How Many Solar Panels Do I Need for a 1,500 Square Foot Home?
One of the first questions homeowners ask solar companies is, “How many panels do I need?” There’s just something satisfying about being able to put a simple number on the project, especially if you’re still getting the hang of electrical jargon.
Nine times out of 10, the solar company’s response will be, “It depends.” And they’re not wrong. The number of panels depends on a number of factors.
But gosh darn it, you deserve a simple answer.
So, we analyzed thousands of solar systems purchased on the solar.com marketplace in 2022 to get a sense of how many solar panels a system needs based on the square footage of the home, and how much solar panels cost per square foot of living space.
Related: How Much Do Solar Panels Cost?
How Many Solar Panels Do I Need for a 1,500 Square Foot Home?
Simply put, a 1,500 square foot home typically needs around 16 solar panels with a power rating of 400W to create a system with 6.6 kW of capacity. But this number will vary from household to household based on electricity consumption, sun exposure, solar equipment, and energy goals.
The table below shows the average size of solar systems purchased on solar.com in 2022 for homes with 1,250 to 1,750 square feet of living space.
| Nationwide | California | Non-CA states | |
| Avg square footage | 1,474 | 1,503 | 1,445 |
| Avg system size | 6.61 kW | 6.39 kW | 6.85 kW |
| Number of 400W panels | 16.5 | 16 | 17 |
| Number of 300W panels | 22 | 21 | 23 |
As you can see:
- The number of panels varies by location and the power rating of the modules
- In sunny states like California, homeowners typically need fewer panels
- There’s a big difference in creating a 6.6 kW system with 300W panels and 400W panels
For the record, 400 Watts is by far the most popular power rating for solar panels and considered the industry standard.
Related reading: How Much Is a Solar System for a 2,500 Square Foot House?
How do I calculate how many solar panels I will need?
Now that we have a baseline, let’s break down 5 steps for calculating how many panels you need.
Step 1: Identify your electricity consumption
How much energy does a 1500 square foot house use?
To be honest, the square footage of your house isn’t nearly as important as your household electricity consumption, which can be found on your utility bill(s).
Let’s say it’s 10,500 kWh per year – around the national average – which boils down to 29 kWh per day.
Step 2: Set an offset based on your energy goals
Next, decide how much of that usage you want to offset with your solar system. Conventionally, solar systems are designed to offset 100% of your electricity consumption.
However, you may choose to over- or under-size your system depending on your energy and savings goals.
For now, let’s stick with 100% offset to keep things simple.
Step 3: Determine sun exposure
Sunshine plays a huge role in sizing your system. As shown in the map below, some parts of the US average nearly 6 peak sun hours per day, while others average less than 4.
Let’s say 4.5 to split the difference.
Step 4: Size your system
Now it’s time for some math. You have 4.5 hours per day to produce 29 kW (29,000 Watt-hours) of electricity consumption, so your home solar system would need to be 6.44 kW (6,444 Watts).
29,000 Watt-hours / 4.5 hours = 6,444 Watt system
Of course, this is an estimate and does not factor in factors like panel degradation and efficiency ratings. Your system will likely have to be a little larger than 6.44 kW to compensate for those factors.
Step 5: Pick a panel power rating
Solar panel power ratings range from 200W to 450W. Today, the industry standard is 400W and it would take 16 such panels to create a 6.44 kW solar system.
But watch how that number changes with the panel power rating:
| Panel power rating (W) | System size | Number of panels (rounded) |
| 250W | 6.44 kW | 26 |
| 300W | 6.44 kW | 21 |
| 350W | 6.44 kW | 18 |
| 400W | 6.44 kW | 16 |
| 450W | 6.44 kW | 14 |
So, now you know why solar companies ask for more information before estimating how many panels you’ll need. Every system is different!
How much do solar panels cost for a 1,500 square foot house?
While it’s nice to know how many panels you need, what people really want to know is the actual solar panel cost.
The cost of solar projects are typically measured in price per watt (PPW), which varies based on your:
- Location
- Incentives
- Equipment
- Add-ons (battery storage, panel box upgrade, roofing work)
The table below shows how much a 6.44 kW (6444 Watt) solar system would cost at various PPW levels.
| Price Per Watt | System Size | Project Cost |
| $3 | 6444 Watts | $19,332 |
| $3.50 | 6444 Watts | $22,554 |
| $4 | 6444 Watts | $25,776 |
| $4.50 | 6444 Watts | $28,998 |
| $5 | 6444 Watts | $32,220 |
For reference, it would cost around $50,000 to purchase the same amount of electricity from a utility provider at the national average price per kilowatt-hour increasing at 3% per year.
The bottom line
The number of solar panels you need depends more on your electricity consumption than the square footage of your house. But with some basic assumptions, you can get a rough estimate of how many panels will make up your system.
Of course, you’ll get a more precise answer by designing a custom system on solar.com and using it to generate dozens of quotes from trusted local installers.
Connect with an Energy Advisor today to see exactly how many panels you need.
