Heat produced by the video cards is pure ..... You don't have to live in Norway to get one of these cards.
First of all, all your overclocked Core i7 are outputting a lot more heat. Maybe you think it ain't so looking at the low temperatures you reached with the new, shiny aftermarket cooler. But thermodynamics isn't magic, and you can't make heat disappear. You can just move it somewhere else. And if you are cooling your whole PC on air, by your reasoning, you might be already ..... even with the coolest video card on the market. Oh, by the way, your fridge and your microwaves produce a lot more heat than your entire PC, so keep an eye on them!
Additionally, your PSU can produce a lot more heat than all the other components alone. This is true especially if you were cheap and bought a low-efficency PSU that wastes too much power as heat.
As for ambient temperature: 20°C is very low, usually only during Winter you get that low. Your PC will love that temp, regardless of what's inside it. 30°C is very high instead, and you will not tolerate that temperature very much. You can live with it, but you'll be better off cooling yourself first. If your ambient temperature is above 26°C you will need additional cooling for your room, or better cooling for your PC, regardless of what you are using.