Such systems tend to be build that handle any heat build-up be exhausted or radiated away. The makers knows it maybe a problem and thus allow for better static cooling. However, if the environment itself is a threat then consider a system where you can improve on cooling as the all-in-ones aren't that capable of a any cooling upgrades other than external. So, if you buy one, best to use it in A/C cooled room and/or where cooling is in a comfort zone for the PC. This is akk an opinion, as I see it.
I am considering buying the Gateway ZX 6810 all-in-one pc. Would someone be able to advise me if all-in-ones in general or this Gateway in particular be susceptible to overheating. I intend to use it in India, where outside temperatures can get pretty hot in summers (going upto 45 Celcius).
In other words, is over-heating a serious problem with all-in-ones?