Any solar installer who’s been around for a few years has inevitably faced well-meaning (and some not so well-meaning) folks asking about the cost of going solar. Some read an article somewhere and self-inform themselves with out-of-context information. Some think going solar is like getting a new furnace, and ask questions like “so what’s it cost for a single family house, two stories, 1800 square feet?” The myth we tackle in this episode: “You can estimate a solar system cost based on the size of the home it will serve.”

The solar mythbuster received this message on 8/17/2018 as a forward from a colleague:

The Myth:
“You can estimate a solar system cost based on the size of the home it will serve.”

Solar Mythbuster Investigation & Response…
Alright. I’m going to be blunt. I’m going to ask you a question. I want you to set a timer for 1 minute. Then I want you:

  1. to read the question
  2. start the timer
  3. think about how you’d answer the question
  4. continue reading this post when the timer goes off


Can you spare that WHOLE MINUTE? Yes? Great.
Are you ready? Here we go:

What are the most important factors when it comes to estimates for:

new floors (tile, wood, carpet)
new roofs
new driveways
painting a home

Start that timer!

Ok. Let me guess… it went like this:

new floors – how much floor area & what type of flooring?
new roofs – how much roof area & what grade of shingle?
new driveways – how much driveway area & what material?
painting a home – how many rooms (area) are to be painted & what grade of paint?

Its obvious, right? The main principles are:

The size of the job:
– the larger the job, the more labor, the more the job costs
– the larger the job, the more material will be needed
The grade/cost of the material:
– the better the material, the greater the cost

So, how do you think pricing for solar jobs works?

Hint: The size of a solar system is directly related to the amount of energy a site uses over 12 months.

The answer is the price depends on the the size of the system (how much energy it is expected to produce) and what grade of panels are used! Its that simple!

Lets drive this concept home with the following two scenarios:

Scenario Large Home Townhouse
Living Space 5,000 Square Feet 1,800 Square Feet
Annual Electric Usage 7,000 kWh/year 7,000 kWh/year
Array Orientation/Shade South/little shade South/little shade
Required System Size 5.8kW DC (20 290W panels) 5.8kW DC (20 290W panels)
Selected Module Grade Value Premium
Installation Price Per Watt $3.02 $3.32
System Cost 5800 * $3.02 = $17,516 5800 * $3.32 = $19,256

What is in common between the two?
The answer is obviously energy usage, array orientation, and shade conditions… which means they would require solar systems of about the SAME SIZE. System size is NOT related to the size of the home. Its related to how much capacity must be installed to cover production goals for the site (which is typically 100% of the previous 12 months of usage).

Which scenario’s system costs more?
The townhouse. Because the owner opted for premium panels, which come with a commensurate price. The cost of installation labor and inversion will be the same: each get 20 panels of roof labor, and the same electrical materials/labor. Again, the price difference is from the material cost difference of the panels.

Is the system cost directly related to the size of the home?

And… It turns out that solar pricing is even more complicated than this… why?
There are several additional parameters that must be taken into account for solar installation pricing. Here are a few of them:

  1. The location of the job. For example, jobs in Brooklyn NY are under DOB control, which have many restrictions and requirements which drive up the price. Additionally, worker’s compensation insurance in NYC is terribly expensive, so labor rates are much higher.
  2. The height of the roof. For example, its easy for installers to get panels up onto a single story cape. What about a 3 story victorian?
  3. The pitch of the roof. Time is money, and it takes more time to carefully plod along on a 40 degree roof than it will to comfortably walk on a 14 degree roof. The higher the pitch, the more expensive the labor costs.
  4. Permits. Some municipalities are easier to satisfy and deal with than others. Some make life as an installer somewhat miserable.

Solar Mythbuster Conclusion: Solar system pricing is NOT based on square footage. Its based on several parameters including: material selection, roof height, job location, roof pitch and municipality.

Solar Solutions for New Jersey, New York, and Eastern Pennsylvania