Greenhouses have to be designed to not merely capture solar energy but also adequately ventilate extra heat if temperature ranges get too hot.
You should always be 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 Greenhouse Auto Vent really well as they are located where hot air gathers naturally at the peak of the roof.
If vents in the roof are not possible, be sure to at least have a home window to two you can open.
Ideally you wish to have cross ventilation therefore two windows on two sides of the greenhouse work best.
However you should not leave the vents or windows open at nighttime as you’ll lose any heat gain and cool your greenhouse an excessive amount of.
Which means you close the vents or windows at night and what occurs the next morning: you forget! At this point your greenhouse overheats and if you’re unlucky, you lose some plants.
Or you forget to close the vents at 
nighttime and your plants suffer if the night is too cool.