Vocab-lesson time! There’s not a huge amount of terminology used in conjunction with garage doors, but that which is used it rather important. So, break out the exercise books and learn the following well:
R-value: the amount of insulation offered by a garage door. An average door might require an R-value of around 4 or 5; in colder climates 6 or 7 is also appropriate. If you use your garage for work, a higher R-value is always preferable.
Headroom: the space between the top of the door and the ceiling, necessary to stop it hitting the top.
Backroom: the interior length of the garage, which will impact the size of the garage door.
Sideroom: (no prizes by this point) the distance between the sides of the door and the walls of the garage, necessary to stop it scraping.
Wind Resistance: the wind speeds a garage door can resist, before being torn off and tossed down the street. This is highly important because, not only is a tossed-door expensive to repair, it’s also highly dangerous for everybody outside! 100 miles per hour of wind resistance r is a good bet, though up to 170 miles per hour isn’t extravagant.
Balance: the door’s ability to be raised and lowered easily, but not too easily that it shoots up or crashes down. This is affected by the opening mechanism and torsion springs and, if unbalanced, a door should be altered by a trained professional. As a guide, you should be able to open and close the door easily with one hand.