Right-hand versus left-hand winding: Springs are chiral, that is, wound or "laid" in either a left- or right-hand orientation. This is a critical property of their design and specification; you cannot substitute a left for a right or vice versa. If you were to grasp the spring in your hand, and if your right hand orients the tips of your fingers like the ends of the coiled wire when your thumb points "out" of the core of the spring, then you have a right-hand spring; likewise left (which end you grasp does not matter). (This also happens to match the "right hand rule" of magnetic polarity, if you happen to be knowledgeable in such esoteric subjects.) Another way to identify the winding is to examine the spring vertically in front of you; if the coils facing you rise going to the right, it is right-hand (thus you can remember, "rise to the right is right-hand"), and likewise left indicates left-hand. Another way is to view the coil axially; a right-hand spring winds in a clockwise direction as it recedes away, and a left-hand spring counter-clockwise. Yet another way, not so easy to remember, is to hold the spring vertically and compare the coil shape to the letter "Z" (indicates right-hand lay) or the letter "S" (indicates left-hand lay).
R-value describes the power of the insulation in your door. The higher the r-value, the stronger the insulation. Those doors will have better energy efficiency than doors that have a low r-value. Basic doors have an r-value of 0.0 with no insulation. The first step up gives you 1-3/8” insulation at a 6.5 rating. Next, a 1-3/8” thickness with Intellicore has a 12.9 r-value. The best option on the market is the 18.4 r-value, which has 2” Intellicore insulation.
Single panel doors are constructed from one monolithic panel. From the closed position a single panel door swings up and overhead with a hinge on each side (known as jamb type hardware) to the fully open position. A disadvantage of monolithic panel doors is that the swing up arc of the door occurs partially outside the garage. This means a vehicle must stop and park several feet in front of the door to avoid being hit by the garage door when it is opened.