What Amp Rating Does Your Home Actually Need? A Simple Explainer

Most homes built in the last 20 years need 200 amps. Older homes in Bonner and Kootenai counties often have 100 amp panels, and that's usually too small for how people live now. Here's how to figure out what your place actually needs.

The short version

60 amps: outdated, common in homes built before the 1960s. Barely enough for lights and a few outlets.

100 amps: standard for decades, still fine for a small home with gas heat and no big electric loads.

150 amps: a step up, good for mid-size homes with central air or an electric range.

200 amps: the现代 standard for most new construction and remodels. Handles a heat pump, EV charger, hot tub, and a workshop without drama.

320-400 amps: larger homes, homes with detached shops, or properties planning to add a whole-home generator plus EV charging plus other big loads at once.

Signs your panel is too small

• Breakers trip when you run the microwave and the toaster at the same time.

• Lights flicker or dim when the AC or well pump kicks on.

• You're adding an EV charger, hot tub, or shop and the panel has no room for new breakers.

• You still have a fuse box or a panel with a Federal Pacific or Zinsco brand name on it.

• Your panel is rated 100 amps and you're running central air, an electric range, and an electric water heater already.

Any one of these on its own isn't an emergency. A few of them together mean your service is maxed out.

What actually uses up your amperage

Add up the big draws in your house. Central air or a heat pump. Electric range. Electric water heater. Electric dryer. Well pump. EV charger. Hot tub. A 100 amp panel can run one or two of these without issue. Try to run four or five at once and you'll see trips or dimming, especially in winter when heat and hot water are both working hard.

This is exactly why choosing between a portable and whole-home generator often turns into a panel conversation. A whole-home generator needs an interlock or transfer switch, and if your panel is already full, something has to give.

What a panel upgrade actually costs

Upgrading from 100 amps to 200 amps typically runs in the low thousands of dollars. The exact number depends on a few things:

• Service size. Jumping to 200 amps costs more than staying at 150.

• Meter location. If the meter has to move or the mast needs replacing, that adds cost.

• Utility coordination. Avista or your local co-op has to disconnect and reconnect service, and scheduling that can affect timeline more than price.

• Permit and inspection. Bonner and Kootenai counties both require this for a service upgrade, and it's not optional.

If you're adding a generator inlet, interlock kit, or automatic transfer switch at the same time, budget several hundred to a couple thousand dollars more depending on which option you choose and how far the generator sits from the panel.

What drives the price up or down

• Distance from panel. Running new wire 10 feet costs a lot less than running it 80 feet through a crawlspace.

• Open vs finished walls. If we can run wire through an open stud bay, that's fast. If we have to open up finished drywall, that's more labor and more cleanup.

• Amp rating. A 150 amp panel costs less than a 320 amp panel, both in parts and in the wire gauge needed.

• Permit and inspection timing. This doesn't usually change the price much, but it does affect how fast the job gets done, especially in busier months.

What usually triggers the decision

Most people don't upgrade their panel just because. It's usually one of these:

• Installing a whole-home generator, which needs a properly sized transfer switch and often more amperage than an old panel can spare.

• Adding an EV charger, which alone can pull 40 to 50 amps on a dedicated circuit.

• Adding a new appliance load, like a hot tub, shop, or second heat pump, that the existing panel has no capacity for.

If any of these are on your list for this year or next, it's worth sizing the panel for all of it now rather than upgrading twice.

How to get a straight answer for your house

The only way to know for sure what your home needs is to have someone look at your existing panel, your meter, and what you're planning to add. You can see examples of past panel and service upgrades in our project gallery, or reach out through our contact page to get a straightforward quote for your property. Sageland Electric has been doing this work in Bonner and Kootenai counties for more than 21 years, and we'll tell you honestly if you need 150 amps, 200 amps, or if your current panel still has some life left in it.