Freezer in garage

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!