Greenhouses have to be designed to not merely capture solar energy but also adequately ventilate extra heat if temperatures get too hot.
You should always make sure you 
have sufficient vents in the roof of your greenhouse as heat rises and you want that heat to escape.
Greenhouse roof vents function really well as they are located where heat gathers naturally at the peak of the roof.
If vents in the roof are not possible, ensure that you at least have a home window to two you can open.
Ideally you wish to have cross ventilation so two Greenhouse Auto Vent windows upon two sides of the greenhouse work greatest.
However you shouldn’t leave the vents or windows open at nighttime as you’ll lose any kind of heat gain and cool your greenhouse an excessive amount of.
Which means you close the vents or windows at night and what happens the next morning: you forget! Right now your greenhouse overheats and if you’re unlucky, you lose some plants.
Or you forget to close the vents at nighttime and your vegetation suffer if the night time is too cool.