Electrical Load Calculations: Does Your North Idaho Home Have Enough Power?

The short answer

A load calculation adds up every electrical demand in your home, then compares that number to what your panel and service wire can safely deliver. If the math doesn't work, you have a problem. Maybe not today, but soon. Most homes built in North Idaho before the 1990s have 100-amp service. That was fine for a house with a furnace, a water heater, and a few outlets. It's often too small now.

What a load calculation actually measures

An electrician looks at square footage, heating and cooling equipment, water heater type, kitchen appliances, and any large single loads like a hot tub, well pump, or shop equipment. Each one gets assigned a demand value based on electrical code, not guesswork. The total gets compared against your panel's rated capacity, usually 100, 150, or 200 amps. If your calculated load is close to or over that number, your panel is undersized. This isn't optional or up for debate once it's calculated. It's math, and the utility and inspector will hold you to it if you add anything new.

Signs your panel might already be maxed out

You don't always need a formal calculation to suspect trouble. Some signs show up on their own:

• Breakers trip when you run the microwave and a space heater at the same time.

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

• You have a 100-amp panel and you're running central air, an electric range, and a hot tub.

• Your panel is full and there's no room for new circuits without a subpanel.

• You're planning a heat pump, EV charger, or whole-home generator and don't know if the panel can take it.

Any one of these is worth a real calculation, not a guess.

What usually triggers the need for one

In our experience, three things push people to finally get a load calculation done. First, a whole-home generator install. Utilities and code require proof the service can handle the added transfer equipment safely. Second, an EV charger. A level 2 charger alone can pull 30 to 50 amps, which is a lot to add to an already tight 100-amp panel. Third, general remodeling or additions where new appliances, a shop, or finished basement space get added to a house that was never sized for it.

What it costs to fix a shortfall

If the calculation shows you're undersized, a full panel upgrade is the usual fix. In North Idaho, that typically runs in the low thousands of dollars, depending on a few things:

• Whether you're going from 100 to 150 amp, or up to 200 amp service.

• Where the meter and panel are located, and how far the new service wire has to run.

• Whether walls are open or finished, since finished walls mean more labor to route wire.

• Utility coordination, since the power company has to disconnect and reconnect service, and sometimes upgrade their own equipment too.

• Permit and inspection fees, which are required and shouldn't be skipped. We wrote about why cutting corners on permits on a panel upgrade almost always costs more down the road.

If the panel itself is fine but you just need generator-ready circuitry, a generator inlet, interlock kit, or automatic transfer switch runs anywhere from several hundred dollars to a couple thousand, depending on distance from the panel and whether it's a manual or automatic setup. If you're planning ahead for outages, our post on getting a home generator ready for winter storms covers what that setup involves in more detail.

Cabins and second homes need this too

Cabin owners in Bonner and Kootenai counties often assume a small panel is fine because the place isn't used year-round. But if you're adding electric heat, a well pump, or planning to convert the cabin into a full-time residence, the same math applies. An undersized panel on a cabin causes the same tripped breakers and fire risk as it does in a full-time home. It just gets noticed less often, until someone's there in January running space heaters.

Getting an honest answer

The only way to know for sure if your home has enough power is to have someone run the actual numbers. Guessing based on how old the panel looks, or how many breakers are in it, isn't reliable. A proper load calculation takes into account your specific appliances, square footage, and future plans, not just a snapshot of what's installed today.

Sageland Electric has been doing this kind of work across North Idaho for over 21 years, and we're comfortable telling homeowners when an upgrade is actually needed and when it isn't. If you're wondering whether your panel can handle a generator, an EV charger, or just keeps tripping breakers for no clear reason, reach out through our contact page and we'll walk through what a proper calculation looks like for your situation.