heat is normal in a PC until after around 60 degrees centigrade., then it becomes dangerous to components. normal temperature range is 40s and 50s.
i can't really advise about watercooling, but i have seen systems rigged up that way, all of my PCs are on air-cooled. schemes. .. mostly watercooling is for users that tweak and boost the clock speed of their cpu.
there are a few temperature monitoring utilities available, the most common being speccy or hwmonitor. i use SIW, but it isn't available like it once was.
San Diego weather may not be a factor, unless you are taking your PC outside to use.
the affects of heat accumlation range from simple sluggsiness to component damage. if the cpu gets too hot, it will power down and then you will get that faithful BIOS message when you boot up again after that there was a thermal event. basically it is informing you that whatever is cooling your cpu isn't working.
ultimately, the OEM PCs such as HP have poor cooling schemes, air doesn't move very efficiently and there is a build-up of heat, sometimes to danger zone.
the reason being is the case, or as i like to put it, the enclosure., isn't bringing air in from the front, , the rear case fan is exhausting hot air, but there is a pressure difference that allows some of the heat to stay inside of the enclosure. that is why you see side panels with an array of holes, to offset that pressure difference. those same holes allow dust to enter, which over time can accumulate and hinder airflow. i use simple air filter material to cover those holes to block dust from ever getting inside. it isn't pretty, but it is very functional and effective.
there is market for custom enclosures, that have been designed to allow the airflow to be in harmony and keep heat from accumulating. i used a simple rosewill ranger mini-atx in one build a few years back, it wasn't very expensive and offered surprising functionality.
also, there are aftermarket hatsink/fan (HSF) configurations that the user can install to deliver improved cpu cooling. i like the Zalmans, but there are others that range in price and size.
Edited by synergy513, 17 May 2015 - 07:46 AM.