Your kitchen lights dim for a second when the fridge kicks on. Or the whole house flickers when a big rig rolls by outside. Maybe it’s just one lamp that’s been doing it for months and you’ve stopped noticing. I get calls about flickering lights almost every week, and about half the time it’s nothing. The other half, it’s a wiring or panel problem that needs a proper electrical repair before it becomes a bigger one. Here’s how I sort the two apart in the field.
TL;DR
- A single flickering bulb is usually a loose connection at the socket or a bad dimmer — cheap fix.
- Flickering across the whole house when large appliances start (AC, well pump, dryer) is often normal voltage sag, but worth a load check if it’s severe.
- Flickering that comes with warm outlets, a buzzing panel, or a burning smell is an emergency — shut off the circuit and call.
- Older homes in Seattle, Bellevue, and Everett with 60-100 amp panels flicker more because they’re closer to their load limit.
- NEC and Washington L&I rules require licensed electricians for panel and circuit work — this isn’t a DIY area past changing a bulb.
The One-Bulb Flicker: Usually the Easy Fix
If it’s one fixture and everything else in the house is steady, start simple. Screw the bulb in a quarter turn tighter — I’ve closed out service calls in ninety seconds because a bulb backed out from a warm-cold cycle. If that’s not it, check whether it’s on a dimmer switch. Older dimmers weren’t built for LED bulbs. LEDs draw very little current, and a legacy dimmer rated for incandescent loads can’t regulate that low a draw smoothly. NEC 404.14 doesn’t require dimmer-LED compatibility by name, but manufacturers list it, and mismatched pairs are the single most common flicker complaint I run into in newer Seattle condos with all-LED retrofits.
Fix: swap to an LED-rated dimmer, usually $15-$25 in parts plus labor if you want it done right.
“From the HVAC side, the classic call is lights dimming every time the furnace or heat pump kicks on. A brief dip on motor start can be normal; flicker that spreads across rooms or shows up with no big load running is the one we hand straight to Marcus — that’s a connection problem, and connections don’t heal.”
— Sergei Petrov, Founder & Lead HVAC Technician at SPS Pro Services
Whole-House Flicker: Voltage Sag Is Normal, To a Point
When your central AC compressor or a well pump starts up, it pulls a big surge of current for a fraction of a second — that’s called inrush current. Lights dim briefly and recover. That’s expected behavior and doesn’t violate anything in the electrical code. I see this constantly on air conditioning service calls in Bellevue and Kirkland during summer heat waves.
Where it becomes a problem is severity and duration. A quick 1-2 second dim is normal. Lights that dim for 5+ seconds, or dim dramatically enough that you notice it from another room, points to either an undersized circuit feeding that appliance or a panel that’s stretched too thin. I’ve measured voltage drops on 100-amp panels serving a house with a heat pump, an electric range, and an EV charger all fighting for the same limited capacity. That’s not a code violation on day one, but it’s a sign the panel is undersized for the home’s actual load, and NEC 220 load calculations exist for exactly this reason — sizing service equipment to what the house actually demands, not what it demanded in 1975 when the panel went in.
Aging Homes, Aging Panels
A lot of housing stock in King and Snohomish counties dates to the 1960s-1980s, when 100-amp service was standard and nobody had a heat pump, an EV charger, and a home office running three monitors at once. Add a heat pump installation or an EV charger installation to a 100-amp panel that’s already near capacity, and flickering under load becomes a regular event, not an occasional one.
This is the point where an electrical panel upgrade to 150 or 200 amps stops being a nice-to-have and starts being the actual fix. I’ve upgraded panels in older Everett homes specifically because the owner added an EV charger and started tripping breakers or watching lights sag every time the car started charging at night.
Myth-Busting: Three Things I Hear Constantly
Myth: “Flickering always means my wiring is a fire hazard.” Not usually. Most flicker is voltage sag or a loose bulb, not a fire risk. But if the flicker is paired with a warm switch plate, a burning smell, or a breaker that’s warm to the touch, that’s different — stop using that circuit and call. Warm equipment under normal load is a violation of basic safety expectations under NEC 110.3 and warrants an inspection, full stop.
Myth: “It’s an old house, flickering is just how it is.” Age isn’t an excuse to ignore it. An older home can be perfectly safe if the wiring and panel were maintained and sized correctly. Flickering is diagnostic information, not a personality trait of your house. I’d rather find a loose neutral connection now than have a customer discover it during a Seattle windstorm power event.
Myth: “LED bulbs are just bad about flickering.” Cheap LED bulbs paired with incompatible dimmers flicker. Quality LED bulbs on proper circuits and LED-rated dimmers don’t. Don’t blame the bulb technology for a mismatch problem.
When Flickering Is an Emergency
Stop and call same-day if you notice any of these:
- Flickering paired with a burning or ozone smell near an outlet or panel
- A breaker or panel box that’s warm or hot to the touch
- Flickering that gets worse when you run water heaters, the furnace, or the water heater at the same time — could mean a shared neutral or overloaded circuit
- Lights flickering only in part of the house, especially if outlets in that section also feel underpowered — this can point to a loose connection at the main panel or even the utility service point
Washington L&I requires a licensed electrical contractor for any panel, service, or branch circuit work — this isn’t legally a homeowner DIY zone past fixtures and switches you’re qualified to handle yourself under the state’s minor work exemptions. If in doubt, that’s what licensed techs are for.
Quick Diagnostic Checklist
- Is it one bulb or the whole house? One bulb: check the socket and dimmer first.
- Does it happen only when a big appliance starts? Likely normal inrush, note how long it lasts.
- Is any outlet, switch, or the panel warm to the touch? Stop using that circuit now.
- Do you smell anything burning or plasticky? Turn off the breaker and call immediately.
- Has your home added a heat pump, EV charger, or water heater upgrade recently without a panel review? Worth a load calculation.
- Is your panel original to a home built before 1990? Worth a capacity check even without symptoms.
What It Typically Costs in the Seattle Area
| Service | Typical Range |
|---|---|
| Diagnostic visit / flicker troubleshooting | $89 - $150 |
| Dimmer switch replacement (LED-rated) | $95 - $175 |
| Loose connection repair at panel or outlet | $150 - $300 |
| Whole-house surge protector install | $250 - $450 |
| Panel upgrade, 100A to 200A | $2,200 - $4,200 |
| EV charger circuit addition | $600 - $1,600 |
These are estimate ranges based on typical jobs around Seattle and the surrounding area — actual pricing depends on panel access, permit requirements, and existing wiring condition.
FAQ
Can PSE or Snohomish PUD cause flickering on their end? Yes, occasionally. Loose utility connections, transformer issues, or storm damage on the utility side can cause house-wide flicker that isn’t your wiring at all. If your neighbors report the same thing at the same time, call your utility first.
Will a whole-house surge protector stop flickering? It protects your electronics from spikes, but it won’t fix a loose connection or an undersized panel causing sag. It’s a good addition, not a flicker cure-all.
Should I be worried about flickering right after a storm? Check for loose connections before you assume it’s fine. Storm-driven wind stress can loosen service entrance connections, and that’s worth a same-week inspection even if the flicker seems minor.
If your lights have been flickering and you’re not sure whether it’s a five-minute fix or a panel issue, call SPS Pro Services at (206) 427-8907 and we’ll walk through it with you.