man and woman looking at the exterior of a house

Are you in the market for a new home? If you plan on installing solar panels, it’s wise to consider the sun exposure of a home before you decide to buy. If it isn’t well suited for a solar power system, it can be difficult to improve its solar potential. Some hurdles are relatively easy to overcome, but not all of them.

Often, you can largely determine the solar potential from the real estate listing and free satellite images. So let’s explore what you need to consider when shopping for a solar-suitable home.

Shade Reduces Solar Energy Output

Shade and solar panels are not a good combination because solar energy relies on sunshine to produce electricity. Therefore, one of the most critical factors in a well-performing solar system is little or no shading on the roof.

A little early morning or late afternoon shade won’t significantly impact your solar power production. However, if there is a lot of shade between about 10 a.m. and 2 p.m., this can hurt the return on investment of your solar panel system. Buildings, trees, and architectural features on the south side of the home can cast shade at midday, the optimal time to generate energy.

In some cases, you might be able to trim a tree branch or two to reduce shading dramatically. Sometimes, installing solar panels on an attached or detached garage might be possible instead.

Because the lifespan of a solar panel system is 25 to 30 years, it’s also essential to consider the trees you plant around your home because they can eventually cast shade on your solar system. Vegetation on the north side of the house or trees that don’t grow tall enough to shade the roof will not be problematic.

Optimal Roof Orientation

A south-facing, unshaded roof is ideal. You want your solar panels facing south to have the greatest utility bill savings and the highest return on investment. If your roof is oriented to face east or west, your system will produce about 20% less electricity than a south-oriented roof.

East-facing solar panels will generate more power in the morning while west-facing panels will have higher afternoon production. To make up for this, you could install a few extra solar panels if you have ample space, but this will increase the cost of the solar power system. If the roof faces east and is partly shaded, you may need to consider other options, like a garage roof or ground mount.

The best way to quickly determine the roof’s orientation is by using satellite imagery, such as Google Earth.

Available Roof Space for Solar Panels

The best solar-suitable home will have enough roof space to produce 100% of your household electricity. However, it can be challenging to anticipate the electricity bills when buying a new home. If the house has an electric water heater, range, and heating system, it will likely use more electricity than homes with gas appliances. If possible, obtain a year of electricity bills for the house before purchasing it to get familiar with its energy consumption.

The average home needs about 19 to 23 solar panels to produce 100% of the home’s electricity. That equates to about 335 to 405 square feet of roof space. Of course, this figure can vary a bit depending on the efficiency of the solar panels and shading.

If a home has skylights or a complicated roofline, it might be difficult to find 350 square feet of available space. Architectural features, such as dormers, can shade solar panels for part of the day, lowering your energy production.

One way to partially make up for this is to use high-efficiency solar panels, such as SunPower.

Sufficient Electrical Panel Capacity

The home electrical panel distributes electricity from the panel to the loads around the home. Typically, new homes do not need an electrical panel upgrade before going solar. However, if there is an old electrical panel or there isn’t sufficient amperage for solar electricity, you will need to upgrade the electrical panel.

Most homes need a 200-amp panel as a minimum, and upgrading the electrical panel can add $1,000 to $3,000 to the solar installation cost.

Home Energy Efficiency

Before installing solar panels, it’s crucial to examine whether there are easy ways to reduce home energy consumption. For example, installing a low-flow showerhead will save both energy and water. Check light fixtures in a new home to ensure they aren’t incandescent bulbs and upgrade to energy-efficient LED lightbulbs. Use natural ventilation when possible to decrease the use of air conditioning and wash clothes in cold water.

Assessing a Home’s Solar Potential

If having a home solar energy system is important to you, it’s a good idea to begin assessing the solar potential of a property from the real estate listing before stopping by for a showing. You’ll need to consider how much shade the roof gets, as shade will affect solar panels’ energy production. You’ll also want to make sure there is enough roof space to generate most of your electricity; skylights and other architectural features may reduce your power-generating space. And if possible, obtain at least a year’s worth of electricity bills to get a sense of how much power the home uses to help you determine if the roof is big enough to produce all your electricity.

This article was originally published on May 24, 2022, and updated in July 2023.

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By Sarah Lozanova

Sarah Lozanova is an environmental journalist and copywriter and has worked as a consultant to help large corporations become more sustainable. She is the author of Humane Home: Easy Steps for Sustainable & Green Living, and her renewable energy experience includes residential and commercial solar energy installations. She teaches green business classes to graduate students at Unity College and holds an MBA in sustainable management from the Presidio Graduate School.