(need answer fast)
If a laptop computer must be subjected to 30-degree Fahrenheit temperatures for about 3-4 hours, is it better for it to be turned on or off throughout the whole process? Seems that keeping it on would keep some internal heat going, and prevent condensation, but then maybe its active components wouldn’t like being cold either?
Also, since LCDs are liquid, do they freeze?
Also, this is for a laptop. Presumably desktop computers take cold differently? (only asking about a laptop)
There is a reason that computers has operational temperature range. This is obvious in hot climates as overheating can be problem.
On the other side cold temperatures are not directly harmful to computer. Condensation is. And it depends on many many different situations, it is easier for manufacturer to set some arbitrary low temperature operating rules.
If computer is off, then avoid drastically changing ambient temperature and do not turn it on until it’s temperature is roughly the same as environment. Otherwise LCD cracks and circuit fries might happen.
Temperatures around freezing point are ok if computer is always on and not moved around. Just do not breathe at it. 
Again, LCDs (you’ll notice ghosting first) and possibly batteries will first become bottleneck here. Also mechanical parts.
not at typical ambient temperatures. the LCDs we us in automotive have to be operational to -30C (-22F.) Now, while they’ll work, the response time slows way down and they’ll be sluggish and streaky until they get the chance to warm up.
It won’t condensate while in the freezing temps, it’ll condensate when you warm it back up. At least assuming you bringing back into house or some other place that doesn’t have oddly low humidity.
As long as you can prepare for it, I’d toss the laptop in a ziplock back, or at least a zippered laptop bag or backback or something at least somewhat moisture proof. Then when you get to your destination, leave it in there until it there for a few hours so the entire thing can come up to room temperature.
Sometimes in these cases, such as when I get electronics from Amazon and they’re sitting on the freezing cold for a few hours (plus how ever long they’ve been on a sub freezing truck), I’ll put the entire thing, box and all, near a heating duct to get it warming up.
At work I occasionally leave my laptop in the van outdoors at -20C for most of a day. I don’t do anything special, just use it. If it’s really cold, the battery doesn’t deliver much charge until it warms up, but other than that the only issue that ever comes up is condensation, and even that generally isn’t a big deal.
They can be if parts that contract and expand with temperature changes are bound to other parts that do not.
If that were really an issue, computers would be shipped in heated trucks. Since computers that are shipped in cold weather are not typically ruined by the experience, we can conclude that this is not an issue.
For any electronics, the storage temperature range is wider than the operating temperature range.
Turn off the laptop and put it in a bag (laptop case, backpack, whatever). After you bring it back indoors, leave it in the bag as long as possible, to minimize exposure to warm air until the laptop warms up.
OK thanks!
It could be an issue. We didn’t make laptops (not hardly) but we did have specs for transportation temperatures, knowing that our equipment might be shipped in quite cold environments. I assume PC makes have them too. I’m not sure Antarctica in the dead of winter would work, but any reasonable situation will be fine.
They’re shipped in relatively sturdy boxes, surrounded by styrofoam and airtight plastic bags. That all makes for pretty good insulation.
All the laptops I’ve ever bought have typically just had Styrofoam on two sides to keep it suspended in the box. Certainly nothing that would keep it insulated. Even if you totally surrounded it in styofoam, it’s only going to stay at room temperature for so long without it’s own heat source and I’d be surprised if that time was anything beyond a few hours when the temps get down below 30F. Certainly not the days or weeks between being stuffed in a shipping container and making it to an Amazon or Best Buy warehouse or the time it spends on a UPS truck or airplane.
Hopefully, minor condensation wouldn’t be an issue as the PCBs should be coated with conformal coating for this and other reasons. Power supply related items like switching power supplies, inductors, etc, if not properly coated might conduct and short.
If you have something like a Dell, you can look on the bottom panel and it’ll have a bunch of little symbols pertaining to certifications. Some of them are rated for humid and dusty environments and others aren’t. But, the widespread manufacturers like Dell, HP, Lenovo, have that. Mac’s may not, and that’s not that they are inferior, they just have a different target audience.
Most electronics are rated for storage down to -40 C (also -40 F). Check your manual if you want to be certain; it’ll tell you the ranges for operation and storage. But freezingish is going to be fine.
Would a cooling pad make a difference?
Thanks, but what if the computer was on in normal 70 F indoor temps, then taken outside (still turned on) through 40 F temps for, say, half an hour, then taken back indoors - all the while still on? Condensation time?
Hard to tell if it’s 30 F or -30 F they way you state it. If it’s 30 F I would hardly bat a eye over it, -30 F I would be careful in the warmup. Either way the plastic ziplock or other air tight container would be helpful.
Does it have a hard drive? If so, I believe most HDs for laptops use fluid dynamic bearings (FDBs). I know you’re not going down this low, but it’s probably worth mentioning that as the temperature gets below -10 °C, the fluid in the bearings thickens and the drive platter has a problem spinning at the appropriate speed. If the speed is low enough it can cause a boot failure.
That’s the whole problem. If it maintained it’s temperature, you’re fine. It wont’ condensate. But even if it’s on, it’s mostly going to fall asleep. The monitor will shut down, the memory is going to have very little activity, the hard drive will probably spin down etc. OTOH, if it’s just for a half hour, I’d say you’re too worried. Stick it in a back pack or padded carrying case and be done with it. When you get to your destination either leave it in there for a little while or put your hand on it. If it’s cold, let it warm up for a while, if not, you’re probably fine.
Yes, a ziplock bag would certainly be the best thing to do, but what you have to remember is that the laptop (or anything you don’t want to condensate) needs to remain in the airtight container until it’s warmed up, that’s the point. That way the moisture condenses on the outside of the bag instead of [the innards of] the device.
Keep in mind that probably half of middle and high school kids now have Chromebooks that they take home with them on a daily basis. Many of them being left in cars for the 10 minute ride home, a few hours to run errands or even overnight because the kid forgot it. It tends not to be a big deal and their not exactly the most robust devices.
Honestly, if it were me/mine, I’d just put it in something like a backpack or laptop bag and when it gets to it’s destination 3-4 hours later (as stated in the OP), I’d just leave it alone for a few hours. I’m sure it’ll be fine.
