Temperature

[Jakob]

Hello!
I'm only just seriously starting with orchids. I have grown a Phalaenopsis or two before, but now i wish to begin with something more interesting.
Since temerature seems to be quite important to growing orchids i have three questions:

A: Tempearture groups:
I tried to understand that trough readig about it, but i would rather see someone checks my coclusions
So there are three (very generally speaking) groups: cool, intermediate and warm.
Cool growing should generally have quite cool nights, around 7-13°C, but can be warmer during the day Around 18 - 25 °C. Intermediate have also cool nights 13 - 17°C, but warm days up to 30°C. Warm groing orchids should always be grown above 18°C.
I understand there is some laxiness around these "rules" depending on the species and level of moisture in the air.
But, it does seem to be quite important to get the daily temperature difference, with cool needing the biggest.
Are this general guidelines correct? How importat is the temperature really? Very? Only for some? I read its possible to grow cold growing orchids outside during the summer?

B: sice i guess most of the world is too warm for cool growing orchids at least part of the year, how are they kept cold? (are elaborate (and probably expensive) cooling systems the only answer?) (heating is no problem but cooling seems more difficult) If the warm period is short enough, do they endure this discomfort or do they just die?

C: Living quarters in the houses are generally fit for warm growing orchids (i understand humidity may be a problem but i have two fishtanks in the room humidity levels are never below 60%, usually 80%, temp. around 20-26 °C ). Correct? And a bright hall thats 10-14° i winter and 16 - 20° in summer should be ok for cool growers?

Thanks for the answers! I really did try to find them online, but the iformation was sometimes contradictory and confusing. i'm really just begining with growing orchids seriously and anyway, i would like to see my conclusions either corrected or confirmed by someone experienced . I have 10 years of experience in aquarium fish, but so to speak I am like a fish out of the water when it comes to the orchids
Regards,
Aljaž