Garage door photo eye (safety sensor)

How does a garage door actually hold its own weight?

A garage door is not lifted by the opener — it is lifted by the spring, and the opener only guides it. A residential door weighs 85 to 400 pounds, and the counterbalance holds that weight so the motor only has to overcome friction. That is why springs and cables are professional work while sensors and remotes are not: one group holds the stored energy and the other does not.

Garage door safety covers the balance test and what an unbalanced door does to an opener.

How do I know whether a spring is what failed?

Look at the spring itself before anything else. A fractured torsion spring shows a visible gap of roughly one to two inches in the coil, and it is the single clearest diagnostic on the whole door. Extension springs run along the horizontal tracks on each side and show the same break.

The sound is the other tell. A spring failing releases its stored energy at once, and people consistently describe it as a bang loud enough to be mistaken for something falling over in the garage — often heard from inside the house.

Then test the weight, carefully, with the opener disconnected and the door already closed. A door with an intact counterbalance can be lifted by one person. A door with a broken spring feels like what it is: 85 to 400 pounds of dead weight. If it will not move easily, stop and leave it closed.

Do not use the opener to test this. With the spring gone the opener is lifting the entire door weight through a drive gear rated for a balanced load, which is how a spring bill becomes a spring and opener bill.

What does federal law actually require here?

Every residential opener manufactured since January 1, 1993 for US sale must meet 16 CFR 1211: a closing door must begin reversing within 2 seconds of hitting an obstruction, a second independent protection system must exist, and the manual release must be red. §1211.16(b) also fixes the exact words your manual carries — among them “Have a qualified service person make repairs to cables, spring assemblies and other hardware.” — which is why this page's verdict is not our opinion.

What UL 325 and 16 CFR 1211 require covers the full standard.

What is the one-minute test everyone should be doing?

The reversal test, monthly, with a 2x4 laid flat in the door's path: it must reverse on contact. If it does not, stop using the opener until it is adjusted, repaired or replaced. It matters because this system fails silently — a door whose reversal has stopped working looks and sounds exactly like one that still does. CPSC recommends inspecting the door and opener every 30 days.

Children, pets and the garage door covers why the standard exists.

How long does this actually last, and why is it measured in cycles?

Springs are rated in cycles, not years, and one cycle is one opening plus one closing. That is the difference between a specification and a rule of thumb, and it explains why two identical doors last different lengths of time.

A standard spring is typically rated at about 10,000 cycles. High-cycle springs, wound from thicker wire on a larger inside diameter, run 25,000 to 100,000.

Translate that to your own house. At 4 cycles a day — leaving for work, back at lunch, one errand — that is 1,460 cycles a year, so 10,000 cycles is a little under 6.8 years. A household with teenagers and two cars burns through them well before the "seven to ten years" figure that gets repeated everywhere.

The cycle rating is a manufacturer specification rather than a standard, so you have to ask for it. It is also the number that makes two quotes comparable: without it, a cheap spring and a good one look identical on paper.

At what point should I stop and call someone?

• The door is very heavy by hand with the opener disconnected. The counterbalance has failed.
• You can see a gap in the spring coil, or a cable that is frayed, slack, or off its drum.
• The door sits crooked, higher on one side, or has come off its track. It is still under full tension.
• The door does not reverse on the board test. The entrapment protection is not working.

None of those is calling too early, and the rule worth teaching at home comes from that same federal text: “NEVER GO UNDER A STOPPED PARTIALLY OPEN DOOR.”

Questions that come up next

Does a door that reverses mean something is broken?

No — the opposite. A door that stops and goes back up when it touches something is the entrapment protection doing exactly what 16 CFR 1211 requires. The fault worth investigating is a door that fails to reverse.

Can I disable the photo eyes to get the door closed?

No. That removes the external entrapment protection required since 1993, and it is the protection that exists because of the CPSC child fatality record. If a sensor is genuinely faulty, replace it — it is among the cheapest parts on the door.

Is it safe to use the emergency release with the door open?

The federally required manual text says to use it only when the door is closed wherever possible, because weak or broken springs may allow the door to fall rapidly. A great deal of DIY content advises the opposite.

Should I replace one spring or both?

If the door has two, quote both. The second is the same age and has taken the same number of cycles, so it is next. This is one of the few upsells in the trade that is genuinely honest.