Is your building solar-ready?

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Is your building ready for a solar power system installation?

Even if your area and location have a good solar potential, your building might not be suitable for the installation of a solar electric system.

Your building is prepared for installing a solar system if:

  • You have already made it energy-efficient.
  • The roof of your building (or your yard) is unshaded, at least during the sunny hours (normally six) of the day.
  • Its roof has a Southern (or Northern, if you live in the Southern hemisphere) orientation.
  • The roof is in good condition.

How to assess your location for the solar resource?

The spot where you intend to install the solar module array should have:

a.   Clear and unobstructed access to the sun throughout the day (between 9 a.m. and 3 p.m.) and throughout the year.

This means lack of any obstacles between the sun’s rays and the solar panel array’s surface – trees, chimneys, lamp-posts, neighbour buildings, etc.

It should be noted that a spot may be unshaded during one part of the day and shaded during another part of the day. Furthermore, a site unshaded in summer might be shaded in winter, as the low position of the sun in winter casts longer shadows.

b.   Preferably a South-facing (or North-facing, if you live in the Southern hemisphere) roof.

True South (or True North, if you live in the Southern hemisphere) orientation is not mandatory.

A somehow Southeast or Southwest (for the Southern hemisphere Northeast or Northwest, respectively) facing roof is also acceptable.

It has been proven that deviation within 20-30 degrees of the True South (or True North, if you live in the Southern hemisphere) results in less than 10% degradation of solar module array’s performance, which is fairly acceptable.

Important: Pure Eastern or pure Western orientation not recommended, since as a rule, solar panel modules should be exposed to direct sunlight for at least 6 hours a day.

You should mind that installing a solar power system on a roof facing East or West might result in 20% degradation of system performance, which is a serious compromise!

The roof can be either sloped or flat. Flat roofs allow easier to implement the desired tilt angle of the solar module array, but a sloped roof will do as well.

c.   Enough space for placing solar panel modules

The area you need for your solar power system depends mainly on:

  • How much energy it is designed to produce
  • Types of solar panel modules you are going to install (monocrystalline, polycrystalline or thin-film)
  • The size of the solar panel modules (to a lesser extent since, as a rule, solar panel modules do not vary much in size).

Important: The less efficient modules you use, the greater the area you need for your solar array but also the lower the costs.

Monocrystalline modules are the most efficient solar module type while thin-film modules are the least efficient ones.

See also Solar cell types and their efficiency

Why the condition of your roof does matter

A solar power system can be installed on any roof type. There are two options for installing solar panel modules – either mounting the solar panel modules on the roof or replacing the roof tiles with solar panel modules.

As a rule, roofs with composition shingles are the easiest to work with, while those with slate are the most difficult ones.

Here are the drawbacks in case of solar panel modules mounted on the roof:

  • Modules must be removed upon performing any roof repair or replacement activity.
  • Installation of brackets and racks could cause roof leaks.
  • Roof warranty may be affected.
  • Some people might find this unattractive.

However, roof-integrated installation costs amount up to 40% more compared to roof-mounted installation.

See also Different type of Solar module mounting systems

If your roof is relatively old and is to be replaced in the near future, in order to minimize any redundant costs, a smart idea would be to replace it at the time the solar power system is being installed.

If you have a new roof, you should consult both your solar panel provider and roof repair company how the installation of a solar power system will affect your roof warranty.

Certainly, solar panel modules can be placed on the ground as well, on a fixed or tracking mount.

Anita Dhupia

Working as an electrical engineer. Writing as a student. Wanting to see someone again..

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