I built 5 frame nucs and have 1.5 inch by 3/8" entrance on them. I also drilled a 2" round hole in the bottom and screened it with hardware cloth and over that regular screen to keep the ants out. Two days ago it was 100 degrees and the bees were on the entrance fanning and it was crowded. They were not all out bearding though. They are raising queens and my question is, can they keep brood cool enough and has anybody got there nucs so hot that brood has died?
I should mention also, that 2" hole is venting at the top because I have a deep upside down, top feeding sugar and a jar of water only since they might not have enough foragers.
I run black nuc's and have seen temps. in the high 90's and never had a problem.
I just shim up my tel.cover and that's it for a vent hole in the top.
(http://i952.photobucket.com/albums/ae9/GLOCK3/BEEKEEPING%202014/P6040005_zps6f62238c.jpg) (http://s952.photobucket.com/user/GLOCK3/media/BEEKEEPING%202014/P6040005_zps6f62238c.jpg.html)
Just saying.
They are very good at controlling the temp in the hive.
Most of my nucs have a one inch entrance. No other vents. Often their in full sun. Not uncommon for temps here to push or reach 100 deg.
I've never had a problem.
Bees can keep a full size hive cool with a 1" hole. They can't keep any hive cool if there is too much ventilation... Huber's research showed two holes did not ventilate as well as one...
Thanks for all the responses and Michael, that is interesting. I am thinking I was wrong though about what was happening. I will start a new post on it though because it is concerning.