Expert: Daniel Humphrey - 4/1/2010

Question
Is there a standard for how big a window should be in any given room or wall size.  We are renovating an older home plus addng  a 20 x 20 extension.  All windows will be replaced and/or added.  What guidelines can you give me for how big a window should be/ could be in a 20ft wide x 9ft high wall.  It is oceanfront view.

Answer
Dear Fiona,

Window size is a matter of great debate between people designing homes. Except for a bedroom, which requires a window large enough to get out of (egress of 5.7 square feet), there is no rule of thumb on this.

http://www.bangormaine.gov/pdf/Egress%20Window%20Chart%20and%20Means%20of%20Esca...

Two main practical considerations for choosing window size are how much wall space you need in the room, and whether the windows will make it too hot in the summer sun or too cold in the winter. I've seen houses that are uncomfortable because of oversized windows.

I stay away from designing windows having panes larger than 5 feet by 5 feet, because the glass becomes too heavy to place safely without special equipment. Larger window units are best made up of several panes for that reason. If you are putting the window in yourself, ask about the weight of any window you order to make sure it is not heavier than two persons can easily and safely handle.

For looks, I like to keep the tops of windows above eye level and generally line up the tops of windows with the door height, or about 82 inches from the floor.  For safety and appearance on most applications, I keep the window sill height above 30" from the floor. Sills lower than this preclude placing furniture, like a couch, in front of the window.

My final word of advice is for you to select the very best views and make sure you see them from a good sitting place in the room. You don't need big windows for this, just good placement.

Good luck,

Daniel