photovoltaic panels installed on the roof of a house. How Much Roof Space Do You Need for Solar?

If you’re thinking about installing residential solar panels, your roof is probably the best place to put them. Most houses have enough roof space for solar panels and can easily support a large solar array. 

SouthFace Solar & Electric installs custom solar arrays based on your roof’s size and layout. Keep reading to find out how much space is needed for solar panels and the other factors we consider when deciding whether your roof is a good fit for solar power. 

Roof Size vs Solar Panel Size 

The space required for rooftop solar really depends on how much electricity you use. The more power you consume, the more solar panels you’ll need, and the more space they’ll take up. 

Solar panel sizing can vary depending on the manufacturer, but most residential solar panels are about 5.5 feet long and 3.5 feet wide, which translates to 18 square feet. That means you’ll need about 18 square feet of space for every solar panel you install.  

How Much Roof Space for 10kW of Solar?  

Ten kilowatts (kW) is a common size for residential solar panel systems, so we’ll use that as an example. You’ll likely need between 25-40 solar panels for a 10 kW system, depending on what type of solar panels you install and how much sunlight your roof gets. To keep things simple, let’s assume you need 30 panels. To fit 30 5’ by 3’ solar panels on your roof, you would need 450 square feet of usable space. 

Of course, this is just an example. You may need a smaller or larger system depending on your electricity needs. With SouthFace Solar & Electric as your solar installer, you won’t have to worry about doing the math. We’ll measure your roof and analyze your electricity usage so we can determine exactly how many solar panels your home needs and whether your roof is large enough to support them. 

Other Factors that Impact Solar Potential 

Size is an important factor to consider when installing rooftop solar panels, but you also have to think about direction, shading, and more. 

Roof Slope & Design 

Unfortunately, not every square foot of your roof is usable space for a solar installation. The slope of your roof can make it impossible to install solar panels in certain areas, as can design elements like a chimney or skylight. Ideally, you’ll want a large plane of empty roof space. 


The amount of sunlight your solar panels receive will determine how much power they can produce. Solar panel output will be reduced if they receive shade. To make up for the decreased output, you’ll need more solar panels to produce the same amount of electricity than you would in direct sunlight. 

Obstacles like trees and surrounding buildings can cast shade on your solar panels. While you can’t knock down buildings to get better sunlight access, you may be able to trim trees or branches to reduce shade. We can help you determine whether tree removal will improve your solar viability. 

Roof Direction 

The direction your roof faces also impacts its solar viability. South-facing roofs are best for solar panels, but we can get creative with your solar design to maximize production no matter what direction your roof faces. 

What If Your Roof Is Not Good for Solar? 

Most houses are suitable for solar panels, but not all of them. If your roof is not a good fit for solar panels, we will do our best to come up with an alternative option. 

Depending on where you live and how much land you have, ground-mounted solar panels could be an excellent choice. Ground-mounted solar panels are not limited by roof pitch or direction, so they can be positioned optimally for solar production. Installing solar panels on another structure, like a shed, carport, or freestanding garage, may also be an option. SouthFace has expertise in designing solar shade structures for parking lots, pool decks, and many other places where shade is invaluable.

Get a Free Solar Viability Assessment in Arizona 

SouthFace Solar & Electric is the leading solar panel installation company in Arizona. We bring more power to you with custom solar designs that are tailored to your needs and home. Our solar experts will determine how much solar power your roof can generate based on its size and sunlight access, and help you decide whether solar is worth the investment. We are a creative team and can find a solar solution that works for almost any home. 

With over 35 years of combined experience, the SouthFace Solar & Electric team has what it takes to make your solar project a success. Learn more about us and our unique process, and schedule your free solar assessment today.

Is your roof good for solar? Call 480-405-6105 or contact us to schedule a free assessment!