Do This Before You Install Solar Panels On Your Roof

The plain truth is that your solar PV system will cost you a significant amount of cash upfront.

LISTEN, You need a proper SOLAR DESIGN before you spend anything!!
At the beginning of summer last year, a very interesting thing happened.

Tim, a very good friend of mine and a homeowner in the Colorado area was already convinced about the benefits of solar power and was looking to install solar panels on his roof.
Tim picked up the phone dialed my number and the first thing he asked me was:
What is the best solar system for my house?
Before I even responded, Tim continued…
How much savings will I achieve with Solar?

These questions puzzled me for about a minute before realizing that even with over 10 years of experience as a solar engineer, I didn’t know the answer!!!
Actually, nobody in the whole universe could possibly know the answer to these questions.
To accurately answer Tims questions, I needed to Design the entire solar PV system first.
Without a proper design, there was no way I could answer the key questions that Tim had and needed to make the final decision.

The truth of the matter is – most solar companies and information found online are absolutely misleading!!
The main interest for many solar companies is to sell and install their products to a potential customer.
The best advice I could find online about designing a solar PV system was too mediocre.

One of the highly trusted brands had an article titled – How to design a solar system. Their main steps of properly designing a solar system included:

  1. Estimate energy load by defining the total watt-hours used per month/year (The load varies greatly month – month).
  2. Calculate the size of the solar system size and work out the number of solar panels needed.
  3. Shop for all the components as per the system size.

I cringed in my seat imagining how homeowners invest over $20,000 with such minimal information.
The truth is your solar PV system will cost you a significant amount of cash upfront.
Before you buy Solar Panels it is important that you get the right system by having a professionally done Solar Design.

You see, coming up with the best solar design for a homeowner is a daunting process.

You have to take into account the technical aspects of a solar system design which include:

1. Average load profile
2. System type,
3. Solar panel connection, Size and performance
4. Solar insolation,
5. Panel orientation and tilt angle
6. Inverter type, performance and size,
7. Battery bank size and configuration,
8. Losses in cabling and connections

Additionally, when designing a solar PV project, you have to consider the environmental conditions like the

1. site location,
2. available roof area,
3. Module Weight
4. Fire codes,
5. Shading considerations.

You also have to make sure you have the right number and combination of modules and inverters to hit your energy target.

Trying to do all this for any homeowner can be a nightmare!

That’s why most solar companies and installers do not bother to explain to the customer what is expected from both a financial and energy perspective.

The Importance of A Design The Solar PV System First

A proper solar PV system design gives every homeowner an accurate representation of what they can expect after making the choice to install solar.
The solar design report clearly explains the options available, their trade-offs and costs.
Basically, the information about a homeowner’s energy demand and financial benefits become the heart of the design, quotes, and installation agreements.
A solar system design report answers the following questions:

  1. How many solar panels do I need?
  2. How many solar panels do I need?
  3. What is my energy use and how much savings will I achieve with solar?
  4. Will solar panels work on my roof?
  5. Is there enough roof area available to install the size of solar PV I need?
  6. Are there extra safety, installation or maintenance concerns?

Let’s delve into each question deeper and see how a solar system design answers each question.

1. How many solar panels do I need?

A solar design provides an accurate assessment of how many panels are needed.
The solar design also determines the sizes of the charge controller, the inverter, batteries and cabling needed before even buying and installing the system.
Before beginning and planning your PV project, you must have an understanding of how much energy you consume per day on average.
Your daily energy demands will determine how many solar panels you need. With that knowledge, calculate the number of solar panels you need using this calculator.

2. What is my energy use and how much savings will I achieve with solar?

A solar power design properly assesses a homeowner’s electrical loads and energy because any power produced by solar panels offsets an equal amount of energy which could have been sourced from the grid.
The energy offset by the Solar PV system directly signifies the projected dollar savings by the customer.
The design evaluates and discusses the homeowner’s energy demand in relation to the solar panels’ output and estimated performance.

This cannot be simply achieved by reviewing the client’s electrical bills (Although may be used in preliminary estimations).
As an engineer, I highly recommend that the actual measurements are taken (preferably over a 2 weeks period) and an actual energy profile of the building be developed.
There are several inexpensive watt-hour meters available that can be easily mounted to the main distribution board to measure specific circuits or the total electrical load.
The obtained load profile information is used to project the size of the required PV system, assess the system performance and calculate financial benefit evaluations.

3. Will solar panels work on my roof?

A proper design includes a physical or satellite site survey which gather’s information about external factors that affect the performance of solar panels on the roof.
These external factors include the local weather, roof orientation, slant etc.
The satellite site survey is properly documented and determines the best conditions and placement for the best performance of the solar panels.
Ultimately, the site survey together with your energy demand informs the solar installer whether solar panels will work on your roof.
This forms the basis and starting point for the preparation of system designs, quotations, and installation plans.

4. Is my roof area enough for the size of the solar system I need?

The roof area required for a given solar PV size will depend on many factors, including
· The solar panel dimensions,
· The spacing of solar panels on the roof, and
· The solar panel performance of the modules used.
The size and layout of the solar panels determine the roof area required for a particular the size of the solar system.
The solar design report includes an evaluation of the roof area and layout taking into account other factors such as local fire safety codes, wind, and access to the roof during fitting and maintenance.
The solar panels roof layout includes several rows with spacing between each row to prevent row to row shading.

5. Do I need to be worried about other safety, fitting or maintenance concerns?

A very important consideration you must look out for is the state and structure of your roof.
The solar design makes a determination whether the roof and its supporting structure is able to support the added load of the solar panels.
You may need a roofing professional to check the age and condition of the roof.
It is usually advisable to do the replacement of roof covering before solar panel installation if that is due in a few years time.
This will cut installation and maintenance costs because the solar panels would have to be removed before any roof works and reinstalled afterwards.
If in doubt or are concerned about any roofing issues it is sensible to involve a qualified roofing contractor in the project.

To learn more about how to Get a proper Solar PV design for your project check out this page

Kurt | Design Engineer

Kurt is a Solar engineer and consultant with experience in designing solar projects, installation, and project consultation.

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