If You Want 25% of Your Home’s Power Use to be Solar: A 2025 Guide

With climate change accelerating and electricity prices rising, more homeowners are looking to solar power to meet a portion of their energy needs. If you want about 25% of your home’s electricity to come from solar, this guide will walk you through how to make it happen.

Why Go Partially Solar?

There are a few key reasons why homeowners may opt for having solar meet only 25% of their energy use rather than their full demand:

• Cost Savings Installing a full solar system to cover 100% of your home’s energy use can be expensive Going for 25% solar can help reduce the upfront investment while still lowering electric bills

• Limited Roof Space If your roof cannot accommodate enough solar panels to meet all your energy needs partial solar allows you to produce what you can.

• Future Expansion Some homeowners start with 25% solar with plans to add more panels down the road as budgets allow

• Net Metering Limits: Utilities limit the amount of excess solar energy you can sell back to the grid. Partial solar works within those constraints.

• Storm Resiliency: When grid power is down after storms, partial solar can provide backup electricity for critical loads.

No matter the reason, if your goal is for solar to meet 25% of your home’s electricity demand, the steps below will help you get there.

Calculate Your Annual Electricity Usage

The first step is figuring out how much electricity your home uses each year, measured in kilowatt-hours (kWh). Check your last 12 months of electric bills and total up your usage.

The Department of Energy says the average home uses about 10,791 kWh annually. But your actual usage could be higher or lower based on the size of your home, appliances, number of occupants, and local climate.

Once you’ve got your annual usage totaled, multiply it by 0.25 to determine how many kWh 25% of your demand would be.

For example, if your home uses 15,000 kWh per year, 25% of that is 3,750 kWh.

Choose an Appropriate System Size

Next, determine the right solar system size to produce 25% of your electricity. The size is measured in kilowatts (kW).

As a rule of thumb, you’ll need about 20-30 square feet of solar panels per kW of capacity. So for a 5 kW system, you’d need 100-150 square feet of roof space.

Work with a qualified solar installer to evaluate your specific electricity needs, roof size, and panel options to choose the ideal system size.

For the 15,000 kWh home above, a 3-4 kW system would likely cover the 3,750 kWh 25% portion.

Understand Solar Panel Options

There are a few key specs to understand when it comes to solar panels:

• Efficiency: More efficient panels convert more sunlight into energy. Look for at least 18% efficiency.

• Wattage: A solar panel’s power rating (300W, 400W etc). Higher is better.

• Type: Monocrystalline silicon panels are the most efficient and long-lasting.

• Size: Standard panels are about 65″ x 39″. Compact panels are available for small roofs.

Discuss panel options with your installer to choose products optimized for your goals and roof. Top brands include SunPower, LG, Panasonic, and REC.

Carefully Evaluate Roof Size and Orientation

To accommodate solar panels, you’ll need adequate south-facing roof space free from excessive shading. Areas that receive full sun from mid-morning to mid-afternoon are best.

Trees or other buildings that shade your roof can significantly limit solar production. Your installer will assess shading and space constraints to plan the optimal system design and panel locations.

For homes with limited suitable roof space, ground-mount systems are an option albeit at a higher cost.

Understand Local Permitting and Incentives

Most areas require permits to install solar, which your installer will take care of. But it helps to research the local permitting process and costs, which can vary significantly by municipality.

Also be sure to utilize all available federal, state, and local solar incentives and rebates to reduce costs. The federal solar tax credit is 26% for systems installed in 2025. Additional incentives can potentially cover 25-50%+ of your system cost.

Consider Battery Storage

Adding a home battery like the Tesla Powerwall allows you to store excess solar energy for use at night. This also provides backup power when the grid is down.

For 25% solar systems, a battery may be less essential. But it can optimize use of the solar power generated while also providing emergency resilience. Evaluate costs and benefits with your installer.

Focus on Energy Efficiency First

Before going solar, be sure to optimize energy efficiency. This will reduce the system size needed. Prioritize upgrades like air sealing, insulation, ENERGY STAR appliances, and LED lighting. Your utility may offer free energy audits and efficiency rebates.

The less power you use overall, the fewer solar panels you’ll require to meet 25% of your electricity needs. Energy efficiency is the perfect first step.

Final System Design and Installation

Once you’ve evaluated all the factors above, your solar installer will provide a final system recommendation tailored to your goals.

The proposal will include details on the exact number of panels, inverter specs, projected production, monitoring capabilities, and more. They’ll also pull all required permits and coordinate inspection and interconnection.

A reputable local company that has been vetted through the EnergySage Solar Marketplace is your best bet for seamless system design and installation.

Enjoy Lower Electric Bills and a Smaller Carbon Footprint

With an appropriately-sized solar array in place, you’ll quickly notice the benefits of your investment. On sunny days, your meter will spin backwards as excess energy is exported to the grid. And your utility bills will drop as solar meets about 25% of your total electricity consumption.

Going partially solar provides an ideal balance of cost savings, energy resilience, and environmental stewardship. With the right planning and preparation, 25% solar is a powerful step toward energy independence and sustainability.