IMHO, there are two advantages of having a greenhouse over growing in your home, humidity and convenience.
With my room humidifier, I keep my orchid room in the 50's. I suspect my plants would prefer humidity in the 60's or 70's, but it isn't practical for me; I don't want mold growing on my walls, etc. Of course, those LUCKY people with basements and converted attics can keep humidity much higher than me. That said, my plants seem to grow and bloom well under my conditions.
I have wood floors, and my plant stands are on carpets that have a plastic liner underneath. I have to be careful when I water. If I had a greenhouse, I'd have automatic watering, or at least I could water copiously and sloppily.
But I do love the control and security that indoor growing affords. I know exactly how much light my plants get, no cloudy days or guessing when to put up or take down the shade cloth. And I go to bed with a smile on my face. Even if the power fails, my orchids won't freeze (this might not be true for folks in more northern climes).
Orchids can prosper in a wide variety of situations. You take what you've got and do the best you can with it, and you can have success.