100 Amp vs 200 Amp Panel Upgrade: Which Does Your Home Need?
A licensed Newcastle electrician breaks down the real difference and helps you choose the right service size.
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A licensed Newcastle electrician breaks down the real difference and helps you choose the right service size.
If your electrician says you need a panel upgrade, the first question that usually comes up is whether to go with a 100 amp or 200 amp service. For most Newcastle and Seattle-area homes today, the answer is almost always 200 amps — but understanding why helps you make a confident decision.
A 100 amp electrical panel was the standard in homes built before the mid-1980s. For the time, it was more than enough. Homes had fewer high-draw appliances, no EV chargers, and no heat pumps. A 100 amp service can handle roughly 10,000–12,000 watts of simultaneous load — fine for a modest household, but tight by modern standards.
In Seattle and King County, many older homes in Newcastle, Renton, and Bellevue still have original 100 amp panels. If you live in one of these homes and are not planning any major additions, a 100 amp upgrade may technically be sufficient. But given the cost difference is relatively small, most electricians — ourselves included — recommend going straight to 200 amps.
A 200 amp panel is the current standard for new residential construction in Washington State. It handles up to 20,000–24,000 watts, which comfortably supports modern homes with central HVAC, electric ranges, EV chargers, home offices, and additional living spaces. If you plan to install a Level 2 EV charger, add a heat pump, finish a basement, or add a hot tub, you will almost certainly need a 200 amp service first.
There are narrow cases where a 100 amp upgrade makes sense: a small older home with gas appliances, no plans for electrification, and a tight budget. Even then, we typically advise homeowners to look at long-term value. A 200 amp panel adds measurably more to home resale value in King County.
If your home already has electric heat, an electric range, or a dryer — or if you plan to add an EV charger or heat pump — 200 amps is not optional, it is required. You also need 200 amps if you are finishing additional living space, adding a hot tub or sauna, or if Puget Sound Energy flags your service as undersized during their interconnection review.
We had a 100 amp panel from 1979 and were planning to add a heat pump and EV charger. Clarity Electric walked us through exactly why 200 amps was the right call. The job was done in one day and PSE signed off without any issues.
- Newcastle homeowner, March 2026
A 200 amp panel upgrade in the Newcastle and greater Seattle area typically runs between $2,500 and $4,500 depending on the complexity of the existing service entrance, whether the meter base needs to be replaced, and PSE coordination. A 100 amp upgrade is slightly less — usually $1,800–$3,000 — but given the marginal difference, most homeowners upgrading today choose 200 amps.
All panel upgrades in Washington State require a permit and inspection. We handle permits and PSE coordination on every job.
Clarity Electric LLC is a licensed electrical contractor serving Newcastle, Renton, Bellevue, Issaquah, and the greater Seattle Eastside. Call us at 425-210-4791 or request a free estimate online.