As every real estate person will say, its all about Location, Location, Location!
Solar is very much attuned to this.
Home builders and city design developers are only now starting to consider the average home as being a net zero structures. As a result, is likely that your home, as with most buildings in the city, is not constructed to take advantage of solar the way you might hope.
Few buildings are oriented to full south exposure let alone have the desired roof pitch for taking advantage of the perfect sun angle. This does not mean that solar is out of the question, it simply means that you have to make some choices and go with what is optimal for your situation.
It should be pointed out there are companies that you can hire who will do a full assessment of your property, take sun measurements, calculate angles, calculate solar panel layout and estimate the electrical output. For some this may be a good choice prior to making the investment in gear and going it alone.
For us, the choice was pretty simple for the base of where we needed to install, so we opted to go it alone for the most part.
A direct facing south roof is not something we had and therefore had to attempt to find the best option available.
Our house is facing South East and has (at the moment) two very large pine trees blocking and shadowing the roof making that side of the house a poor choice.
The other side of the roof, although getting a good level of sun during the later afternoon and evening, has a lot of protrusions for ventilation, sewer and furnace venting making it a poor choice for the solar panels to be installed on.
This made us look toward our garage as the next option.
The garage has one side of the roof directed North East and the other side pointed South West. We have a standard 12:3 pitch on the garage roof which is also not optimal.(It should be noted here that local legislation also restricts the distance of the solar panel mountings from the roof and the use of adjustable solar panel structures on roof tops making the likelihood of being optimal less likely for most builds.)
The side of the roof with the most available sunlight during the day is on the South West face with mid-day and afternoon sun exposure.
The North East face gets a lot of sun first thing in the morning. Although off axis for the majority of the day, still has sunlight exposure throughout the day.
Our garage roof was too small for the full 5 kW of solar we chose to install on the South West face alone, which is where we would get the majority of our sunlight, so we opted to put 3.5 kW of solar on the South West face and 1.5 kW of panels on the East face. This layout gives us a capture of the morning sun on the 1.5 kW side and then is still lit to some capacity in the afternoon and evening when we will be capturing the majority of our sunlight on the 3.5 kW west side.
We are well aware that because of this not being optimal, we will never get the full potential of the 5kW of solar that we have installed. We are ok with this because of the pre-planning we did based on our electrical usage and estimations on productivity.
All of this goes to show you do not have to be in a perfect situation for this to work or to make a difference in your power creation.