200 Amp vs 400 Amp Panel: Which Does Your Home Need?

August 17, 2026 · Family-owned electricians in North Idaho

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Most homes in Bonner and Kootenai counties do fine with a 200 amp panel. You need to step up to 400 amps when you're adding a shop, a second dwelling, an EV charger plus electric heat, or when you're building a larger new home from scratch. If you're not doing any of those things, 200 amps is probably enough, and paying for 400 is money you don't need to spend.

What decides which size you need

Panel size comes down to total electrical load, not house size in square feet, though the two are related. A 200 amp panel handles a typical home: central heat pump or furnace, electric water heater, range, dryer, well pump if you have one, and normal lighting and outlets. Most homes built in the last 30 years in this area were wired for 200 amps, and most of them never come close to maxing it out.

The math a licensed electrician runs is called a load calculation. It adds up the wattage of your major appliances and HVAC equipment, applies some standard demand factors, and lands on a number in amps. If that number sits comfortably under 200, you don't need 400. If it's pushing past 180 or so, or you know you're adding more load soon, that's when 400 starts making sense.

When 400 amp makes sense

A few situations come up again and again out here:

• A detached shop, barn, or guest cabin that needs its own subpanel fed from the main house panel.
• Electric vehicle charging added on top of electric heat, especially with a heat pump and backup electric resistance strips.
• A larger new build, roughly 3,500 square feet and up, with multiple HVAC zones, a hot tub, and a well pump.
• A small business or shop space with equipment like welders, compressors, or larger tools running on top of normal building loads.
• Homeowners who want to future-proof for solar with battery backup, since those systems often want more headroom at the main panel.

If two or more of these apply to you, 400 amps is worth serious consideration, especially if you're already opening up walls or building new. Adding capacity during construction is far cheaper than doing it later.

Other things that affect the decision

A few other factors change the answer, and they're worth checking before you commit either way.

What the utility can deliver. Your service size isn't just about the panel. It also depends on the size of the wire and transformer feeding your property. In some rural parts of Bonner and Kootenai counties, upgrading to 400 amps means coordinating with Avista or your local co-op on the service drop, not just swapping the panel. This can add cost and lead time, so it's worth a call to the utility early if you're leaning toward 400.

Cabins and seasonal properties. A lot of cabins around Priest Lake, Lake Pend Oreille, and Coeur d'Alene are on 100 or 125 amp services from decades ago. For these, the real question usually isn't 200 versus 400, it's whether the old service is even adequate anymore, especially if the owner wants to add electric heat, a heat pump water heater, or year-round living.

Sub panels versus a bigger main. Sometimes the answer isn't a 400 amp main panel at all. It's a 200 amp main panel feeding a subpanel for a shop or addition. This can be less expensive than a full 400 amp service upgrade and still gets you the capacity you need in the right place. A load calculation will show whether a subpanel is enough or whether the main service itself needs to grow.

How to decide

1. List your current major loads: heating and cooling equipment, water heater, range, dryer, well pump, any shop equipment.
2. Add anything you're planning in the next 5 to 10 years: EV charger, hot tub, shop, ADU, solar and battery.
3. Have an electrician run a load calculation with both lists. This is a fairly quick job and gives you a real number instead of a guess.
4. Check with your utility on what service size is available at your property and what an upgrade would involve on their end.
5. Compare the cost difference between staying at 200, upgrading to 400, or adding a subpanel instead. Sometimes the middle option wins.

Panel and service upgrades in this region typically run from around $2,500 on the low end for a straightforward 200 amp swap, up to $8,000 or more for a full 400 amp service with new utility coordination, trenching, or a difficult location. These are rough ranges. Site conditions, permit costs, and how much of the existing wiring can be reused all move the number.

When it's not worth upsizing

If your current 200 amp panel is in good shape, has open breaker slots, and your load calculation comes in well under capacity, there's no reason to pay for 400 amps just because it sounds like more is better. It isn't free capacity. You're paying for larger wire, a larger disconnect, and often a utility service upgrade, all for headroom you may never use.

The same logic applies in reverse. If you're already planning a shop, an EV, and electric heat, don't talk yourself into staying at 200 just to save money now. Panels and service wire are expensive to redo once walls are closed up and landscaping is in. If there's a real chance you'll need more power within the next several years, it's usually cheaper to size up once than to upgrade twice.

If you're not sure which side of that line your home falls on, a load calculation from a licensed electrician settles it with numbers instead of guesswork. Sageland Electric does these calculations for homeowners, cabin owners, and builders throughout Bonner and Kootenai counties, and can walk through the utility side of an upgrade too if that ends up being the right call.