to go out in the cold to get something from the freezer. Please let me know if it’s not a good idea and what are the pros and cons of it.

Answer from Green Energy Efficient Homes

Up to a point (or rather, down to a point), a freezer will run more efficiently in a cooler area, because there is less ambient heat to transfer into the freezer interior, and so less work for the compressor to do to remove that heat.

However, freezers are designed and built within certain temperature tolerances, and the refrigerant used in any given freezer has a specific optimum temperature range. Any temperature below the proper range increases the risk of damage to the compressor, particularly if you get ice build-up on the compressor. The compressor may also become sluggish as the oils used to lubricate moving parts may thicken and slow it down, which will reduce efficiency. The damage may not show up right away as a failure, and could instead lead to less efficient operation – worn out moving parts leading to increased friction, which means more work for the compressor to achieve the same amount of cooling.

The refrigerant used in most recent freezers is a new ozone-friendly refrigerant that has a higher boiling point. So in a very cold garage it may not get warm enough to evaporate, which is the cooling part of the cycle, and as a result may not keep your food cold enough. One problem with keeping your freezer in garage is that as long as the temperature stays below freezing outside, you may think your food is being kept safely cold, but if the freezer isn’t operating properly it might just keep the food a degree or two below freezing, which is not cold enough. Foods kept at -1C or 30F won’t last nearly as long as those kept at the proper temperature of -17C or 2F.

Some older (and especially some very old) freezers seem to work well in cold ambient temperatures, at least in terms of continuing to operate for years. Apparently putting a newer freezer in garage is much less likely to provide ongoing trouble-free operation because of the way newer freezers are built. And because newer freezers are far more efficient than those built 10+ years ago, you will almost certainly use less energy with a new freezer indoors than with an old freezer in garage.

Another downside to keeping a freezer in garage through the winter is that cold air outside the freezer can cause frost build-up on the outside of the insulation layer within the freezer case, which will reduce the insulation value. So while you may save electricity initially by having less work for the freezer to do in the lower ambient temperature, over time you’ll reduce the freezer’s ability to keep that heat out. Come summer you’ll find the freezer uses more energy than before, because the insulation is shot.

Since almost no one measures how much electricity their freezer uses, and since people have (in some cases) been running a freezer in their garage for years without incident, there is a conventional wisdom that keeping a freezer in garage makes sense. But unless you have measured your freezer’s energy usage both indoors and out using a device like the Kill A Watt meter, and determined that operating it in the colder temperature is more, and not less efficient, you have no guarantee of energy savings, and you may also damage the freezer in the process.

A freezer that is disconnected and left in a garage over the winter should weather the cold much better – as long as you let it come up to ambient temperature for at least 12 hours before turning it on. But you can’t use an unplugged freezer to keep food reliably frozen!

If you can determine the minimum ambient temperature for the freezer, you can keep a freezer in garage by enclosing it in a smaller space within the garage and heating that space. Sometimes a heat source as small as a lightbulb will do the trick. Remember that the freezer itself is expelling heat to keep the contents cool; trapping that heat inside the small space (say, a plywood box) will keep the ambient temperature warm enough to let the freezer operate at a safe temperature. You could also use a Thermo Cube (as described in my Home energy saving devices page), which is like a thermostat that plugs into a wall outlet, and that you can then plug an appliance into. You would get the Thermo Cube TC-3, and plug a small lamp with a 100 watt incandescent light bulb into it, and enclose the light and the freezer in a small space. The Thermo Cube should turn on any time the temperature drops below 2C, and then will stay on until the temperature climbs to 7C, which means it will keep the compartment warm enough that you can keep the freezer in your garage while minimizing the risk of damage.

Of course, enclosing the freezer in a separate compartment makes it even less convenient than keeping the freezer in the house, so unless you are willing to (A) measure the freezer electricity usage both indoors and out, (B) go to the trouble of building a separate enclosure, and (C) deal with the several extra steps required each time you want to add food to the freezer or take it out, I’d say, time to move the freezer inside!

12 replies
  1. ted
    ted says:

    I am looking for a 120 volt thermostat that will turn on only when it reaches minus 5 and of course turns off below minus 5. I want to plug a freezer that is kept in an unheated cabin. We go every few weeks, but it seems senseless to have it running when the temperature is below the operating temperature of the freezer. Cant seem to find anything that works the opposite of a plug in thermostat.

    • Robin
      Robin says:

      The operating temperature of most freezers (ie the internal temperature) should be around -18C or 0F. I don’t think you’d want it to shut off at -5C – the food in your freezer would not last nearly as long if kept frozen at that higher temperature.

      In any case, you could use a thermostat like the Inkbird Digital Temperature Controller to do this – it supports both heating and cooling equipment, and a very wide range of temperatures. The above link is for the US; here’s the Amazon Canada link.

      In theory you’re not supposed to keep a freezer outside in cold weather, but as far as I can tell from some cursory research, the main concern is that, if the unit is left off (or shuts off because temperatures drop below the temperature it normally turns on), there is a risk that the lubricants get viscous to the point where, when the compressor later turns on, the compressor could stall on startup, or short out. But there seem to be many more cases of people getting by with a freezer in a garage or outside in cold weather, than of people reporting problems. So be forewarned of the risk, but you may well decide it’s a risk worth taking!

    • George
      George says:

      Small room heaters will turn and off when equiped with thermostat. Not sure of temp range and 120 volt cost something to operate.

  2. Ted Dakin
    Ted Dakin says:

    That is exactly what I have been looking for. Thank you very much. yes i think I will have it shut off when it reaches -18. That isn’t very often, but here it could get far below that for an extended period of time.


    • Robin
      Robin says:

      Freezers work by extracting heat from the freezer compartment into the space the freezer is located in.
      If the insulation around a freezer were 100% perfect, the freezer would just exhaust the heat after you closed the lid, and there would be no need to run the compressor again until someone opened the freezer door and let some of the heat back in.
      However, freezers don’t have 100% perfect insulation. Heat is seeping in all the time through the bottom, sides and top. That’s why freezer compressors run periodically to extract the newly introduced heat.
      Obviously, the hotter the room is in which the freezer is located, the more heat will seep into the freezer, and the more the freezer will run. So keeping your freezer in a cool place makes sense.

      • Patrik
        Patrik says:

        Robin, this sounds like good reasoning but unfortunately the physics work the opposite way, in that it becomes less effective for a compressor to work in cooler temperatures:

        When I ran my Samsung American-style fridge in the garage (annexed to the house, no damp cars in there etc, lowest ambient temperature about 5C, and not over 25C in the summer) it used about 3.6kw/h per day, while in the house I now use only 1.9 kw/h per day – figure this !

        “How do I know?” – I hear you ask…. I put an electricity meter between the socket & the plug.

  3. David
    David says:

    How about using the freezer you already have right next to the refrigerator?
    If you shop and eat wisely, you don’t need an extra freezer in the garage.
    Americans waste more energy and food than any other county.
    Unplug your extra freezer and donate it. That will save you money and get you a tax credit.

    • tom riddle
      tom riddle says:

      Some people need that freezer space because they provide their own food from gardens and trees. We freeze cooked pumpkin for use with pies later. Freezer jam and other goods from our orchard. Meat from our turkeys chickens cows etc. Deer, Elk. Seriously one full beef takes two upright freezers. Why accuse someone of wasting food when a freezer exists for the opposite reason. To preserve food. We eat 2 beef in a year no waste. About 15 turkeys and 40 plus chickens. It is easier to kill clean wrap and freeze them all at once and clean everything once and store it in the freezer. Thsn to do one here and there as they get old and tough to chew and continue to eat and poop. Our food transportation cost is zero. Our freezers dont change the power bill by more than $15/ month for all of them. Some people realize that there isnt always food in the grocery store and they don’t have to go every two days burning gas to do it. because they have what they need at home.

      One trip to the grocery store in a month vs fifteen for people like you. Unless you never even cook your own food and just eat out. Not realizing restaurantd wast more food than homecooked. But seriously 1/3 gallon of gas to the store and back 15 times is 5 gallons for twelve months is 60 gallons @ $3/ gallon @ $180 per year just to the store for food vs $15 for us. That pays for plenty of freezer space. Open your mind. Your way isn’t the only way.

    • Nit
      Nit says:

      Interesting you say that because the first thing most Europeans do when they move to the US is buy large vehicles and homes, and take up the American lifestyle.


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