The easiest & most reliable means of avoiding this is to set up automated greenhouse vent openers.
The last thing you would like to have happen is for your plants to perish because they literally were cooked.
The sun is a robust source of energy and a small greenhouse can reach blistering temperatures in just a few hours.
After all that is how they are designed. To capture solar energy.
greenhouses have light-weight roof vents and could require a stronger vent opener to keep them closed or prevent them being blown away – check before you buy.
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If you have a greenhouse, you understand how quickly it can heat through to a sunny day, even in winter.
You may make sure your greenhouse ventilation is constantly regulated Greenhouse Vent Fan during hot summer months, whether you’re at home or not, by installing an automated vent opener. It contains a wax that expands when heated, opening the vent. 
When the temperature falls, the wax contracts and the vent closes.