Life support systems

[Laphtiya]

Not sure if I should be posting this here, but seeing as its an Add-on but not a specific one I figure general discussion should be a good place to start. I am looking for a fairly decent mod which will add life support systems to KSP. I've been searching here and the spaceport for about 2 hours now and I've found several examples but I am not entirely sure whats good/bad for best simulation. So I thought I would post here for some help/advice on good life support mods, my main cause for concern when reading up on these mods is that currently I have 7 Kermen living on a space station (Bill being one of them). I would hate for these guys to be found dead or actually having to rebuild the entire station because I have no systems in place.

Thanks in advance for any replies and sorry if I have posted this in the wrong section.