How often should you replace a whole-house surge protector?
Updated July 2026
Replace a panel-mounted whole-house surge protector every 5–10 years, or immediately after one big lightning-scale event, whichever comes first. These Type 2 devices work by sacrificing themselves: the metal-oxide varistors inside absorb each surge and wear down a little every time, and a single close strike can spend a unit in one shot. Most have an indicator light that goes dark or turns red when the protection is used up, which is the unit telling you it is done. A spent one leaves HVAC control boards, appliances, and electronics naked to the next surge.
What changes the interval
| Your situation | Interval | Why |
|---|---|---|
| Panel-mounted Type 2 device | Every 5–10 years | The varistors degrade with every surge they absorb |
| After a nearby lightning strike | Check or replace | One big hit can spend the unit instantly |
| Indicator light went dark or red | Replace now | That is the device reporting its own end of life |
| High-lightning region (Gulf, Southeast) | Nearer 5 years | More surges mean faster wear |
| Utility with frequent surges or brownouts | Every 5–7 years | Repeated small hits add up |
| Point-of-use strip on electronics | Every 3–5 years | Layered protection, shorter service life |
The cost of skipping it
What skipping it costs: a spent surge protector fails silent, still bolted in place, protecting nothing. The next grid surge or switching transient then reaches whatever is plugged in: an HVAC or furnace control board is $400–800, a well-pump controller, a smart appliance, a TV, or a whole rack of electronics. The device itself is $100–300 plus $150–300 to install at the panel. Best practice is layered: a whole-house unit at the panel plus point-of-use strips on sensitive gear. Learn what a surge protector actually does before you shop.
How to do it (Electrician · $100–300 device + $150–300 install)
- Find the surge protector wired into or beside your main panel and check its status light.
- A green or lit indicator means it is protecting; dark or red means the varistors are spent, so replace it.
- Note the install date and plan a replacement at 5–10 years even if the light still glows.
- After any nearby lightning or a neighborhood surge, go check the indicator.
- Have a licensed electrician swap it: the unit ties to two breaker slots and the panel bus.
- Back it up with point-of-use strips on electronics for a layered defense.
Knowing the interval is the easy half. OnOtto reminds you at the right interval, and it won't let you snooze it into next year. Tasks persist until they're done, and completing whole-house surge replacements schedules the next one automatically.
Put this on autopilot, free for 30 daysFrequently asked questions
Does a whole-house surge protector replace my power strips?
No, they work as a team. The panel-mounted unit is the first line of defense: it clamps the big surges coming in from the grid or a lightning strike before they spread through the house. But it cannot stop the smaller surges generated inside your walls by motors and appliances cycling on and off. Point-of-use strips at the TV, computer, and other sensitive electronics catch those and clamp the residual energy the whole-house unit lets through. Layered protection covers both directions.
How do I know if mine is still working?
Look at the indicator light, that is exactly what it is for. A lit or green status means the protection is intact; a dark, red, or off light means the varistors have absorbed all they can and the unit is spent. Some models add an audible alarm. If yours has no indicator, or you cannot remember when it went in, treat anything past 5–10 years as suspect and plan a replacement. Unlike a breaker, a dead surge protector gives no other sign it stopped working.
What actually damages electronics if it is rarely lightning?
Most surge damage is not a dramatic strike at all. Far more common are switching transients: your AC compressor, well pump, or refrigerator kicking off sends a voltage spike back down the wiring, and the utility itself creates surges when it switches loads or a line fault clears. These are smaller than lightning but constant, and they nibble at electronics and control boards over years. That steady diet is what wears the varistors down, which is why the device needs replacing on a schedule, not just after storms.
Is it worth it in a region that rarely gets storms?
Usually yes, because lightning is only part of the job. Even in a mild climate, internal switching surges and utility transients hit daily, and a modern home is full of surge-sensitive boards in the HVAC system, appliances, and chargers. A whole-house unit plus install runs a few hundred dollars, against a single furnace board at $400–800 or a fried appliance. Low-lightning regions can simply run the device toward the longer end of the 5–10 year window rather than the short end.