Common Questions
Do I need 200-amp service?
Short answer
Not necessarily. The National Electrical Code sets 100 amps as the minimum service for a single-family home, and plenty of houses are well served at 100. Whether you need 200 depends on your actual load: a heat pump, EV charging, an induction range, a hot tub, a heated shop or a serious home office all push the calculation up. The right answer comes from a load calculation, not a rule of thumb.
What service size actually means, and how to find yours
Your service size is the amount of power the utility connection into your home is built to deliver, expressed in amps. It's set by the main breaker, the panel's rating, the meter socket, and the service entrance conductors, all of which have to match.
The fastest way to check yours: open the panel door and look at the main breaker at the top. The number on the handle, usually 100, 150, or 200, is the service rating. The panel's label inside the door confirms what the equipment itself is rated for. If the two disagree, the lower number governs.
What pushes a house past 100 amps
None of these automatically means you need 200 amps, but each one moves the load calculation, and several together usually settle the question:
Heat pump or electric heat
Electric heating is usually the single largest load in a Spokane-area home. Converting from gas to a heat pump changes the load calculation more than almost anything else.
EV charging
A Level 2 home charger is a sustained load, not a momentary one, and it runs for hours. One charger is often fine on 100 amps; two rarely are.
Induction or electric range
A full-size electric range is a significant dedicated load, and it's one of the first things a load calculation accounts for.
Hot tub or sauna
A hot tub is a dedicated high-draw circuit that runs its heater and pumps together, often in winter when the rest of the house is drawing the most.
Heated shop or outbuilding
A detached shop with heat, a compressor, and tools can rival the house itself. It frequently justifies its own sub-panel rather than a bigger service.
Serious home office
One desk with a laptop is nothing. Multiple workstations, servers, or production equipment running all day is a real, sustained load.
"My panel is full" is a different problem than "my service is undersized"
These two get conflated constantly, and the fix for each is different. A full panel means you're out of breaker spaces. An undersized service means the total power coming into the house isn't enough for what you're asking of it.
You can have a full panel on a service with plenty of capacity left. This is common in older homes where circuits were added one at a time over decades. In that case a sub-panel adds the spaces you need for a fraction of the cost and disruption of a service upgrade, and it's the right answer. A service upgrade is the right answer when the load calculation says the service itself can't carry the house. We determine which one you're dealing with before recommending either.
Plan for the loads you'll add in the next few years
The most expensive version of this job is the one you do twice. If you're replacing a panel today and you know an EV, a heat pump, or a hot tub is coming in the next few years, say so up front. Sizing the service and leaving capacity for a load you can already name costs a little more now and saves the entire second project later.
The same logic applies to remodels: the time to run the circuit for the future range or charger is while the walls are open.
What a service upgrade involves, and who's involved
A service upgrade replaces the panel, meter socket, mast, and service entrance conductors. Three parties are involved besides you:
- The electrician sizes the service with a load calculation, does the work, and coordinates the other two parties.
- Avista owns the service conductors and the meter. They require notice for a disconnect, and reconnection requires the inspection sticker on the meter socket. The homeowner owns the meter socket, mast, service entrance conductors, and panel. That is why this is your project and not theirs.
- The inspector. In the Spokane region, electrical permits and inspections come from Washington Labor & Industries everywhere except the City of Spokane, which runs its own program. In Idaho, every electrical permit starts at the state DOPL portal, which routes the job to whichever authority covers the address. The separate building permit, when one is needed, comes from the city or county.
More detail on the Avista side is in our post What Avista Does During a Panel Upgrade, and What Your Electrician Does, and the work itself is on the panel upgrade page.
Talk it through with a licensed electrician
If you'd rather have someone look at it than guess, book a time or call us. We'll tell you what we actually find.
Related questions
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- Why do my breakers keep tripping?
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- What's the difference between a panel change and a service change?
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- Common electrical questions
Frequently Asked Questions
How do I find out what size service I have?+
Look at the main breaker at the top of your panel: its rating is usually marked on the handle (100, 150, or 200). The panel's label inside the door also lists the panel's rating. The main breaker rating and the panel rating together tell you most of what you need to know.
Is 100 amps enough for a normal house?+
Often, yes. 100 amps is the NEC minimum for a single-family dwelling, and a home with gas heat, a gas range, and no EV can live comfortably at 100. The question stops being simple once you add electric heating, EV charging, or a hot tub. That's when a load calculation earns its keep.
My panel is full. Does that mean I need a bigger service?+
Not necessarily. A full panel is a space problem; an undersized service is a capacity problem. They're often confused. If your load calculation passes at your current service size, a sub-panel gives you the breaker spaces you need without touching the service, and it's frequently the cheaper right answer.
What does a service upgrade actually involve?+
The panel, meter socket, mast, and service entrance conductors are replaced and sized for the new service. A permit is pulled, Avista schedules a disconnect and reconnect (they own the service conductors and the meter) and an inspector signs off before reconnection. The power is typically off for the working day.
Should I upgrade now if I'm planning an EV or heat pump later?+
If you're already doing panel work, planning ahead is smart: sizing for a load you know is coming in the next few years avoids paying for the same job twice. If nothing else is being done, there's no urgency: get the load calculation done when the new load is real.