Line art of a window showing the meaning of plumb and level.

If you like to watch home renovation videos, you’re probably familiar with a fair amount of contractor terminology. Sometimes when the window and door words start flying around it can get a little confusing. Plumb and level are two important terms for anyone doing window installation.

When putting in new windows, it is important to ensure they are weather tight. You achieve this by obtaining correct measurements. When measuring a window, plumb refers to the vertical planes, and level refers to the horizontal planes. See the illustration below for clarification: Remember, JELD-WEN always recommends hiring a professional for window maintenance or installation.

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