What Size Battery Storage System Do You Need for an Eastern Washington or Idaho Home?

How to Size a Home Solar Battery Storage System

What size battery storage system do you need for an Eastern Washington or Idaho home? Proper sizing separates a smart solar battery storage investment from an undersized system that could leave you in the dark or an oversized one that unnecessarily drains your financial resources. Get the insight you need to make the best decision for your household with help from our trusted local solar company.​

 

How much solar battery storage do I need?

Solar battery storage system sizing depends on:

· How much energy your household consumes daily

· The frequency of power outages in your area

· Appliances and devices you want to power

· Peak vs. continuous electricity demands

What Size Battery Storage System Do You Need for an Eastern Washington or Idaho Home?

Integrating battery storage with solar panels in Eastern Washington and Idaho allows you to store energy for use during service disruptions and off-peak production periods. However, proper design is crucial. As with sizing your residential solar panel system, designing a solar battery backup system for your home requires a thorough analysis of key factors – not an overinflated “worst case scenario” estimation.

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Pitfalls of Sizing Your Solar Battery System According to House Size

Many online resources recommend designing your solar battery storage system based on home size:

 

· Small homes 1,500 sq. ft. or less – 5-10 kWh

· Medium homes between 1,500-3,000 sq. ft. – 10-20 kWh

· Large homes 3,000 sq. ft. or more – 20-30+ kWh

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Sadly, sizing a home energy storage system isn’t that simple. Families that want to operate electric HVAC equipment, charge EVs, wash and dry clothes and dishes, and run multiple refrigerators or other energy-intensive appliances will require additional storage. Areas that frequently experience lengthy outages will also need a larger battery bank. How can you ensure a system precisely sized to match your actual solar energy usage needs?

Consider Your Household’s Daily Energy Consumption

Many of our customers want to power their entire home as they normally would during a blackout, from lighting, internet, and personal devices to energy-intensive heating, cooling, refrigeration, cooking, and cleaning appliances. To support energy independence in lengthy outages, you’ll likely need a large, 40-80+ kWh stacked energy storage system. Our knowledgeable solar installers can determine your home’s precise requirements by using your maximum monthly energy bill to calculate daily demand, ensuring a solar panel and battery system designed to help your family achieve energy security.​

Calculate Critical Electrical Loads

If your goal is to power essential devices for 12-24 hours, such as lights, internet and phones, medical equipment, a well pump, and a refrigerator, a small 5-15 kWh solar energy storage system may meet your needs. For coverage during extended outages lasting longer than 2 days, we might recommend a larger 20-40 kWh battery backup. Our experienced team can help you precisely calculate the load for your essential appliances, so you can rest assured your family has what they need during an outage.​

Assess Grid Outage Frequency in Your Area

Recent statistics indicate power outages are increasing in duration across the U.S., from 8.1 hours in 2022 to 12.8 hours in mid-2025. Frequent, short blackouts are also becoming more common, averaging about 3.5 hours in Washington State and over 5 hours in Idaho. Homeowners in rural regions often report significant delays in service restoration, making it essential to evaluate your preferred coverage window when determining the ideal solar battery storage system size for your home.

 

Our experienced solar installers recommend:

 

· 1 day backup power storage for outage emergencies in areas with grid stability

· 2 days backup energy storage in areas that experience moderate outages

· 3-5 days backup solar energy storage for homeowners in rural areas​

 

Are you worried you’ll fall short on stored solar power? Our modular battery systems allow you to easily boost your storage capacity as your needs – or budget – change.

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Inverters and Peak Vs. Continuous Power Demands

Solar battery inverters convert direct current (DC) electricity produced by your panels into alternating current (AC) electricity to use in your home and charge your solar energy storage system. Inverters are rated for surge/peak power (the higher wattage burst required to start energy-intensive appliances like heat and air) and continuous power (the maximum wattage an inverter can sustain for an extended period without overheating). Our residential solar design experts provide precise load calculations, ensuring the right size inverter for reliable performance when you need it most.

Ensure Your Solar Energy Storage System Meets Your Needs

Find out what size battery storage system you need for an Eastern Washington or Idaho home with service from the solar power system design experts at PacWest Solar. Contact us at 509-929-2728 to schedule a solar energy assessment in Kootenai County (Athol, Coeur d’Alene, Dalton Gardens, Fernan Lake Village, Harrison, Hayden Lake, Huetter, and Post Falls), Spokane County (Airway Heights, Cheney, Deer Park, Liberty Lake, Medical Lake, Millwood, Spangle, and Spokane), or Pullman today.