Battery Storage

Battery Sizing Calculator

Calculate battery storage needs for your home — instant results, no signup required.

Calculate Battery Size

Daily Energy Usage (kWh/day) US average is ~30 kWh/day. For essentials only, enter 10–12 kWh. Solar System Size (kW) Enter 0 if you don't have solar panels yet. Backup Duration (hours) 24 hrs covers most outages. 72+ hrs for hurricane/ice storm zones. System Type

Battery Sizing Calculator: How Much Storage Do You Need?

Use this battery sizing calculator to find the perfect battery capacity for your home. Enter your daily energy usage, solar system size (or 0 if you don't have solar yet), and desired backup duration to get an instant recommendation — including how many Tesla Powerwalls you need and the total cost after the 30% federal tax credit.

Home battery storage is one of the fastest-growing home energy investments in the US. Power outages are increasing nationwide, electricity rates are rising 3–5% per year, and the federal government is offering a 30% tax credit through 2032.

How to Use the Battery Sizing Calculator

Daily Energy Usage (kWh/day): Check your electricity bill for your average daily kWh. The US average is about 30 kWh/day. If you only want to power essential loads during an outage (refrigerator, lights, WiFi, medical devices), enter 30–40% of your total usage — typically 10–12 kWh.

Solar System Size (kW): Enter your existing or planned solar system size. If you don't have solar, enter 0. Adding solar to a battery system changes the calculation significantly — with solar, your battery recharges daily for potentially indefinite backup.

Backup Duration: Enter how many hours of backup you want. 24 hours covers most short outages. 72+ hours provides protection for multi-day outages common in hurricane or ice storm zones.

Grid-Tied vs Off-Grid: Which System Is Right for You?

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Grid-Tied Battery System

Stays connected to the utility grid. Stores solar energy and discharges at night or during peak pricing hours. During outages, automatically switches to battery power and recharges with solar. Most common and cost-effective setup for most homeowners.

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Off-Grid Battery System

Operates completely independently of the utility grid. Requires significantly more battery capacity (3+ days of autonomy) and a large enough solar array. Off-grid systems cost more but are essential for remote properties without grid access.

Battery Storage Costs in 2026

The most popular home battery is the Tesla Powerwall 3 at 13.5 kWh, costing approximately $13,500 installed. After the 30% federal ITC, your net cost is about $9,450 per unit.

Tesla Powerwall 3

Capacity13.5 kWh

Installed Cost~$13,500

After 30% ITC~$9,450

Power Output11.5 kW

Enphase IQ Battery 5P

Capacity11.5 kWh

Installed Cost~$11,500

After 30% ITC~$8,050

Power Output3.84 kW

LG RESU 16H Prime

Capacity16 kWh

Installed Cost~$14,500

After 30% ITC~$10,150

Power Output7 kW

Solar + Battery: The Best Combination

Pairing solar panels with battery storage gives you the maximum benefit: free solar energy during the day, stored power at night, and backup protection during outages. With solar, your battery recharges daily — turning a single-use backup device into a permanent energy savings system. Learn more in our Battery Basics Guide or use our Solar Savings Calculator for the complete solar + storage picture.

Quick FAQs

Can I add a battery to my existing solar system?

Yes — most modern inverters support AC-coupled battery storage. A solar + battery retrofit typically costs $10,000–$20,000 installed before incentives.

How long do home batteries last?

Most home batteries carry a 10–15 year manufacturer warranty and are rated for 4,000–6,000 charge cycles. Real-world lifespan is typically 15–20 years with proper management.