In the United States, the Consumer Product Safety Improvement Act of 1990 required that automatic residential garage door operators manufactured on or after 1 January 1991 conform to the entrapment protection requirements of the 1988 version of ANSI/UL standard 325. A requirement for redundant entrapment-prevention devices was added in 1993; such a system can use an electric eye, a door edge sensor, or any other device that provides equivalent protection by reversing the travel of the closing door if an object is detected in its path. 
In the market for overhead garage doors? Browse our selection of Pella garage doors. You'll find many options for single garage doors, double garage doors, insulated garage doors and even roll up garage doors. Lowe’s also carries garage door screens—great for those who love to spend hours in the garage, but don’t want to deal with the bugs and pests that invite themselves in. We also carry garage door hardware, garage door springs, garage door decorative hardware and garage door sensors, and don’t forget to ask about our garage door installation and garage door opener installation. Once you've decided a garage door fits your home, you'll need to find the garage door opener that works best for you. At Lowe’s, we carry Genie garage door openers, Chamberlain garage door openers and SOMMER garage door openers that will work seamlessly with your garage doors. We now offer a garage door opener that's compatible with your Iris home automation system, too. Whether you prefer opening your garage with a garage door remote or garage door keypad, you'll find it at Lowe’s. Our selection of garage remotes includes everything from universal garage door remotes to specific brands like Chamberlain garage door opener remotes and Chamberlain garage door keypads. We also carry backup batteries, nylon garage door rollers, garage door parts, garage door opener parts and rail extensions to make sure your garage door is in good working order. Plus, we even offer garage door installations services, which include garage door spring repair and replacements, and garage door cable repair and replacements. We can also replace your garage door weather seal, also known as garage door threshold seals, and install a new garage door opener battery.
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.
This is the electric opener which operates this door. I'm picturing it here because you pull the rope to disconnect the trolley, run the trolley under power to the fully-open position, and then disconnect power before working on the door. Then you should lock the door down with either the security lock or with Vise-Grips or C-clamps. This avoids the door lifting when you don't expect it as you are applying spring adjustments. It you were to foolishly overwind the spring without the door locked down, you could possibly find the door trying to leap up to the raised position when you aren't prepared. That would likely knock your grip off the winding rods, with potentially disastrous results. I like to work under the safety principle that serious accidents should be physically possible only when you make two or more stupid mistakes at the same time.
The electric overhead garage door opener was invented by C.G. Johnson in 1926 in Hartford City, Indiana. Electric Garage Door openers did not become popular until Era Meter Company of Chicago offered one after World War II where the overhead garage door could be opened via a key pad located on a post at the end of the driveway or a switch inside the garage.
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).
Now 13 pounds of force must be respected when backed by many hundreds of foot-pounds of stored energy, waiting to be released. Holding this torque is equivalent to stalling a 3 horsepower DC motor. But holding and turning these handles does not require extraordinary human strength. Note that this maximum tangential force depends only on the weight of the door, and the radius of the drums, and is divided by the number of springs (some designs have only one longer spring, as mine did originally, instead of two shorter ones). Higher or lower lift distances imply more or less turns to wind the spring (and thus a different spring geometry), but not more force on each turn.
If return on investment is a priority and you don’t live in the West, your best strategy may be to buy a low- to moderately-priced door that significantly improves the look of your home. Consider adding an automatic garage door opener at the same time. The beauty of a new door and the convenience of an automatic opener are sure to be a winning combination.
Yet another professional wrote me to say that the red paint on certain components of these assemblies is an "industry standard" that signals, "Danger! Part under hazardous tension." Other items under tension like the bolts on the cable attachment plate on the door should therefore also be painted red. If so, then this is a new, ambiguous, unreliable, and little-publicized standard, because none of my old hardware shows it, red paint also means other things, and searching the Web does not readily turn up references to this practice.